H') SUGGESTED ECOLOGICAL RESEARCH

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Copies of this document are available
      to the public through the
National Technical  Information Service
      Springfield,  Virginia 22161

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     A STATEMENT OF CONCERNS AND
     SUGGESTED ECOLOGICAL RESEARCH

             REPORT NO.  1

                 OF THE

LAKE MICHIGAN COOLING WATER STUDIES PANEL
       THE PANEL IS SUPPORTED BY THE

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
          REGION V, CHICAGO, AND THE
         POLLUTION CONTROL AGENCIES OF
ILLINOIS, INDIANA, MICHIGAN, AND WISCONSIN
              EDITED BY
          CALDWELL D.  MEYERS
                 AND
           KARL  E.  BREMER

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                 QUALIFYING STATEMENT


     The Panel  does not unanimously recognize nor endorse
all concepts and recommendations in each section of this
report.
     This report is the result of many months of thought,
discussion and  work by the Section authors.   Their objec-
tive has been to produce a statement of concerns which
would assist in development of investigations of the effects
of cooling water use on Lake Michigan.  The  priority lists
are an attempt  to focus further on key gaps  in understanding.
It is hoped that this report will  spark research, help
realize goals,  and provoke discussion leading to continuing
modification of its content.  Such modification is anticipated
and is a desirable result of its production.   It is a working
document.
     The Panel  fully recognizes the many implications this
report carries  to cooling water users and to  those responsible
for regulation.  However, this report is not  intended to be
a regulatory document.

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                        SECTION  AUTHORS



Section I    Introductory Considerations  of Lake Michigan

                       Caldwell  D.  Meyers


Section II   Data Requirements  Related to Lake Michigan Studies

                       Caldwell  D.  Meyers
                         Jerrold H.  Zar
                       Andrew J.  McErlean
Section III   Measurement of the  Effects  of Cooling Water Use
             on  Physical  Parameters

                       John Z.  Reynolds
                       Wesley  0.  Pipes
                          Howard  Zar
                     Clifford  H.  Mortimer
                       Barton  M.  Hoglund
Section IV
Measurement of the Effects of Cooling Water Use
on Chemical Parameters

          Wesley 0.  Pipes
          Carl T.  Blomgren
          John L.  Winters
Section V    Measurement  of  the  Effects  of  Cooling  Water Use
             on  Primary Producer and  Consumer  Communities

                      Eugene  F.  Stoermer
                          John  Neess
Section VI
Measurement of the Effects of Cooling Water Use
on Macrozoobenthos

       Carlos M.  Fetterolf, Jr.
            Merle H.  Maass
          Andrew  J.  McErlean
           Alfred M.  Beeton
           Wesley 0.  Pipes

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                        SECTION AUTHORS
                          (continued)
Section VII  Measurement of the Effects of Cooling Water Use
             on the Fishery

                        Thomas A.  Edsall
                        Thomas G.  Yocom
Section VIII Measurement of the Effects of Cooling Water Use
             on Entrapped and Entrained Organisms


                        Arthur S.  Brooks
                        James G.  Truchan
                        John Z. Reynolds
                        James R.  Gammon
                        Thomas A.  Edsall
Section IX   Radioecological  Considerations  Related to Cooling
             Water Use
                      Phillip F.  Gustafson
                                VI 1

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                       ACKNOWLEDGEMENTS
This report would not have been possible without the strength
and combined effort of the members  and participants of the
Lake Michigan Cooling Water Studies Panel.

It is appropriate to recognize the  wise counsel  and thoughtful
help afforded the editors by Wes Pipes, Carlos Fetterolf,
Dick Herbst, Jerry Zar and Bob Otto toward  this  ultimate version
of Report No. 1.   The Panel extends special  appreciation to
Delores C. Sieja  for secretarial assistance  in final preparation
of the Report.
                          i x

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                    GENERAL  TABLE  OF CONTENTS
Qualifying Statement 	
Section Authors .     	
Acknowledgements.     	
List of Figures .     ,
List of Tables  .     	
General Introduction 	
Proposed Definitions with Application to
Lake Michigan        	
Section I
Section II
Section III
Section IV
Section V

Section VI
Section VII
Introductory Considerations of Lake Michigan
Data Requirements Related to Lake Michigan
Studies    	
Measurement of the Effects of Cooling
Water Use on Physical  Parameters
Measurement of the Effects of Cooling
Water Use on Chemical  Parameters
Measurement of the Effects of Cooling
Water Use on Primary Producer and Consumer
Communities	
Measurement of the Effects of Cooling Water
Use on Macrozoobenthos 	
Measurement of the Effects of Cooling Water
Use on the Fishery     	
Section VIII  Measurement of the Effects of Cooling Water
              Use on Entrapped and Entrained Organisms
Section IX
Appendix
Radioecological  Considerations Related to
Cooling Water Use      	
Comments of Members and Participants
of the Panel related to Report Number 1
.  111
    v
   ix
. xiii
   xv
    1

.   12
.   13

.   47

.   77

.  101

.  121

.  167

.  235

.  307

.  343
.  349
                                  xi

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                    LIST OF  FIGURES
Figure VII  -  1.   Principle problem areas associated with
     power  plant intakes	   .    .  248

Figure VII  -  2.   Principle problem areas associated with
     power  plant discharges  	  249

Figure VII  -  3.   Suggested sampling stations for fisheries.
     investigations  of Lake Michigan 	   259
                            xiii

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                   LIST OF TABLES
Table I - 1.   Dimensions of the Great Lakes   ...     17

Table IV - 1.   Water quality parameters to be considered
     in site  selection studies  and monitoring studies.    105

Table IV - 2.   Chemicals used in plant operation .    .    106

Table IV - 3.   Some atmospheric contaminants which
     may appear in cooling tower recirculating water .    108

Table VI - 1.   Estimates of abundance (number/m2),  by
     depth, of two benthic taxa from the central
     and southern regions of Lake Michigan
     1964 - 67	174

Table VII - 1.  Fish fauna previously or currently
     common to Lake Michigan	239

Table VII - 2.  Gil 1 net specifications for various
     mesh sizes	267

TableVIII - 1.  Sample manipulation and comparison
     to assess the effects of the power plant on
     rate  of primary  production through the use of
     14C uptake	322
                          xv

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                    GENERAL INTRODUCTION

                    Purpose of the Report

     This report outlines scientific questions and some methods
that might be used to obtain answers regarding the ecological
effects of the intake and entrainment of water, the introduction
of waste heat, the introduction of specific chemicals, and the
release of radionuclides associated with condenser cooling.  It
is anticipated that the report will produce improvements in re-
search design and a trend toward standardization of results.  It
may also provide the  basis for the selection of appropriate loca-
tions for more intensive research and for the possible generaliza-
tion of the results at those locations to wider areas of the Lake.
The Panel recommends  priority research studies leading toward an
understanding of the  whole Lake and designates specific studies
and their appropriate priorities.
           Description and Objectives of the Panel^

     The Lake Michigan Cooling Water Studies Panel is a technically
oriented group formed at the suggestion  of representatives to
the joint public sessions of the Lake Michigan States and the U.S.
Environmental Protection Agency.  In a message to the joint Federal-
State Conference of November 1972, the Regional Administrator of
EPA, Mr. Francis; T. Mayo, cited the need for development of  1)
monitoring programs to assess possible "damage to the aquatic en-
vironment of Lake Michigan attributable to existing and planned

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cooling water use,  2) criteria to trigger employment of appro-
priate corrective measures should damage become evident, and 3)
mechanisms with which to make an overall assessment of the damage
that may occur to the Lake's ecosystem from waste discharges
scattered at various points around the Lake.  He then suggested
formation of a group to review these propositions and charged
them to:
     -- review background information dealing with past, present
     and future studies relating to thermal discharges to Lake
     Mi chigan;
     -- make assessments as to whether the individual studies
     concerning thermal discharges will  adequately assess damages
     attributable to that cooling water use;
     -- assess the pertinence of individual localized studies to
     monitor changes in the overall  lake ecosystem;
     -- recommend, as necessary, additional efforts that should
     be expended to assess environmental effects of the use of
     Lake Michigan water for cooling.

     This enjoinder and these charges have been accepted by the
Panel as objectives for its deliberations beyond production of
this report.
     Actual formation of the Panel was put in motion by Mr. Mayo
in December 1972.  The Panel consists of the following members,
alternates and contributors:

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                       Members and Alternates
   State

ILLINOIS
Members:
          Name
Mr. David D. Comey
             Dr. Wesley 0. Pipes
             (Until January 17,1975)

             Mr. William V. Pye
             (Until May 9,1974)
             Mr.  Thomas McSwIggin
             Dr. Jacob Verduln
     Affi liation
Businessmen for the
Public Interest,
Chicago, Illinois

Northwestern University,
Evanston, Illinois

Illinois Environmental
Protection Agency,
Springfield, Illinois

Illinois Environmental
Protection Agency,
Springfield, Illinois

Southern Illinois University
Carbondale, Illinois
Alternates:  Mr.  Carl T.  Blomgren
             Dr.  John Neess
                             Illinois Environmental
                             Protection Agency,
                             Chicago, Illinois

                             University of Wisconsin,
                             Madison, Wisconsin
INDIANA

Members:
Mr.  Gary Doxtater
             Dr.  James R.  Gammon
             Mr.  John L.  Winters
Aquatic Controls Inc.,
Seymour, Indiana

DePauw University,
Greencastle, Indiana

Indiana Stream Pollution
Control Board,
Indianapolis, Indiana
Alternate:    Mr.  Harold L.  BonHomme
                             Indiana Stream Pollution
                             Control Board,
                             Indianapolis, Indiana

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State
          Name
     Af f i 1 iation
 MICHIGAN

 Members :
Mr. Carlos M. Fetterol f ,Jr.
              Dr. John Z. Reynolds
              Dr. E. F. Stoermer
Michigan Department of
Natural Resources,
Lansing, Michigan

Consumers Power Company,
Jackson, Michigan

University of Michigan,
Ann Arbor, Michigan
 Alternates
 WISCONSIN
Dr. Claire L. Schelske
              Dr. James G. Truchan
University of Michigan,
Ann Arbor, Michigan

Michigan Department of
Natural Resources ,
Lansing, Michigan
 Members:      Dr. Alfred M. Beeton
              Mr. Nicholas A. Ricci
              (Until January 8, 1974)

              Dr. Frank Boucher
              Dr. Clifford H. Mortimer
                             University of Wisconsin,
                             Milwaukee, Wisconsin

                             Wisconsin Electric Power Co.,
                             Milwaukee, Wisconsin

                             Wisconsin Electric Power Co.,
                             Milwaukee, Wisconsin

                             University of Wisconsin,
                             Milwaukee, Wisconsin
Alternates
Dr.  Arthur S.  Brooks
              Mr. Kenneth Lehner
              (Until September 1,  1974)

              Mr.Merle H. Maass
              Dr.  John Ney
University of Wisconsin,
Milwaukee, Wisconsin

Wisconsin Electric Power Co.,
Milwaukee, Wisconsin

Li nineties Inc . ,
Milwaukee, Wisconsin

Wisconsin Electric Power Co.,
Milwaukee, Wisconsin
FEDERAL"

Members:
Mr. Yates  M.  Barber
(Until August 30, 1973)
NOAA, National Marine
Fisheries Service,
Washington, D. C.

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   State                Name

FEDERAL(continued)

Members:     Dr. Thomas A. Edsall



             Dr. Philip F. Gustafson


             Dr. Andrew J. McErlean
                                  Affiliation
                             U. S. Bureau Sports
                             Fisheries and Wildlife,
                             Ann Arbor, Michigan

                             Argonne National Laboratory
                             Argonne, Illinois

                             U. S. Environmental
                             Protection Agency,
                             Washington, D. C.
Alternates:  Dr. Donald L. McGregor
             Mr. Barton M. Hoglund
             (Until January 1, 1975)
Chai rman:
Techni cal
Secretary
Recording
Secretary
Mr. Karl E. Bremer
             Mr. Caldwell D.  Meyers
             (Until October 1,1974)
Howard Zar
(Until June 1,  1974)
Ms.  Marion Young
Argonne National Laboratory
Argonne, Illinois

Environmental Technology
Assessment,
Oak Brook, Illinois

U.  S.  Environmental
Protection Agency
Chicago, Illinois

U.  S.  Environmental
Protection Agency
Chicago, 111inois

U.  S.  Environmental
Protection Agency
Chicago, Illinois

U.  S.  Environmental
Protection Agency
Chicago, Illinois
                          Contributors
Dr. Wayne P.  Alley
Mr.  Jar! Hiltunen
Mr.  Peter Howe
Mr.  John H.  Hughes
Mr.  Gary MiIburn
                             California State University
                             Los Angeles, California

                             U.  S.  Fish and Wildlife
                             Service, Ann Arbor,Michigan

                             Commonwealth Edison Co.,
                             Chicago, Illinois

                             Commonwealth Edison Co.,
                             Chicago, Illinois

                             U.  S.  Environmental
                             Protection Agency
                             Chicago, 111inois

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                          Contributors
                          (continued)
Dr. Samuel C. Mozley                University of Michigan,
                                    Ann Arbor, Michigan
Dr. Robert G. Otto                  Industrial Bio-Test
                                    Laboratories, Inc.
                                    Northbrook, Illinois
Mr. Pete Redmon                     U. S. Environmental
                                    Protection Agency,
                                    Chicago, Illinois
Dr. James J. Reisa                  Council for Environmental
                                    Quality, Washington, D. C.
Dr. Steven Spigarelli               Argonne National Laboratory
                                    Argonne, Illinois
Mr. Thomas Yocom                    U. S. Fish and Wildlife Service
                                    Ann Arbor, Michigan
Dr. Jerrold H. Zar                  Northern Illinois University
                                    DeKalb, Illinois
      The Chairman, Technical Secretary, staff support, and fi-
nancial support for the Committee are contributed by Region V, EPA.
      At the date of this writing, the Panel has had twenty-five
monthly meetings.
      At the second Panel meeting on January 30,1973, the follow-
ing standing subcommittees were formed from the appointed Panel
members and alternates; Fisheries, Microbiology, Chemistry, Physical,
                                               ">*,
Benthos, Data Handling and Evaluation, Radioecology, and Entrainment
and Entrapment.   Each of these Panel subcommittees consist of one to
six members permitting full  use of the expertise of the individual
members to consider subdisciplinary problems, and for preparation of
this report.   Alternates, observers, professional  colleagues and
others interested in the future of the Lake also made substantial
contributions to the subcommittees, to the Report, and by extension,
to the effectiveness of the Panel.

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                      Priority  Research
     Most issues of water pollution resolve into conflict between
competing demands for use of a particular water resource.  The issue
of thermal discharges to Lake Michigan reduces to an attempt to as-
certain the extent to which use of the Lake for cooling large stream
electric generating stations is compatible with the protection and
propagation of a desirable community of aquatic organisms and with
recreational  use of the Lake.  There is no doubt that Lake Michigan
will  continue to be used for cooling, for aquatic life, and for
recreation; there is doubt that these uses are compatible at various
levels.

     The Lake Michigan Cooling Water Studies Panel  was formed as a
technical  and scientific group to examine evidence  relating to the
effects of cooling water use.  As such, the Panel  is not attempting
to determine  the relative values  of cooling use, aquatic life use,
and recreational use.   These value judgments must perforce be made
by the citizens  of the several states and their elected and appointed
representatives.  The  task of the Panel is to make  recommendations as
to the types  and value of scientific information available as an
input to the  political, decision-making process.

     Studies  of  the effects of cooling water use on Lake Michigan
have  been  in  progress  for over seven years. With few exceptions these

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studies have been  oriented  toward  the  local effects of individual
power plants.   Studies  commissioned  and supported by individual
utility companies  will,  no  doubt,  continue to focus on local
effects.  The needs  recognized by  the  Panel provide a mechanism
for coordinating individual studies  to develop information on
lakewide effects and to  eliminate  from individual studies those
elements either adequately  explored  or obviously unfruitful.

     Since its  inception, it was the intention of this Panel to
identify areas  of  ignorance which  seem to be the most formidable
barriers  to an adequate  understanding of the effects of cooling
water use on the biota  of Lake Michigan.  Stated conversely, the
Panel focused on additional steps  or research which, when accomplished,
would most rapidly increase our understanding of the effects of cool-
ing water use.  Since it was difficult to isolate these areas of
research, the Panel used the following methodical approach:

       1.  Recognition of primary  areas of ecological  con-
           cern by division of the Panel, and of its delibera-
           tiWis,  into eight subcommittees; e.g., Fisheries,
           Physical, Chemical, etc.
       2.  Development of a research program to elucidate the
           effects of cooling water use within those sub-
           committees by discussion and deliberation based on

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          knowledge, experience, published literature, and con-
          sultation.

       3. Development of priority lists, with appropriate
          numerical values based on the availability of
          relevant data, for those areas of knowledge which
          are barriers to an adequate understanding of the
          effects of cooling water use.  (These lists have
          been placed at the end of the appropriate sections)


     The next step was to examine the priorities to which the Panel
has ascribed the highest degree of urgency and to attempt to select
several key issues.  The criteria for selection of key issues were
that they be recognized (1)   as steps facilitating the orderly use
of data for well documented  answers to the remaining questions
about cooling water use or (2)  as statements  embodying the ultimate
goals of the  Panel.   The key issues  identified are important to
all studies of cooling water use on Lake Michigan as a group but
all issues are not pertinent to any individual study.   For instance,
the subcommittees on  macrozoobenthos, plankton, and fisheries ob-
serve that although methods  of  identification of species  and their
distribution in a local  study area  may be  well-known,  the absence
of such basic data for the Lake as  a  whole is recognized  as a
very real barrier to  the understanding of  possible lakewide effects.

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     The ultimate step was to obtain concurrence of the Panel in
selection of issues of highest priority and this has resulted in
the following, not necessarily in order of importance:

     1.  To determine the periods of time, and extremes and
         average temperatures to which aquatic organisms are
         exposed when they meet elevated temperatures in dis-
         charge plumes and to evaluate available data to de-
         termine the feasibility of detecting ecological
         effects attributable to cooling water use.

     2.  To  standardize units of measurement for each para-
         meter for which environmental data are collected,
         by agreement between Lake Michigan investigators
         and institutions, so that information from the
         large number of local studies can be expeditiously
         integrated for consideration of lakewide effects.

     3.  To develop a taxonomic and zoogeographic characteriza-
         tion of the Lake Michigan biota.
     4.  To facilitate organization of Lake Michigan data to
         determine location and design of discharge and intake
         structures to minimize important biological effects.


     These are clearly issues which must be resolved before
questions of lakewide effects can be answered.  This does not imply
that each utility company and governmental agency provide answers
                                10

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for each of these questions, for that would be redundant and
wasteful.   Just as individual  sections of this Report describe
studies for local and lakewide effects, these priorities refer to
broadly applicable studies useful   to all interested parties.  An
organizational  effort is clearly needed to focus resources toward
cooperative efforts which will advance the overall  understanding
of the effects  of cooling water use.
                                11

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                     PROPOSED DEFINITIONS
               WITH APPLICATION TO LAKE MICHIGAN

     In an attempt to provide a common terminology from which to
address Lake problems, the Panel stipulates the following defini-
tions of the water zones:
Profundal Area
     (Approximately 45 meters and deeper) - that area of the lake
in which the lake bed is in the hypolimnion in the summer and in
which the temperature of the whole water column does not generally
fall below 2C in the winter and over which a continuous ice sheet
forms only for brief intervals in exceptional  years.
Sublittoral Area
     (Approximately 10 to 45 meters deep) - that area of the lake
in which the lake bed in the summer is sometimes in the hypolimnion
and sometimes in the epilimnion depending upon the occurrence of
internal waves and upwellings.
Littoral Area
     (Less than approximately 10 meters depth) - that area in which
(1) most of the surface wave energy is dissipated, in which sedi-
ments (if present) are frequently resuspended  by wave action and
where the physical conditions are often suitable for growth of
attached algae and sometimes macrophytes, (2)  where epilimnetic
water is the dominant medium, but, where hypolimnetic water may
occasionally intrude via upwellings or internal waves, (3) con-
taining the beach zone.  The outer limits of the beach zone may be
defined as the outer limits of breaking waves  in severe storms.
This limit is determined by water depth, wind  fetch and exposure.
Only in the beach zone, so defined, are wave-induced, longshore
and rip currents found.
                             12

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                  SECTION I
INTRODUCTORY  CONSIDERATIONS  OF  LAKE  MICHIGAN

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Section I. INTRODUCTORY CONSIDERATIONS OF LAKE MICHIGAN
                        TABLE OF CONTENTS

Characteristics of Lake Michigan   	   16
     Location and Dimensions   	   16
     Geologic Description	   .    .    .18
     Physiographic Description 	   19
     Physical and Chemical Description .    .    .   .    .    .19
         General Physical   	   19
             Thermal Characteristics   .    .    .   .    .    .20
             Temperature    .   .   .	20
             Transparency   	   23
         General Chemical	    .24
             Natural Contributions 	   24
             Cultural Contributions	24
             Dissolved Solids  ........   24
             Chlorides      	25
             Carbonates	25
             Oxygen and Redox Potential	26
             Phosphorous	26
             Nitrogen	26
             Organic Compounds 	   27
             Calcium and Magnesium 	   28
             Sulfur	28
             Silicon	29
             Iron and Manganese	^9
             Trace Elements	^9
             Radionuclides  	   31
                                 14

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        Biological  Characteristics 	 31
                Bacteria and Fungi	31
                Invertebrates	33
                Algae	34
                Fish.    .    .    ..    .    .    .    .    .    .36
        Summary of  Outstanding Features	38
        Use of the  Resource	.39
        Basin Growth	40
        Correlation of Basin Growth  to Basin  Uses  .    .    .41
Problems Resulting  from  Increased Use	42
        Conflicts of Multi-Use Concept .    .        .    .    .42
        Eutrophication.    .	    .43

Literature Cited	45
                                15

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    Section I.  INTRODUCTORY CONSIDERATIONS OF LAKE MICHIGAN
                CHARACTERISTICS OF LAKE MICHIGAN

     The material in this section of the Report is drawn largely
from data presented in the Great Lakes Basin Framework Study, 1972.

                      Location and Dimensions
     Lake Michigan is the third largest of the Laurentian Great Lakes
(Table 1-1) and the sixth largest freshwater lake in the world.  It
is bordered by the states of Wisconsin, Illinois, Indiana, and
Michigan and is the only lake in the group entirely within the borders
of the United States.
     The maximum length of the Lake is 307 (494 km) miles.  The
maximum width of the northern basin (from Little Traverse Bay to
Little Bay de Noc) is 118 miles (190 km); the southern basin (from
Grand Haven to Milwaukee) is 75 miles (121 km) wide.
     Lake Michigan is a relatively deep lake with a maximum depth of
923 feet (281 m) and a mean depth of 276 feet (84 m).   The volume is
estimated to be 173 trillion cubic feet or 1,181  cubic miles
(4,919 km ) at average lake level, with an areal  surface of 22,400
                       P
square miles (57,991 km ), and a land drainage basin in excess of
45,400 square miles (117,535 km2).
     The shoreline of the Lake is regular in the southern two-thirds
of the basin but less so in the northern one-third.  The total shore-
line extends 1,660 miles (2,671 km).   Shoreline and shallow areas of
Lake Michigan are important to the effectiveness of the Lake as a
productive unit since a large portion of the biota depends upon
shallows for reproduction, feeding, and as nursery grounds for
immature organisms.
                              16

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                  Table 1-1.   Dimensions  of the Great  Lakes.
Lake1
Superior
Michigan
Huron
St. Clair
Erie
Ontario
Length
(mi)
.350
307
206
26
241
193
Breadth
(mi)
160
118
183
24
57
53
Water
surface
(mi)
31.820
22,400
23,010
490
9,930
7,520
Drainage Avg. surf. Elev. Mean
Basin above mean sea discharge
level since 1860
(mi) (ft) (cfs)
80,000
67,860
72,620
7,430
32,490
34,800
602.20
580.54
580.54
574.88
572.34
246.03
73,300
55,000
177,900
178,000
195,800
233,900
Max.
depth
(ft)
1,333
923
750
21
210
802
Mean
depth
(ft).
487
276
195
10
58
283
from Beeton, A.M.  and D.C.  Chandler (1966).

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                      GEOLOGIC DESCRIPTION

     The stratigraphy of the Great Lakes basin has determined both
land form development and the mineralogical composition of ground
and surface waters.  Lithologic units range from Precambrian to
Recent and can be grouped into three time-strati graphic divisions
with unique origins and impacts:   Precambrian, Paleozoic, and
Cenozoic.
     Precambrian units consist of complex folded and faulted
igneous, metamorphic and sedimentary aspects; Paleozoic are largely
of marine or strand-line origin;  and Cenozic are largely consolidated
sediment deposited from Precambrian and Paleozic strata from within,
and north of, the basin.  Paleozoic and Cenozoic depositions, as
well as major erosional  and depositional land forms, were a result
of Pleistocene glaciation during  the four glacial  periods (Nebraskan,
Kansan, Illinoisian, and Wisconsin).  These sedimentary strata were
also subjected to regional  folding resulting in outcrops such as
the Wisconsin Dome and the  Findlay - Algonquin Arch, which effectively
determine the size and direction  of the drainage of Lake Michigan.
The Michigan Basin has a-saucer-shaped cross-section with Precambrian
strata sloping to their  greatest  depth under the approximate center
of the lower Michigan peninsula.   Due to this alone, and to tectonic
outcrops previously mentioned,  the strata of the Eastern shore are
Mississippian-Pennsylvanian with  the center of the Lake underlain
largely by a Silurian-Devonian  series.  Lake Huron has  a similar
stratigraphic profile on the eastern side of this  depositional  saucer.
                              18

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                  Physiographic  Description

    Lake Michigan is located in the Interior Lowlands Province
which is characterized by better drainage than areas to the North,
by glacial moraines, and by outcrops of resistant, dipping, Pre-
Pleistocene strata.   An example of the latter is the Niagara Es-
carpment to the north and the west of Lake Michigan.  Glacial
sediments are either morainal or non-morainal debris with the
latter glacio-1acustrine, glacio-f1uvial  and eolian sediment.
Due to glaciation, the drainage basin of  Lake Michigan (along with
Superior and Huron)  is poorly developed and  the residence time of
water in the basin is extended.
              Physical  and Chemical Description
    The  physical  and chemical properties  of  the Lake are of great
significance to its  possible use as a resource, but, in light of
the number of documents on the  subject, and  since the purpose of
this  section is introductory, the  treatment  here will not be ex-
haustive.
General  Physical
    Important properties of the  waters of Lake Michigan such as
circulations, viscosity, ice formation, sedimentation, distribution
of suspended and  dissolved solids,  chemical  reaction and interaction,
biological  productivity, waste  assimilative  capacity, rate of eutro-
phication and many others, depend  in a large part on the temperature,
pressure and density of the water.   The most significant thermal
properties  are: latent heats of fusion and vaporization, specific
heat,  coefficient of thermal conductivity and coefficient of eddy
conductivity.   Density is itself dependent on composition of the water
and varies  with temperatures as  affected  by  solar radiation and  to
                                   19

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a much smaller extent on man-influenced introductions.  Composition
of the water, and especially dissolved and suspended solids, affect
transparency which in turn affects incoming radiation, temperature,
heat storage, loss of heat, photosynthetic rate, chemical  reaction,
evaporation, modification of the water and, ultimately, lake circu-
lation.  The dependence and interdependence of these factors on the
lake waters can easily be recognized.
         Thermal  Characteristics
    Since temperature and the heat balance of the Lake are primary
subjects of this Report, these characteristics will  be most thoroughly
covered.  The specific heat of water is very high; water stores large
quantities of heat, does not give it up readily, and acts  as a thermal
mediator in the atmospheric and terrestrial environments.   In general,
the thermal conductivity of water is low, but since  water  is rarely
motionless, heat transfer is effected through turbulence and is
dependent upon mixing, circulation, stratification and climate.  It
should be observed that viscosity, which  is temperature dependent as
a non-linear function, also affects transport, stratification and
other aspects of circulation.
    Interfacial  reactions are  affected largely by the latent heats of
fusion and vaporization which  for water are among, the highest of all
substances.
         Temperature
    Lake temperatures vary with latitude  and depth.   Depths  controls
heat storage, absorption, and  transfer, but the distribution is also
strongly affected by wind driven mixing.   Since winds in Lake Michi-
gan are predominately westerlies, warmer  waters generally  appear on
                                   20

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the eastern shore and cold water up-wellings occur in the west.
Highest variation in mean water temperatures on the Great Lakes
occurs during mid-summer, while the range of variation is reduced
sharply in the fall  during which hypolimnetic cooling is signifi-
cant; lowest variation occurs in late winter.
     Vertical variation is also affected by many of the mentioned
parameters but winds are the basic mechanism of mixing.  During the
spring warming phase following ice break-up, deeper waters are
colder than 4C and less than maximum density.
     The following is a description of the development of the thermal
bar by Dr. C.H. Mortimer of the Center for Great Lakes Studies,
Milwaukee, Wisconsin:
     "The spring warming phase first affects shallow nearshore waters,
in which stratification develops,  while the offshore water mass re-
mains in its homo-thermal mixed winter condition, typically at temper-
atures well below 4C.  Between the offshore water mass and the near-
shore stratified water a very narrow transition zone forms, often
marked by a nearly vertical  4C isotherm.  This  zone, known as the
thermal bar, is interpreted as a convergence brought about by the
mixing of the warm inshore and cold offshore masses at the conver-
gence to produce a mixture which,  being close to 4C, is denser than
the parent water masses, and therefore sinks.
     As the spring heat influx continues and strengthens, the volume
of nearshore stratified water increases and the "bar" (4C isotherm)
moves offshore.  There are usually striking chemical and optical  con-
trasts at this time, between inshore and offshore water, because  in-
flows from rivers and municipal and industrial  sources remain tempo-
rarily trapped inshore of the bar, and biological production is higher
                             21

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and starts earlier there than offshore.  The offshore movement of
the bar continues until thermal stratification is established in
late June over the whole basin."
   Continuing with a description of the overall seasonal stratifi-
cation of the Lake, Dr. Mortimer states:
   "The form which the thermal stratification takes is determined
by the interplay of the buoyancy of the surface, heated water masses
and the mechanical mixing energy of the wind.  Typically the upper
layer (the epilimnion) is mixed to near uniformity down to about 30
feet (10 m) by the end of June, at which time the lower water masses
(the hypolimnion) has warmed up to approximately 4C.    The epilimnion
and hypolimnion are separated by a thermocline, a relatively narrow
zone in which temperature falls and density increases sharply with
depth.  The mean level of the thermocline gradually ^psrnnr|s Huring
the summer  but its actual  level  at any one time is strongly perturbed
by down-tiltinj (downwel1 ing) and up-tilting (upwelling) within  10
miles (16 km) of the shore  and by large internal waves occupying the
whole basin.   When the net  heat flux to the water surface becomes
negative at the end of August, the epilimnion cools and the thermo-
cline begins  to descend more rapidly, culminating in  a complete  mix-
ing of the water layers (the overturn) in December.  Subsequent  cool-
ing of offshore water during winter occurs  with a more or less ho-
mogeneous water column well mixed from top  to bottom, falling in
typical winters, to a temperature close to   2C  by the end of March.
Ice normally  forms only in bays, e.g. Green  Bay, and near the shore."
   Water temperatures at or near the surface respond  to daily insola-
tion, diurnal heating, and  cooling of surface layers.  During the
                                22

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summer, longer days cause a  net heat gain;  during winter,  longer
nights cause a net heat loss.   The temperature interaction at the
air-water interface also causes climatic modification  through over-
all  temperature mediation and  lake breezes.
     As stated earlier, the  winter minimum  in offshore waters of
Lake Michigan occurs in late March at temperatures near 2C.   The
shallow water near the shore is essentially  freezing temperature for
a period of approximately 3  months,  January  through March; however,
solar insolation may warm the  shallow water  to 1C - 2C for a  brief
period of time on bright winter days.  Surface water temperatures
may  reach highs of 18C to 21C  in mid or late August.  At any  time
during the year more than half of the water  in Lake Michigan  is  at
a temperature of 4C or less.
     Transparency
     In water, transparency  is the ability  to transmit solar, in-
direct, and artificial light.   Its effects  are felt on water
chemistry, biological  activity including phytosynthesis, circulation,
stratification, and materials  transport.  It is affected by color,
dissolved solids, and  suspended solids, and  the penetration is
determined by intensity at the surface and  angle of incidence with
the  water surface.  In other words,  the more turbid the waters  the
less the light penetration.   Further, accumulations of suspended silt,
organic materials and  other  particles around the periphery of
Lake Michigan, particularly  in the southern  basin, would lead one to
expect lower transparencies  there.  Short term variation might  be caused
by tributary inflows,  storm  activity, and plankton blooms.
     Seasonal variation is influenced by basin physiography and
                               23

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cultural development.  Mean transparency in late spring is highest
in the deeper portions of Lake Michigan with lower transparencies
near shore and in shallower northern portions.
General Chemical
     The chemical qualities of Lake Michigan are influenced by the
biota and sediment in the Lake in addition to contributions through
natural and cultural loads from run-off and tributaries.  Nutrient
loads have the greatest effects along with more general pollutional
loadings at the heavily industrialized southern portion of the Lake.
Water quality is complicated by the uncertainties of circulation, by
the great depths of the Lake and by relatively small out-flow from
the Lake which might ordinarily lead to a displacement of chemical
products.
     Natural Contributions
     These constituents are weathered products of soil and bedrock
along with organics derived from the biota.
     Cultural Contributions
     Materials that result from man's activities are e.ither associated
with run-off or are directly discharged into the Lake.  The major con-
tributions include agricultural wastes, industrial and municipal
wastes, and atmospheric fallout.    Nutrients, toxic metals, hydro-
carbons, pesticides, phenols and complex organics present problems
of great concern in  the management  of Lake Michigan.
     Dissolved Solids
     A  useful  index  of  the total natural and cultural  inputs  to  Lake
Michigan is total  dissolved content. Specific conductance is  a common
measure of the inorganic  dissolved  content, and surveys of conductance
demonstrate major  sources  in the Chicago-Gary area and disclose
                                  24

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maxima along the periphery of the southern basin.

     Chlorides
     This ion is conservative,  i.e.,  does  not readily enter into
chemical  and biological  reactions and may  therefore be used as an
index of  chemical  loading  and chemical  build-up yielding useful
comparisons with the behavior of non-conservative  material.
Chlorides originate from brines, road deicing,  industrial  compounds,
cleaning  compounds, and  natural  soil  and rock weathering.   Lake
Michigan  data indicate chloride  increases  from Chicago-Gary, to
Green Bay and Milwaukee, and reaches  from  Benton Harbor to Muskegon
and Little Sable Point to  Frankfort.   Major loading problems have
also occurred at Manistee  and Ludington from natural  ground water
concentrations there.

     Carbonates
     The  interaction of  water with carbon  dioxide  is  significant to
living systems of the  Lake due  to requirements  for C02 for photo-
synthesis.  A complex  equilibrium of  C02 in the carbonate  system
supplies  this necessary  ingredient.   This  equilibrium is controlled
by temperature, atmospheric C0p» pH  and associations  with  calcium
carbonate, CaC03.   Some  measurement  for the capacity  of the water to
support life are pH, alkalinity  and  bicarbonate.  The tendency for
change is counteracted by  the buffering capacity of the water and
the most  abundant mineral  in the Great  Lakes system which  supplies
this buffering capacity  is CaCO,.
                               O
     So far, there are insufficient  data to determine areal pH dis-
tribution in Lake Michigan.  In  addition,  there is some evidence that
rises in  Ph can occur  as a result of  algal photosynthesis  and may
                            25

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displace the C02/carbonate equilibrium to a point at which calcium
carbonate precipitates.
     Oxygen and Redox Potential
     Oxygen is also essential for life support and its solution into
the water depends upon pressure and temperature.  Parameters which
reflect oxygen and oxygen demand in the water are D.O. concentration,
Op activity, percent saturation, Biological Oxygen Demand, and
Chemical Oxygen Demand.  Redox potential  reflects the potential of
the environment to oxidize or reduce material.  Although oxygen
supplies in the Great Lakes have been thoroughly studied, Lake
Michigan has not experienced serious problems except at the southern
end of Green Bay.  Other data which reflect areal trends in oxygen
or redox potential are insufficient for comparison.
     Phosphorus
     This nutrient is essential in living systems, is readily recycled
and can be a factor limiting growth.  It  occurs in a number of forms,
predominately as ortho and poly phosphates, and it is removed from
lake water by organic sedimentation, by ion exchange on clays and
through uptake by algae.
     The assimilative capacity of the Great Lakes for phosphorus
is high due to their water volumes but continued loading leads to
local overproduction of algae.  Phosphorus removal is difficult and
control in Lake Michigan is by limitations on nutrient loading,
particularly from the sewage treatment plants discharging to the
Lake and its tributaries.
     Ni trogen
     This nutrient encourages eutrophication in excess, but many
                            26

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sources such as atmospheric and ground water inputs,are not readily
                                          * _. &    •"?•-""
controllable.   It occurs as free nitrogenv*'nitrate, nitrite and
ammonia, as well  as in most organic  forms.  The nitrogen cycle is
complex but well  understood.   Nitrogen is also assimilated rapidly
into the Great Lakes System but relatively high concentrations may
develop in nearshore areas receiving high loadings.

     Organic Compounds
     These compounds have the principal  effects as oxygen demanding
compounds and  as  toxic substances.   An attempt is made here to
introduce the  problems associated with those compounds as pollutants
while recognizing that recent control  measures have reduced their
seriousness to the Lake.
     Chlorinated  hydrocarbons are persistent, rapidly distributed,
and easily assimilated and magnified toxicants.  In Lake Michigan,
DDT accumulations in Coho Salmon were  determined to be unsafe for
human consumption by the Food and Drug Administration in 1969.
Discontinued use  of non-biodegradable  pesticides is a practical
control but physical-chemical interactions may tie up quantities
of these compounds in the environment, particularly in sediments
and degradation products.  A  serious problem area with respect
to chlorinated hydrocarbons exists  around Green Bay, Wisconsin,
but DDT levels in many fishes from  the open  lake were 2 to 5 times
higher than in other Great Lakes fishes  according to surveys.
     Polychlorinated biphenyls also  persist, are biologically magnified,
and are toxic  in  sufficient doses.   They have been identified from
industrial sources in the Great Lakes  and may be found in fish at
higher than acceptable concentrations.       ^.-
                            27

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     Phenols and phenolics are benzene derivatives which impart un-
desirable tastes and odors to water and edible biota, and which are
toxic in low concentrations.  Since they are biodegradable and non-
persistent, they cause problems only near their sources.
     Detergents add nutrients, usually in the form of phosphates.
These compounds indirectly reduce light penetration, and may be toxic
in quantity.  Since the  so called "soft detergents" containing
linear alkylate sulfonates are biodegradable, their current use is
less of a problem than the alkyl  benzene sulfonate fractions formerly
used.
     Petroleum can be a problem in lake waters by exerting oxygen
demand, by restricting gas exchange and by leaving unsightly slicks.
Lighter fractions may also be toxic.   A recurrence of oil spills
from shore installations and loading docks has been noted on Lake
Michigan in the Chicago-Gary area and has caused considerable con-
cern and study.
     Calcium and Magnesium
     These are the main elements  contributing to hardness and scale
formation.  Their presence in water results from leaching of lime-
stone, dolomite and other minerals containing calcium and magnesium
found in the watershed.  Calcium and magnesium ions are  major con-
tributors to the total ionic strength in Lake Michigan.  Calcite
and dolomite are important components of the carbonate buffering
system and Lake Michigan is essentially'at steady-state condition
with respect to calcium and magnesium.
     Sulfur
     Sulfur, important in protein synthesis and in hydrogen sulfide,
                                28

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sulfuric acid and its dissociation products, enters the system
through precipitation, ground and surface waters, industrial wastes
and domestic sewage.   The sulfidesadd disagreeable tastes and odors
and may be toxic to certain biota.
     Concentrations of sulfur compounds in the Great Lakes have been
rising in recent years.  Concentrations in Lake Michigan are greatest
in areas of limited circulation such as Green Bay and Traverse Bay.

     Silicon
     This constituent is  important as a nutrient for diatomaceous
phytoplankters,  as  an index of weathering of silica rocks and be-
cause of its reaction to  form sedimentary silicate minerals* This
"rate of reaction"  depends  upon residence time of water in the
vicinity of the  mineral,  composition and crystal structure of the
mineral, temperature  and  composition of the  water.
     It has been concluded  that the silicate system is  an active
buffering mechanism in the  Great Lakes.  Depletion of silica levels
in the photic zone  in the summer is attributed to uptake by diatoms.
     Iron and Manganese
     These compounds  are  important in the Great Lakes because of
their sensitivity to  chemical  changes, their buffering  capacity,
their function  in nutrient  removal, their toxicity to plant and
animal growth under certain conditions, their role as micronutrients,
the possible presence of  mineable manganese  nodules,  and their con-
tribution to taste  and color of Great Lakes  waters.
     Trace Elements
     When certain of  the  trace elements are  present in  sufficient
                                 29

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quantities, they can be toxic; all can be used to identify sources
of natural and cultural inflows.  Increased concentrations have
been measured within the upper few centimeters 'of the sediment -
water interface.  Trace metals inputs have been measured in major
tributaries to Lake Michigan.  Iron, copper, nickel, chromium,
and zinc are found in detectible quantities.  Cores from southern
Lake Michigan have indicated high concentrations of arsenic near
Benton Harbor and Grand Haven, Michigan and Waukegan, Illinois.
These concentrations are supposedly derived from pesticides.
    Barium, boron and bromine have not been found in Lake Michigan
waters in sufficient quantities to present a serious problem.
However, cadmium, chromium and copper have been measured in the
sediments of southern Lake Michigan in a wide range of concentra-
tions.
    Iodine in Lake Michigan was measured in quantities lower  than
in any other Great Lake.  Lead is concentrated in the upper sediment
layer and is presumed to originate from airborne particulate  com-
pounds.
    Mercury has been found in the Great Lakes in alarming quantities,
Sources  are clear-alkali plants, pulp and paper mills, electrical
industries and other public and industrial uses.  Metallic mercury
was discharged indiscriminately to the environment prior to the
middle 1960's under the assumption that it was relatively inert, but
methylation has been shown to occur.  These processes lead to con-
centrations in fish well above levels set by the USFDA and Lake
Michigan sediment cores contained concentrations from 3 to 8  times
that of the water over the sediment.
    Little is known of the concentrations of silver, selenium and
                                30

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the uranyl 1qn in Lake Michigan.  However, zinc was found in
quantities in sediment cores from the southern part of the Lake.
    Radionuclides
    Technological control of radionuclides has received  ample
attention since the hazards of raioactivity have been recognized.
Sources are limited, but small  additions accrue from atmospheric
fallout,  reactor waste disposal, and accidental reactor, in-
dustrial, and research release.
    Total alpha radioactivity i9 greatest on the Michigan side of
Lake Michigan but this is attributed to natural radioactivity.
Water from near Big Rock Point nuclear plant, at Charlevoix,
Michigan, has shown counts slightly higher than counts west of the
plant.

Biological Characteristics
    Clearly,  there is  little hope that this section of the
Report  can adequately treat the wealth of information on the bio-
logy of Lake  Michigan.  It is hoped, however, that by addressing
                                i
aspects; salient to the introduction of thermal  effluents, the more
       i
obvious gaps  in understanding wfll be emphasized, and it will spur
necessary biological investigations.  Floral and faunal  groups des-
cribed  here are the bacteria and fungi, invertebrates, algae and
fish.

    Bacteria and Fungi
    Routine field studies on bacteria and fungi of natural  waters
such as, Lake  Michigan are relatively rare in comparison  to studies
of higher biotic groups.   Problems in the biological and biochemical
                               31

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characterization of these natural populations have not been
solved due to  lack of adequate methodology.  However, many of the
chemical processes which comprise the major roles of these organisms
in the functioning of the ecosystem have been studied extensively.
     Bacteria  and fungi are decomposers, converting organic ma-
terial into simple inorganics which can be easily utilized by
heterotrophs and autotrophs alike.  Some bacteria are chemotrophs,
producing energy as a result of oxidation of inorganic compounds;
and yeasts often fill a vital consumer role.  Seasonal variation in
the nitrate concentration in Lake Michigan has been found to cor-
relate with changes in the rate of nitrification as well as the
uptake of nitrate by phytoplankton.  Specific decomposers such as
those with affinities for starch, chitin, or cellulose may be
scarce in areas of Lake Michigan at certain times.   Increases in
these and other bacterial populations may be closely dependent
upon the availability of surfaces (to which they may attach) in
the Lake and the fact that Lake conditions are often unsuitable
for the growth of aerobes from allochthonous origins. The variety
of yeasts in Lake Michigan has been related to sediment type with
evidence of only a slight relation to depth.
     One of the more outstanding problems in analysis of bacterial
and fungal populations from Lake Michigan is incubation temperature.
Although these microorganisms are typified by culture at 35C,  lake
temperatures rarely approach those conditions and a false estimate
of thermophils versus psychrophils may be obtained.  Other bacterial
increases may be closely linked with the availability of essential
nutrients and with the compounding effect of light penetration.
                               32

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     Lake Michigan is lower than Lake Erie in total counts of
bacteria used as indicators of sewage, with highest levels in
the southern periphery and in the area of Green Bay.  It has been
found that Lake Michigan waters are toxic to patheogenic enteric
bacteria such as Shi gel la and certain Salmonella organisms during
certain times of the year.  Toxins produced by Clostridium
botulinum are presumed to have caused large waterfowl  mortalities
in the Lake in 1963-64.
     Invertebrates
     Knowledge of the invertebrate forms of Lake Michigan is behind
that of Lake Erie and there are still major gaps in our understand-
ing of this important component.
     Although zooplankton are likely to  integrate environmental con-
ditions, their passive movements  through large water masses  make
interpretation of both quality and quantity difficult.   Early data
indicated no qualitative difference in zooplankton of  Lake Michigan
and this was explained by assuming homogeneous conditions in the
Lake.
     Various indices of  organic pollution have been developed using
benthic organisms which  seem appropriate in view of the  relatively
fixed nature of the group.  Insofar as fauna!  gradients  are  con-
cerned, oligchaete populations seem to be concentrated  in the
southern portions while  amphipods are more abundant in  the nearshore
zones of the more northerly portions.  Distributional  maps for pol-
lution-tolerant tubificids essentially correspond to locations of
larger cities on the Lake.
     Early data on Lake Michigan also indicate little  change in the
                             33

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species composition of plankton in the forty-year interval  prior
to 1926.  Recently a number of faunal additions have been reported.
It has been suggested that shifts in species composition may re-
flect the acceleration in eutrophication, but the picture is con-
fused by taxonomic difficulties.
     Attempts have been made to generalize regarding possible cor-
relation of Lake Michigan benthos with depth, but this has  been
difficult due to the variation in sediment deposits and sediment
types.  It would seem certain that the combination of substrate type
and exposure to wave action exert considerable influence on the
quantity and quality of these invertebrates, but organic content
is also a significant factor.  Temperature is also of importance in
several ways:  as it is affected by depth, as it changes with
season, and as it is increased through human activity.

     Algae
     Benthic algae seem to be of lesser importance in the Great
Lakes than periphytic algae, but euplanktonic forms are more
diverse and greater in biomass.  The Great Lakes flora consists of
a great number of species of phytoplankton and so considerable
difficulty exists in taxonomic discrimination.
     Nuisance algae has been used as an indicator of a decline in
water quality 1n Lake Michigan.  In the period, 1967-1970,  both
Cladophora and Spirogyra caused problems by windrowing on the
beaches, by creating odor and color problems, by creating un-
sightly conditions, and by fouling fishermen's nets.  Cladophora
and certain diatoms have also been blamed for taste and odor
problems and for clogging filters of public drinking water  supplies,
                             34

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but these seem to have been  transient problems  not in current
evidence.  Various other forms  have been indicated in the produc-
tion of algal  toxins  which  cause sickness  and death in waterfowl
and fishes and which  are capable of affecting mammalian populations,
     Various types of indices  to compare species and abundance have
been applied to the Great Lakes.  As might be expected, it has been
found that Green Bay  and a  near shore Lake Michigan site were more
eutrophic than another Lake  sampling station.
     The timing of planktonic  pulses appears  to exhibit differences
between southern, more northern and mid-lake  areas in Lake Michigan.
Regional  differences in species have been observed and the thermal
bar has been shown to exert  a  profound influence on planktonic
abundance.  In addition, spring phytoplankton standing crops were
higher on the   shoreward side  of the thermal  bar than on the lake
side with the  greatest standing crop at the thermal interface of
the bar.
     Evidence  of long-term  trends of phytoplankton standing crop
taken from Chicago filtration  plant records indicates an increase
in phytoplankton over the years, but evidence of taxonomic shifts
are ambiguous.  Some  species  are apparently declining and invasion
by new species, some  of a nuisance variety, has been described.
     Seasonal  patterns of abundance are considered bi-modal in
Southern Lake  Michigan with,  as has been mentioned, some variations
in timing in other lake areas.   In one study, it was concluded
that the major influences on  spring pulse  are temperature and
                             35

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turbidity and that fall maxima are more limited by chemical  and
physical factors.  In another study, primary pulse impetus has been
attributed to temperature alone.   Other workers have expressed doubt
that temperature alone can be simply correlated with phytoplankton
pulses and have attempted to relate nutrient distribution to these
phenomena.
     Patterns of abundance in phytoplankton have been attributed to
a number of factors including nutrients, phosphorous, nitrogen and
carbon.  Since the photosynthetic process and the rate of growth
are highly dependent on temperature and light, these factors must
also be woven into any scheme which presumes a limiting factor.
It is abundantly clear that temperature and light effects are
difficult to separate in analysis of field investigations of
phytoplankton.
     Fish
     Commercial and sport fisheries have probably taken place on
the Great Lakes since the arrival of man to its shores, but  the
nature of the lakes has permitted a profound effect to take  place
due to man-caused disturbance.  Changes in species composition and
abundance have been observed in all the lakes, but particularly in
those most closely influenced by  population and urban growth.
     The large sizes of the lakes have not encouraged an adequate
understanding of the distribution and population of resident
species so that, in many cases, historical trends are difficult to
deduce.  In addition, current records are derived from commercial
catch records which do not provide data on certain important groups,
especially, forage fishes.  The openings between the lakes permit
migration, in general, but passage through the St. Lawrence  River
                               36

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allowed Invasion by essentially foreign species and man has per-
mitted and encouraged the introduction of other exotics.
     Salmonids have largely dominated in establishing goals for
management of fisheries  of the lakes, including lake trout, the
coregonines and more recently the Coho and Chinook Salmon.
     Other introduced fishes significant to the development of
current lake conditions have included:  the smelt, carp,  and gold-
fish, the alewife, sea lamprey and white perch.
     In Lake Michigan, commercial fishing practices probably account-
ed for the decline of the lake sturgeon.  Other changes seen in
commercial activities are the decline in the lake herring,  whitefish,
lake trout, and the  increasing  appearance of smelt and  alewives.
The decline in trout and whitefish is jointly attributed  to preda-
tion by the introduced sea lamprey and by fishing; the decline in
lake herring is attributed to overfishing and competition by smelt
and alewives; decline in the chub fishery and changes in  the species
composition have been attributed to overfishing and alewife
competition.
     Fish are excellent indicators of environmental conditions;
both species composition and abundance reflect an integration of
cyclic and spatial environmental change; hence the environmental
interest  in fish.  Unfortunately changes in the fishery  do not
separate direct causes from indirect causes such as those resulting
from preemption of shallows and nursery grounds, commercial and
sports fishing, damming spawning tributaries, increased sedimentation
from agriculture and deforestation, and those wrought by the intro-
duction (however,  inadvertent) of predator and competitive  species.
                             37

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It has been, in addition, of insufficient interest, or at least
very difficult to obtain and keep adequate records of fish distri-
bution and abundance to facilitate the recognition and prediction
of fisheries trends.

              Summary of Outstanding Features

1.  It is the sixth largest freshwater lake in the world.
2.  It is extremely deep, with a mean of 276 feet (84 m)  and a
    maximum of 923 feet (281 m).
                            i
3.  It has a relatively small  proportion of shallow waters.
4.  It is relatively regular in outline.
5.  It has a relatively small  drainage basin.
6.  Aside from the peripheral  waters, particularly in the southern
    basin, and the waters at Green Bay, its transparency  is  high.
7.  It is a relatively infertile lake and might be classsified
    as somewhere between oligotrophic and mesotrophic.
8.  Detention time of water in the basin is extended.
9.  With some notable exceptions, the quantity of accumulated
    knowledge regarding the  lake ecosystem is relatively small.
10. Lake Michigan is lower than Erie, but higher than Superior and
    Huron, in fish productivity and species composition and  the
                                                          i
    fishery has been greatly influenced by man both directly and
    indirectly.
                             38

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                    Use of the  Resource

     The 13.5 million people  of the  Lake Michigan Basin (including
the Chicago Metropolitan Area)  have  at their  disposal  a resource
of magnificent dimension; it  is an  "inland ocean" of drinkable
quality.  In 1970,   over 2,000  mgd  of water were withdrawn from
Lake Michigan for municipal  use;  that is projected to increase
nearly 500 mgd by 1980.  Barring  further degradation, over 1,100
cubic miles of drinking water are available.
     Excepting the  coldest months of the year,  waters of the
Great Lakes are widely used  for shipping; in 1972, that amounted
to over 200 million tons of  cargo,  largely landed at or near
Chicago.  Much of this was iron ore, limestone  and coal transported
from Lake Superior  to the steel mills of Gary-Hammond,,
     Other uses include sport fishing, boating, swimming, and bird
watching.  In Chicago and Milwaukee  the lake provides a pleasant
setting for the urban background  and permits the inhabitants an
escape to open space.  During warmer h.onths, the shores of the Lake
are widely used for biking, walking, swimming,  and visual relief.
     The Lak." mediates domestic sewage and industrial wastes and
these introductions  probably have  had greatest impact  on the
other uses.  The effects are  felt largely in the peripheral  areas
of the Lake since economics encourages disposal close to shore.
It is also true that the littoral  zone is ecologically  of greatest
                                                            i  -V"»
value and of  greatest concern  in protection of drinking water
quality.  Treatment at municipal  sewage plants  around the lake in
the 1970's was in excess of 660 mgd  with capital costs  exceeding
350 million dollars.  These costs may double by 1980, and operation
                            39

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and maintenance is rising,,  Industrial wastes, largely in the
southern basin, are unestimated but contribute substantially to
water quality problems.  Lake waters are also used to mediate
the effects of waste heat produced in the process of electrical
generation.  Power demands from both the domestic and industrial
sectors in the future will probably increase pressures for this
use.
     Lake Michigan also has an important role in the total commer-
cial fisheries catch of the Great Lakes Basing  Preliminary data
indicate that 47.4 million pounds, worth 5.2 million dollars were
landed in 1973.  These landings account for 76 percent of the
total weight taken in the U.S. Great Lakes and 61 percent of the
dollar value with the discrepancy between percent weight and
percent value explained by alewife harvest.
                             v
     Sports fishing in the Great Lakes has increased in value,
due in part to massive stocking programs of state and federal
agencies, to an estimated 350 million dollars per year (not
including capital equipment), with the value in Lake Michigan
estimated at 73 million dollars per year.   These numbers are
estimated due to the difficulty in determining the value of a
resources so highly dependent on services of a diverse nature,
such as the fuel, baits, lodging, food, boats and equipment,
required to participate in the sport.

                        Basin Growth
     The total Great Lakes Basin population accounted for 14 to 15
 ^Personal Communication, 1975.  Great Lakes Fisheries Commission,
  Ann Arbor, Michigan,
                            40

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percent of the U. S. population in the decades 1940-60 with  the
Lake Michigan Basin containing 46 percent of that total  during
the same period.  In the decades 1980 to 2020, this Basin  total
is projected to decrease slightly to 13.5 percent of  the national
by 2020 with Lake Michigan maintaining a relatively steady 45 to
46 percent.  Absolute numbers in the Lake Michigan Basin are ex-
pected to increase nearly threefold (U. S. Army Corps of Engineers,
1972) and this addition will cause water uses to increase.   Ex-
tended concern for the well being of the Lake is anticipated.
             Correlation of Basin Growth to Basin Uses
    Development of data which would indicate trends of water or
lake use is difficult.   Increases  (from 1940 to 2020) from ap-
proximately 8.5 million to  nearly  25 million total  Lake Michigan
Basin population can be surmised to add to uses of the Lake for
recreation, domestic consumption and for waste disposal.  Certain
aspects  of use  for transportation  might also increase but would
require  a detailed breakdown of  cargo.
    Employment  projections  indicate that the total  workers in
the fields of agriculture,  forestry and fisheries will decrease
from 267,216 in 1940 to 49,700  in  2020, repeating a decrease of
81 percent.   For workers employed  in manufacturing industries,
projections are for  1,085,201 workers  in 1940 to increase  149
percent  to 2,705,000 workers in  2020.   Clearly, since these are
projections and since the respective impacts of these jobs are
not known, these number's must be used with caution.
    National  trends of surface water use for recreational activities
are increasing.  This is due to  the increased urbanization of the
                               41

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population and a tendency to desire escape or change, along with
an Increase In leisure time due to a shortened work week.  This
indicates that water quality must continue to be upgraded for
water contact, and that management of fisheries must take sport
fishing into greater consideration than has been done previously.

              PROBLEMS RESULTING FROM INCREASED USE
                 Conflicts of Multi-Use Concept
     Designation of a water body for multi-use either formally
or informally means that the most stringent water quality demands
must be met on a total basis.  For Lake Michigan, use for drink-
ing requires that the water be oil and grease free, that organisms
which might impart unacceptable tastes and odors be absent, that
organisms which would clog filters be absent, and that bacterial
levels be acceptably low.  The level of required quality for use
of Lake Michigan waters for industrial processes, for waste
disposal, for shipping, or for power boating are rather low and in
fact, these latter purposes are likely to contribute to poor quality
unless controls are exacting.  The possible conflicts between
these intended uses can be great.
     This is especially true in a water body like Lake Michigan
with its oligo-mesotrophic characteristics of cold, transparent,
relatively infertile waters.  The conflict becomes exaggerated
since the human population which aesthetically desires transparent
                                        i
blue water causes the lake to attain a progressive degree of greenness
merely through its existence on the shores.  Furthermore, the
Lake is most green within sight of shore and more pristinely
                             42

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blue nearer the center of the Lake,  out of sight and reach of the
majority of the inhabitants.
     The simplest answer is to insist on maintenance of the entire
Lake at a level of quality appropriate to all  uses.   Such
uniformity cause it to be most easily monitored and  regulated,
and certainly most acceptable for the variety  of uses,  but it is
also clearly the most expensive.   It may even  be an  unwise use
of the resource.  The alternative of zoning or use designation
where controlled disposal or use for shipping, for example, may
be limited to certain areas, is a possible answer, but this
solution is not in consonance with the national trend to clean
up our surface waters.  It is also more difficult to monitor and
regulate, and by natural forces, difficult to  control and limit
the areas of effect.  However, it may be more  in keeping with
the notion of wise use in contrast to the purest conservation.
     It is not the purpose of this document to rule or decide on
these questions, but rather to discos them.  The technical
expertise available to us, as a nation, may, in fact, permit us
to understand what are the costs, the techniques, and the efficacy
of a return of this Lake to a "blue or a greenish color" but it
is a social decision as to what that color should be.  It is
worth noting that this is a group decision and not one for a
select few, whether they are scientists or informed citizens.
                          Eutrophication
     In the current ecological movement, the term "eutrophication"
has been widely used to mean a deterioration in water quality
and excessive productivity due to man's activities.  In a
                                 43

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scientific context, it  is  a term describing the aging process
undergone by all  lotic waters.  Scientifically, it has been used
most extensively  in  reference  to small upland lakes; this con-
tinuum of aging has  been  designated  by three terms and charac-
terized as follows:
     1.   oligotrophic -  deep, abundant oxygen, low
          nutrients, few  individuals of the biota
          from a  large number  of taxa.
     2.    mesotrophic - characterized similarly but
          with an increase number of individuals  of
          the biota from a decreased number of taxa.
     3.    eutrophic - shallow, lower oxygen (especially
          at depth), high nutrients, large numbers of
          individuals from a relatively few taxa.
     Lake Michigan is certainly undergoing these  changes  in the
process of aging, but the vast quantities  of water involved
tend to slow the process.  The lake' s depth provides a buffer
against the tendency to become more shallow,  and  the great water
mass resists seasonal warming, and dilutes the effects  of
nutrients that cause increase in productivity.   It is probably
true, as mentioned previously, that the more peripheral,  littoral
waters in the southern basis of Lake Michigan  are exhibiting the
symptoms of eutrophy and this is more certainly true in Green
Bay.  This is primarily caused by land run-off and contributions
from smaller municipalities, and in the southernmost part of the
Lake,to industrial discharge.  The limited literature suggests
that subtle, though not necessarily irreversible  degradation of
the Lake has already taken place; retardation  of  these  processes
is a desirable end.
                                   44

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                     Literature Cited
Beeton, A.M.  and D.C.  Chandler.  1966.   The St.  Lawrence
     Great Lakes.   Pages 535-558 In;   Frey, D.G.  (ed)
     Limnology in  North America.  University of Wisconsin
     Press, Madison,  Wisconsin.

Great Lakes Basin  Framework Study.  1972.   Limnology of
     lakes and embayments.   Appendix  No.  4, Draft No,.  2,
     Volume I (Parts  I and  II).   Great Lakes Basin
     Commission, Ann  Arbor, Michigan   658 pp.
                          45

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                   SECTION II



DATA REQUIREMENTS RELATED TO LAKE MICHIGAN STUDIES

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Section II.  DATA REQUIREMENTS RELATED TO LAKE MICHIGAN STUDIES

                       TABLE OF CONTENTS
Introduction 	    49
Declaration of Intent	50
Sampling Considerations  	    51
Sample Collection and Processing 	    55
Data Handling	61
Data Evaluation	62
Scientific Acceptability .........    66
Introduction to Priority Needs   .    	    69
Priority Needs   	    70
Literature Cited 	    .73
                               48

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Section II.   DATA REQUIREMENTS  RELATED TO LAKE MICHIGAN STUDIES

                        Introduction

     This section of the Report presents recommendations toward
the objective quantification of the effects of cooling water use
on surface waters.   Many environmental studies have suffered from
insufficient statistical confirmation of ecological conclusions.
This can best be remedied by more thorough statistical planning
during early stages of program  design.  Objective statistical
support of ecological  conclusions can be achieved through adequate,
informed planning of the number of stations, intervals, frequency,
and replicates.   Suggestions are also made regarding study design,
data collection  and some fundamental statistical  analysis.
     Concern has also  been expressed with the great amount of
data on Lake Michigan  which are scattered widely  in formal and
informal publications  and accumulated in files unavailable for
comparison and analysis.  Lake  Michigan investigators are
encouraged to make  all Lake data available for review and analysis
through central  data storage.   The answers to many current
questions regarding the ecological status of the  Lake lie within
reach through data  which have  already been collected; this
section of the Report  proposes  efficient utilization of those
data.                 •
                            49

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                    Declaration  of  Intent
     It is important to define the goals of each proposed
research project and the relationship of that project to the
overall goals of assessing the effects of cooling water use.
This should be accomplished in a written proposal of study prior
to actual  data collection.  Such proposals should be carefully
developed and closely scrutinized by the funding agency, since
it serves as a basis for both the quality and the usefulness of
the proposed work.  Submission of the proposal  to the funding
agency should be preceded by a critical  external review by
colleagues and other professionals to increase  utility of the
study.
     Collection of data on each environmental parameter should be
justified.  The collection of data and samples  "which might be
useful later on" can be very compelling.  Clearly, data collec-
tion can save time, effort and money as  long as future use is
not only anticipated, but is an integral part of the program plan,
The collection of data and samples with  no planned purpose should
be discouraged.
     The types of measurements which should be  made are defined
in later sections by suggesting standard techniques for the
subject organisms or parameters.  A study proposal should include
a detailed description of the type and desired  precision of those
measurements selected, with justifications.  In addition, the
study area and areas of concentration and a rationale for those
limits should be indicated.. The duration of the research project
should be stated with some realistic estimate of the possibility
of meeting target dates.
                                50

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                   Sampling Considerations
     After problem selection,  an explicit statement of that
problem should be drafted to relate the proposed sampling scheme
to it.  For example,  if an attempt is made to determine changes
in water chemistry caused by the introduction of heat, the
possible reasons for  an expected change should be stated, based
upon the physics of the system and the chemicals in question.
Sampling plans should provide  details of suspected spatial and
temporal changes (or  differences) and the manner in which these
will be statistically quantified so as to leave no reasonable
doubt of the magnitude of Qhange (or difference).  Extensive
and statistically sound use should be made of reference locations
and times.
     After the problem is defined and the measurements are
selected, the associated assumptions must be made and clearly
stated; for instance, it could be assumed that release of biocides
into a cooling water  discharge is not time dependent, i.e.,
with neither diurnal  or seasonal variation,  since power plants
operate more or less  continuously.  These assumptions affect the
economics of the proposed work to a great extent; sampling may
be conducted during working hours and in seasons of comfortable
ambient conditions.  If later  information indicates that plant
operators apply reduced quantities of biocides in winter months
when fouling of the coolant system is less likely, or should
biocides be applied at specific daily periods, the statement of
these assumptions become valuable.  They may cause data to be
discarded  or  at very least,  reevaluated, and effect new
experimental design.   Further, and perhaps most importantly,
statement of the most trivial  assumptions forces the investigator
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to more critically examine the precise nature of his problem
and proposed methods of investigation.
     Prior to the problem statement, a review should be con-
ducted of existing data and studies which bear on the proposal.
This should be done in a form suitable for publication.  Should
previous data or studies be unavailable, a modest pilot study
should be conducted to develop information on which to base an
informed proposal.  Both literature reviews and pilot studies
are used for justification of the proposed studies, for forming
a data base upon which to build, to serve as a source of
appropriate techniques, methods and tools (including statistical
considerations) for comparison with new data, and as an indication
of careful proposal preparation.  The intent of both literature
survey and pilot study is to estimate the magnitude of central
tendency and the magnitude of variation of each parameter,  and
to determine the potential  for discrimination of environmental
differences.
     In its final form, the sampling design should  reflect  the
full range of each parameter, to differentiate human influences
from natural variability due to climatic, seasonal, daily and
other periodic and aperiodic changes.   This necessitates random,
or other statistically sound sampling.  Replication and the
provision of reference data, reference samples and  reference
stations are also required.  The number of replicates needed for
statistical treatment is dependent upon the variation in the
parameter of interest, the accuracy with which one  desires  to
describe the parameter and the magnitude of difference one  desires
to detect (See Cochran and Cox, 1957).  Careful  selection of this
                                 52

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number will  assure a sound comparative base without collection
of excessive or redundant data.   The number of replicates need
not be regarded as fixed but rather subject to adjustment on the
basis of periodic review and analysis.
     In cases where the number of replicates required for
statistical  validity is too great due to economic or physical
limitations, the desire for statistical  acceptability must be
balanced against practical considerations.   The investigator
must also consider if:
     (a)   the question is valid,
     (b)   the question is sufficiently  important to
           justify possible upheaval  in  the subject
           population,  and
     (c)   the effort and expense which  the investigator
           must expend  to achieve statistical  validity
           are warranted.
     To serve these desired ends, benefit/cost analysis  may be
appropriate.
     When these costs,  both economic  and environmental,  have been
balanced, the information and  measurements  may be designated as
"special studies" for intensive  investigation  at  a single site.
When this occurs, the investigator should select  a site  with
broad characteristics that could  apply to several  sites  or to  an
entire system.
     Although the emphasis in  this section  of  the Report is
toward meeting satisfactory statistical  goals, it should be noted
that statistical  significance  does not imply ecological  signifi-
cance and vice versa.
                                  53

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     The proper order for development of the statistical
rationale should be:
     (1)   observation or proposal  of a change or
           difference,
     (2)   preparation of an hypothesis which is a
           statement of that change or difference,
     (3)   preparation of a test for that hypothesis
           which would tend to verify the existence of
           change or differences and would establish
           their magnitudes,
     (4)   preparation of a statistical framework for
           the test which verifies  that observed
           differences are not due  to random chance and
           which establishes the probability that the
           changes or differences in collected samples
           reflect actual changes or differences in the
           environment,
     (5)   review of tests and statistical requirements
           to determine feasibility within physical,
           biological, temporal, and spatial constraints.
     It is clear that the state of  knowledge of organism  groups
and the available investigative techniques and tools strongly
influence testing, sampling, and the ability of the investigator
to draw conclusions regarding ecological significance. Any
ecological significance perceived should be declared, with
specific limitations of the tests.
     The great number of variables  in the lake makes the  attain-
ment of true ecological "controls"  virtually impossible.   However,

                                 54

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this does not preclude the demonstration of meaningful  differences
between areas of suspected effect and reference stations.
Reference stations might be considered sampling locations  at
which measurements are made which typify natural  or ambient
conditions in a given time and space.
     When the decision has been made to collect data, a sampling
schedule should be developed to facilitate field  study.
Frequently, biological data are separated from physical, chemical,
geological and meteorological  data due to the relative  difficulty
of collection.  In many cases, the measurement of biological
parameters in situ is not possible,  and laboratory time may be
greater than field collection  time by a factor of 20.  Therefore,
it is usually easier to collect chemical and physical in situ
data which more accurately reflect ambient conditions,  and there
is a reluctance to collect biological data simultaneously.
However, biological, chemical  and physical data should  be
collected concurrently insofar as is possible.
              Sample Collection  and  Processing
     The absence of comparative data is frequently a major
problem in environmental  study.   Regardless of the nature  of the
study, temporal and spatial changes, rates and instantaneous
magnitudes are measured only against data collected expressly to
provide background.  Data collected  for other studies are  rarely
directly comparable to proposed work for one or more of the
following reasons:
     (1)   the time frame is not comparable; e.g.,
           previous data were  collected in winter,
           or during the night, or were not collected
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           with the desired frequency;
     (2)   the location is not comparable; e.g.,
           previous data were collected two miles
           further from shore, only at the surface,
           or were all collected across the Bay which
           has been filled in with dredging spoil;
     (3)   unusual ecological conditions prevailed
           during the previous collection that cannot
           be duplicated; e.g., mean temperatures
           exceeded the 20 year average, flows exceeded
           the 100 year expected high, or water level
           was less than the predicted lows for that
           water body.
     These variations are usually impossible to control and dif-
ficult to predict.  However, some variation in design and data
collection can be standardized through agreement.  This sub-
committee recommends careful review and standardization of the
following wherever possible:
     (a)   Collecting gear and other equipment
           This includes nets, seines, dredges, pumps,
           water samplers, traps, and instrumentation
           and pertains to overall dimensions, orifice
           sizes, net apertures, rates of water
           passage, sizes and location of supporting
           structures, and methods of suspension and
           deployment.                                        •
     (b)   Techniques of collection, processing, and analysis
           This includes methods of cal ibrat.ion; field collection
                                56

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     period,  distance,  or  volume;  sequence  of  deployment,
     sample  removal,  gear  cleaning,  sample  sorting,  sample
     treatment  and  preservation, and  sample  storage;  lab-
     oratory  sequences  of  sample removal, washing,  treat-
     ment, examination,  sorting, enumeration,  and
     recording;  and a basic  series of  analyses which  may
     be  applied  to  the  data.
(c)   Reference  collections of  permanently preserved  samples
     which are  entire,  or  aliquots representative of  the
     original sample
     This  requires  specification of  storage  facilities
     recognized  by  investigators for  routine deposit  of all
     preservable field  samples.  These reference collections
     permit  examination, identification, emuneration  and
     analysis subsequent to  the original treatment,  for
     confirmation of  the original  results,  or  to permit
     application of analyses not considered  at the  time c ;•
     original treatment.
(d)   Standard and accepted biological  keys
     This  presumes  that, (1) texts exist which permit
     organism identification through  comparison with  a
     series  of  recognized  characteristics,  and (2)  that those
     characteristics, organisms, and  keys have the  sanction
     of  authorities in  the field or  discipline, and  have
     applicability  and  the desired accuracy  for use  in a
     limited  geographic  area.
                           57

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(e)   Methods and forms for reporting
     Development of recognized and accepted forms  for field
     and laboratory data recording permitting immediate
     transfer to computer/storage and processing.
(f)   Units for reporting environmental  data
     Metric units are preferred for all  parameters;  English
     units are included in this report  as  supplements to
     metric units only where they were  collected  in  earlier
     studies.
(g)   Accuracy of reported data (i.e., significant  figures)
     Precision should meet the objectives  of the  project
     for which the measurements are being  obtained.   When
     limitations to precision are built  in, as in  the use
     of instruments that are calibrated  to, for instance,
     the second decimal place (0.01), there is no  advantage
     in attempting to interpolate between  the lines  nor  is
     there reason to read multipliers of that second decimal
     place to an accuracy greater the'  that which  is real  or
     justified.
(h)   Horizontal positioning and mapping
     Measurements of distance are used  in  nearly  all phases
     of environmental sampling and monitoring.  In general,
     the greatest accuracy is required  for mapping horizon-
     tal distances for locating discharge  plumes  and
     obtaining accurate current measurements.  Systems
     for obtaining distance measurements with varying degrees
     of precision are readily available.  Methods  of de-
                             58

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     termining  distance  should  be  routinely  reported  with
     the  precision  of  the  instruments,  and where  appropriate,
     with  the observed  variability  of repeated  measurements
     of  the  same  distance.

     As  a  special case,  the  location of the  near-field  iso-
     therms  to  thermal  discharge structures  dictates  that
     the  position of the temperature measurement  be  known
     with  an accuracy  of no  less than 10 percent  of  the
     width of the discharge  orifice.  For geometrical  reasons,
     the  error  in position will always  be equal  to or greater
     than  the error in  the distance measurements  that define
     that  position.  Therefore  the  maximum error  for  dis-
     tance measurements  when  mapping the near-field  region
     of  the  plume should be  about  5 percent  of  the width of
     the  discharge.

     In  trapping  the far-field  region of the  plume, accuracy
     of  position  is less critical.  Inaccurate  distance
     measurements will  produce  inaccurate areal  measurements
     within  isotherms  but  the  major source of  inaccuracy
     results from the  artistic  freedom  assumed  in drawing
     isotherms  through  widely  scattered data points.
     Accuracies  of  +_ 10  to 30  meters are reasonable  in
     mapping far-field  regions  of  the plume.
(1)   Vertical distance
     Depth is usually  measured  relative to the  water  surface
     elevation  at the  time of  sampling  but,  in  some  instances
                           59

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     a fixed vertical  distance should be used.   For example,
     accurate depths are essential  in studies involving physi-
     cal  effects such  as erosion, sediment deposition or
     organisms on the  bottom of the Lake.   The  precision
     for  depth measurements for most studies is +_ 0.5 m
     (+_ 2 feet), but studies in the beach  zone  require pro-
     portionately greater precision.  A precision of +_ 0.01 mm
     (+_ 0.25 inches) or better may  be required  for studies
     of erosion or sediment deposition.
(j)   Level  of statistical significance
     Five percent, unless otherwise justifiable.
                             60

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                       Data Handling

     Modern computers permit investigators to collect and analyze
large amo.unts of data.   In a system as large as Lake Michigan,
and with investigators  widely  scattered in academic and govern-
mental  institutions, universal  access  to data collected on the
Lake is imperative.   Data released by  a scientist subsequent to
collection, computation and even publication should be placed in
recognized, accessible  storage  for possible use by others.  Thus,
the original  collection becomes even further justified, redundancy
is decreased  and conclusions regarding the environmental  state of
the Lake become more widely known.  In view of recent national
constraints regarding access to data collected through public
funds,  sharing may be mandatory once the information is released
by the  original investigator.
     Universal access to  shared data requires development of a
compatible format for collection and storage among investigators
and institutions of Lake  Michigan.  In addition, provisions should
be made for translation and transfer of data and analyses
packages between different computer systems.
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                     Data Evaluation

     In the section of the environmental proposal  or report des-
cribing material and methods there should be a statement of
minimum acceptable standards for data treatment.  This state-
ment should express not only the form for data presentation
(e.g., the arithmetic mean, the median, standard error, etc.),  but
should also state confidence limits acceptable to  all  investi-
gators and describe the statistical treatment in detail.  This
initial commitment will permit the reviewer to judge the rigor
with which the data were or are to be evaluated and will provide
the investigator with some targets at which to aim.
     When describing the effects of environmental  difference or
alteration, numerically, through species counts, biomass estimates,
or density, or when physical or chemical values are stated, the
following values should be presented, using data transformations
when appropriate:
               (1)  arithmetic mean,
               (2)  standard error.
               (3)  sample size, and
               (4)  confidence limits for the mean.
     Reference to these values and other statistical procedures may
be found in Snedecor and Cochran, 1967; Sokal and  Rohlf, 1969;
Steel and Torrie, 1960; and Zar, 1974.  In circumstances where
nonparametric analysis is appropriate, the investigator should
present the median, sample size and nonparametric  measure of
di spersion.
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     When describing  the  effects  of environmental  difference  or
alteration through  an evaluation  of the structure  of the  biotic
community, the following  forms  of expression  are  appropriate:
     (1)   species  diversity,  with the  specific  form dictated
          by convention of  the  biological  group (see Dorris
          and Wilhm,  1968;  Lloyd, Zar,  and Karr,  1968;  Pielou,
          1966),
     (2)   equitability indices  (e.g.,  "evenness";  see Pielou,
          1966),
     (3)   species  richness,  an  indication  of  the  number of species
          accounting  for  a  specified portion  (e.g., 95  or 99  per-
          cent) of  the community.
     The  results  of a study  of  suspected environmental  alteration
or difference should  be evaluated to determine  the extent of
difference, and to  determine  statistically whether the  differences
observed  are greater  than those which  could reasonably  be expected
to have occurred  through  random variation.
     For  an assessment of spatial and  temporal  differences,  the
following statistical procedures  are recommended:
     I ne  procedure  known  as  "analysis  of variance" is a widely
applicable method  of  statistically analyzing  lake  data.  By
analysis  of variance  one  may, for example, infer  from samples
taken at  different  locations  (or  times) whether the lake  means
at these  locations  (or times) are the  same or different.
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     Strictly speaking, analysis of variance requires certain
mathematical assumptions (e.g., an underlying normal  distribution
of data) be met, although moderate departures from these assump-
tions are not serious.  Howeyer, there are many cases where such
departures from the assumptions of normality are not  only pre-
dictable, but may be corrected for by transforming the raw data.
This is the case when dealing with percentages or with frequencies,
for example, in counts of biological entities.  Therefore, data
transformations should be considered wherever appropriate.
     If the transformation of data does not correct for severe
violations of the statistical assumptions for analysis of variance,
then techniques of non-parametric statistical analysis should be
considered to answer questions regarding spatial or temporal
differences in the lake.
     Following analysis of variance, multiple comparisons are
often desirable when more than two means are compared.  Procedures
commonly employed are:
               (1)  Student - Neuman - Keuls' test,
               (2)  Tukey's test,
               (3)  Scheffe's test.
     Similarity indices might be used to indicate uniformity  of
biological assemblages between season or area (Grieg  - Smith, 1964;
Horn, 1966; Whitaker, 1967).  Cluster analysis may also be utilized
to indicate similarities among biological assemblages (Cairns and
Kaesler, 1969, 1971; Cairns, Kaesler and Patrick , 1970; Kaesler
and Cairns, 1972; Kaesler, Cairns and Bates, 1971; Roback, Cairns
and Kaesler, 1.969; and Sneath and Sokal , 1973).
                                   64

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     Interrelationships among biological  and physical  parameters
may be examined by simple or multiple regression and coefficients
of correlation.
     In the visual presentation of data by tables and  figures,
planning and clarity of expression are paramount.  It  can also
help to have the aid of someone trained in graphics or with a
practiced eye for visualization.   Tables  should be fully self-
explanatory and the units for each numeric variable should appear
on each table or group of tables.   When measures of central
tendency are depicted in tabular  form they should be accompanied
by an indication of sample size and a measure of variability (e.g.,
standard error).  Where numerical  entries are zero, they should
be explicitly written rather than  indicated by a dash  or a dotted
line, and a numeric entry should  never begin with a decimal point.
     Figures should also be self-explanatory and should tend to
clarify data trends rather than to confuse or complicate them.
Overcrowded graphs and figures cause the  reviewer to lose
interest and perhaps miss a major  point of emphasis.  Both verti-
cal and horizontal scales should  be clearly labeled (including
units of measurement) on all figures or groups of figures and
samples sizes should be identified.
                                65

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                       Scientific Acceptability

     It is apparent that, faced with serious gaps in basic infor-
mation, it is neither possible nor desirable for the Lake
Michigan Cooling Water Studies Panel to compose "cookbook" or
pro forma exercises which would result in approval  to discharge
heat into Lake Michigan.  A more fruitful approach  is to cast
recommendations in the form of criteria of performance.   Such
criteria are common to all scientific investigations and rest on
the following points:
     Adequacy        -  Is the investigation of sufficient scope
                        and intensity to answer the questions
                        posed?
     Reliabi1ity     -  Does sampling and measurement quantify
                        answers with a degree of certainty which
                        would support meaningful conclusions?
                                           t
     Accountabi1ity  -  Will basic measurements and determinations
                        stand inspection by independent  experts?
     V a 1i d i ty        -  Do the measurements actually relate to
                        the quantity sought and are they indepen-
                        dent of other variables?
     Following is a further elaboration of these points:
Adequacy
     Clearly, the adequacy of studies is crucial in determining
effects of thermal pollution on biotic communities  in Lake
Michigan.  In simplest terms, several desirable or  undesirable
consequences may be envisioned:
                                66

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             1.   extirpation  of native  populations  through  intol-
                 erable habitat modifications,
             2.   introduction of exotic populations  through
                 modification of existing habitats,
             3.   change in the community structure  or abundance
                 of existing  biotic  assemblages,
             4.   changes in process  rates of individual  popu-
                 lations or of integrated biotic  communities.
     The overall  objectives of studies  to evaluate  the effects  of
cooling water use include demonstration of the  ecological  changes
induced by a small  temperature increase in a limited area  of the
receiving waters.  If changes are found through comparative stud-
ies, ultimately  causes must be ascribed to those  changes through
comprehensive laboratory experiment  on  individuals  and populations.
Such experiments, in and of themselves, are not sufficient  dem-
onstration of acceptability unless  they relate  findings  back to
the field.  In order to support the  criterion of  adequacy,  investi-
gators  should demonstrate that they have-performed  studies both
before and after  the construction and  operation of  a licensed
faci1ity whi ch:
             1.   have determined biological populations  occurring
                 in the body  of water  under consideration,
             2.   have determined abundance of populations,
             3.   present meaningful  indices of  the  structures  of
                 biological communities, '
             4.   have obtained valid estimates  of basic  process  rates
                 associated with biological communities  present,
                                67

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             5.  have extended over a time interval sufficient
                 to detect and quantify both existing trends
                 and cyclic natural variations within the system,
             6.  have been coordinated with physical and chemical
                 studies such that a comprehensive description of
                 the environmental mil ieu has been presented.
     In the last analysis, the most convincing demonstration of
the adequacy of studies is repetition and confirmation by indepen-
dent experts.  It is therefore strongly recommended that corrobora^
tive studies be sponsored by agencies responsible for the pro-
tection of the public interest.
Re!iabi1i ty
     1.  Accuracy:  The accuracy of tests, measurements, or pro-
         cedures should be supported by known standard samples
         and evaluation by independent methods.   Estimates of the
         magnitudes of inaccuracies should be clearly defined and
         included in data reports.
     2.  Precision:  Tests, measurements and procedures should be
         replicated to provide clear estimates of uncertainties
         in precision, and those estimates should be included in
         all reports.
     3.  Acceptable levels of uncertainty:  The  investigator
         should routinely provide estimates of uncertainties
         which may exist in all aspects of his work.
     4.  Independent review and verification of  evidence by
         recognized experts should be encouraged.
                                  68

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Accountabi 1 ity
     1.  Where techniques permit, voucher specimens  should be
         permanently preserved in a recognized repository for
         possible taxonomic or qualitative verification.
     2.  Copies of original data on destructive analysis  (chem-
         ical  and biochemical  measurements) and measurements of
         transient phenomona (physical  and meteorological)  should
         become part of the public record.  "Original  data" is
         construed to mean the first digital  output in standard
         measures.
     3.  For analyses using both qualitative  identification and
         enumeration (analysis of biological  assemblages),  orig-
         inal  data (as defined above) should  become part  of the
         public record and should be permanently preserved  in a
         recognized repository.
     4.  For all  determinations requiring interpretation  or expert
         opinion, all authors  of interpretations and opinions should
         be  clearly identified and qualified.
     5.  Independent review and verification  of supporting  evidence
         by  recognized experts should be encouraged.

                 Introduction  to Priority Needs
     The term priority research is inappropriate to the purpose
of this section of the Report  which would seem to be more to
recommend corrective measures  to improve the  usefulness of
current and  future data, than  to propose further development of a
methodology  or of data.  Priority numbers assigned therefore re-
flect the relative values of those steps which, in the best judg-
                             69

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ment of the Panel, would tend to push forward the goal  of data
improvement with greatest possible speed.  Priority values have
been ranked according to the following scheme:
                 1 - highest priority consistent with achieving
                     primary goals of the Panel,
                 2 - high priority studies supporting priority 1
                     items,
                 3 - intermediate priority but ultimately providing
                     support to both 1 and 2.
     Since tried and acceptable techniques exist for these
analyses, categorization based on current status of the data is
unnecessary.
                           PRIORITY NEEDS

1.  To standardize units of measurement for each parameter for
    which environmental data are collected, by agreement between
    Lake Michigan investigators and institutions.
    Priority 1
2.  a.  To develop uniform specifications for environmental data
        which render them appropriate for computer storage.
    b.  To investigate the feasibility of, and to adopt where
        feasible, standardized data forms which would facilitate
        transfer and computer storage.
    c.  To adopt standardized coding for environmental  data which
        would permit computer storage.
                                70

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    d.   To arrange for a central  data bank to contain, analyze and
        distribute raw and analyzed data on thermal  problems and
        their associated effects.
        Priority  1
3,   To  negotiate  for,  and to  designate specific public libraries
    as  repositories for all  reports to assure the availability
    of  Information on  Lake Michigan thermal  problems.
    Priority 1
4.   To  determine  the levels  of statistical significance necessary
    for routine analysis of  the various types of environmental
    data (acceptable levels  depend on the depth of knowledge of
    the sub-discipline or organism-group, the frequency and number
    of  species  and the base  of experience in testing the effects of
    environmental  perturbation on  the population and community
    structure).
    Priority 2
5.   To  recommend  revision, production and uniform acceptance by
    Lake Michigan  investigators and institutions of  biological keys
    which are inadequate or  which  do not now exist.
    Priority 3
6.   To  determine  from  available data the within-sample variation
    which might be expected  from  biological, chemical  and physi-
    cal parameters of  interest in  determining the effects of the
    introduction  of waste heat into Lake" Mi chigan.
    Priority 2
                                  71

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 7.   To estimate, based on data on within-sample variability,  the
     numbers of replicate data necessary to detect various  magni-
     tudes of difference between groups of data.
     Priority 2
 8.   To specify descriptive statistics and accompanying  confidence
     limits to be reported for each type of environmental  data col-
     lected.
     Priority 1
 9.   To specify measures of biotic diversity (if any)  which are
     appropriate for each biological  parameter.
     P r i o r i ty 1
10.   To specify the analytic procedure or procedures  to  be  used
     to assess each type of spatial or temporal  environmental
     difference.  If alternative analyses are available, the
     criteria through which a choice  may best be made  should be
     clearly stated.
     P r i o r i ty 1
                                 72

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                   Literature Cited
Cairns, J.,  Jr.  and  R.L.  Kaesler.  1969.   Cluster analysis
     of Potomac  River survey stations  based on protozoan
     presence-absence data.   Hydrobiologia 34:414-432.

       \
Cairns, J0,  Jr.  and  R.L.  Kaesler.  1971.   Cluster analysis
     of fish in  a  portion of the upper Potomac River.
     Trans.  Amer.  Fisheries  Co.  100:750-756,,
Cairns,  J.,  Jr.,  R.L.  Kaesler,  and R.  Patrick.  1970.
     Occurrence  and  distribution  of diatoms  and other algae
     in  the  upper Potomac  River.   Not.  Natur.  Acad.  Natur.
     Sci.  Philadelphia.  No.  436.  12 pp.
Cochran, W.G.  and  G.N.  Cox.  1957.   Experimental  Designs.
     Wiley,  New York.   617 pp.
Dorris,  T.C.  and J.L.  Wilhm.  1968.   Biological  parameters
     for water quality criteria.   BioScience 18:477-480.
Grieg-Smith,  P.  1954.   Quantitative Plant Ecology.
     Plenum Press,  London.   256 pp.
Guenther,  W0C0  1964.   Analysis  of Variance.   Prentice-Hall,
     Englewood  Cliffs, N0J.   199 pp.
Horn,  H.S.  1966.   Measurement  of "overlap"  in  comparative
     ecological  studies.   Amer.  Natur.   100:419-424.
Kaesler,  R.L.  and J.  Cairns,  Jr.  1972.   Cluster analysis
     of data  from limnological  surveys  of the  upper
     Potomac  River.   Amer.  Midland Natur.  88:56-67,,
                        73

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Kaesler, R.L., J. Cairns, Jr. and J.M. Bates.  1971.
     Cluster analysis of non-insect macro-invertebrates
     of the upper Potomac River.
     Hydrobiologia 37:173-181.
Lloyd, M., J.H. Zar, and J.R. Karr.  1968.   On the
     calcuation of information-theoretical  measures of
     diversity.  Amer. Midland Natur.  79:257-272.
Pielou, B.C. 1966.  The measurement of diversity in
     different types of biological  collections.
     J0 Theoret. Biol. 13:131-144.
Roback, S.S., J. Cairns, Jr., and R.L.  Kaesler.  1969.
     Cluster analysis of occurrence and distribution of
     insect species in a portion of the Potomac  River.
     Hydrobiologia 34:484-502.
Scheffe, H. 1959.  The Analysis of Variance.
     Wiley, New York.  477 pp.
Sneath, P.M.A. and P.K. Sokal.  1973.   Principles  of
     Numerical Taxonomy.
     W.H. Freeman, San Francisco.   573 pp.
Snedecor, G.W. and W.G. Cochran.  1967.   Statistical
     Methods.  Iowa State University Press,
     Ames, Iowa.   593 pp.
Sokal, R.R. and F.J. Rohlf, 1969.   Biometry.
     W.H. Freeman, San Francisco.   776  pp.
Steel, R.G.D. and J.H. Torrie.  1960.   Principles  and
     Procedures of Statistics.
     McGraw-Hill, New York.   481  pp.
                         74

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Whittaker, R.H.  1967.   Gradient analysis of vegetation.
     Biol  Rev.  49:207-264.
Zar, J.H. 1974.   Biostatistical  Analysis.   Prentice-Hall,
     Inc.  Englewood Cliffs,  N.J.   620 pp.
                        75

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            SECTION III



MEASUREMENT OF THE EFFECTS OF COOLING



  WATER USE ON PHYSICAL PARAMETERS

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Section III.  MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
              PHYSICAL PARAMETERS

                      TABLE OF CONTENTS
Definition of Physical Parameters 	  80
Objectives of Measurement of Physical Parameters  ...  81
Questions Answerable  Through Physical Measurement ...  81
     Natural Physical Conditions  	  81
     Predictive Information   	  82
     Monitoring Discharge Plumes  	  83
     Distribution of  Chemicals Added  to the Discharge.    .  83
Physical Sampling Sites   	  83
     Intake	83
     Discharge	84
     Littoral Area	84
     Profundal Area	85
Iterative Sampling Changes	86
Physical Parameters of Interest   	  86
     Water Temperature	86
     Lake Currents    .....    	  87
     Turbulent Diffusion  	  89
     Wave Height and  Wave Length	90
     Turbidity	90
     Light Intensity  in  the Water	91 •
     Related Meteorological Variables  	  91
     Other Physical Measurements  	  92
                                78

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      Determination of Ambient  Temperature  	    93
Physical  Data and Ecological  Effects    	    94
Introduction to Priority Research  	    96
Priority Research	     .     ....    97
                                     79

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Section III.   MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
                      PHYSICAL PARAMETERS

               Definition of Physical Parameters
      The physical parameters considered significant to this
program are variables which may be changed from their natural
values by the use of lake water for once-through cooling, and
related meteorological variables which affect mass movement of
the lake water and heat exchange between the lake and the atmo-
sphere .
     The direct effect of a condenser cooling water discharge is
to change the values of some physical variables such as tempera-
ture, gas solubility, etc., in a relatively small area of the
lake.  The biological effects of the discharge itself (as
differentiated from intake or condenser passage effects which
are considered in a separate section of this report) are indirect
effects resulting from the physical changes.  In order to
determine both the immediate and persistent biological effects of
the discharge it is necessary first to determine the area in which
measurable physical perturbations occur.  These man-made physical
changes should be related to the averages and extremes of the
natural physical variables in the lake.  Designation of the
physical measurements to be made depends upon the study objectives.
                                   80

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        Objectives of Measurement of Physical Parameters

1.   To describe the distribution  through  time  and  space,  parti-
    cularly in the littoral  area,  of those  physical  variables
    influencing water quality  and  the  biota of the lake;
2.   to provide adequate  physical  data  to  improve  prediction of
    variations in physical  aspects  of  the water mass  caused by
    discharge plumes;
3.   to verify thermal plume  models  which  aid in describing the
    variability of plume behavior  in the  lake;
4.   to collect data for  monitoring  the  physical effects  of
    condenser water discharges.

       Questions  Answerable Through Physical Measurement
Natural  Physical  Conditions
1.   To what extent is the water  of  the  sublittoral and  littoral
    area  and water inshore of  a  thermal bar restricted  in inter-
    change with the remainder  of  the lake?
2.   What  is the rate  of  dispersion  of  pollutants  away from the
    shoreline and what physical  parameters  influence  this rate?
3.   What  is the relative importance  of  the  wind and  of  density
    differences induced  by solar  heating  in driving  the  circu-
    lation of the lake?
4.   Can  the heat added by condenser  water discharges  significantly
    increase the volume  of water  in  the epilimnion in the summer
    and/or significantly affect  the  vertical  distribution- of''.
                                     * .
    temperature and dissolved  material?
                              81

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5.   How frequent, extensive, and persistent are upwellings  and
    what role do they play in bringing nutrient laden waters
    into the euphotic zone?
6.   What is the normal, and what are the extremes of, light
    penetration in the lake?
7.   What is the normal, and what are the extremes of, winter
    temperature distribution in the lake?
8.   To what depths are sediments disturbed by wind induced  mixing
    of the lake in different seasons of the year?
9.   What, if any, is the influence of ice on shore erosion?
Predictive Information

1.   From what strata of the lake is the intake water withdrawn?
2.   For what periods of time and to what extremes and average
    temperatures are aquatic organisms exposed when they meet
    elevated temperatures in discharge plumes?
3.   What is the extent and temperature range of a sinking plume?
4.   What is the velocity field around the intake?
5.   To what extent can a discharge plume be confined to the shore-
    line by lake motion?
6.   What are the appropriate methods for predicting the size  and
    location of a discharge plume under natural conditions  of
    lake variability?
7.   Where and how should discharge and intake structures be lo-
    cated and designed to minimize important biological effects?
8.   What influence does bottom configuration have upon the  dis-
    persion of thermal discharges?
                               82

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Monitoring Discharge Plumes
1.  Can discharges significantly influence turbidity and light
    penetration?
2.  To what extent do discharges erode and transport bottom
    sediments?
3.  To what extent might a discharge plume prevent or destroy
    the formation of ice and result in additional  shore
    erosion?
Distribution of Chemicals Added to the Discharge
1.  How do physical forces act upon additives to the discharge and
    what is the distribution of additives in the discharge itself?
                    Physical Sampling Sites
    The following sections identify those locations where physical
parameters should be measured to answer questions  related to
physical and biological effects of use of the lake for cooling
water.  Details of how the measurements and frequency relate to
the study objectives are discussed in a later section.  Meteorologi-
cal variables apply to all locations; however, they can usually be
grouped as relating either to inshore or offshore  conditions.

Intake
    Temperature and water currents are important physical parameters
in the area of the intake.  Preoperational studies can determine
ambient water temperatures and, if recirculation from the discharge
does not occur, help in prediction of intake temperatures during
                             83

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operation.  During plant operation, intake temperatures can be
monitored routinely in the plant.  Preoperational current studies
at the intake can be used to identify the permanent effects of
currents caused by plant operation.  Measurements for verifica-
tion may be made during plant operation.
Discharge
  Temperature and currents should also be studied at the dis-
charge.  Discharge water temperature can be monitored in the
plant.  Current and turbidity measurements can be made from the
point of discharge into the lake to  points beyond the expected
zone of influence.  Pre-operational studies of ambient conditions
near the discharge will determine physical characteristics of the
receiving waters before plant operation.  During operation these
data may be used for comparison with reference areas outside the
zone of plant influence.
  During plant operation, physical variables are measured to de-
fine (1) temperature distribution of the thermal plume, (2)
currents in the plume as compared to ambient conditions, (3) mean
and maximum residence times of entrained organisms, (4) relative
mixing and dispersion of the discharge water into ambient lake
waters, and (5) changes in turbidity resulting from the other
identified changes.
Littoral Area
  All cooling water withdrawal and discharge occurs in what would
be classified as the littoral areas.  Extensive measurements of
physical parameters at numerous littoral sites are required for
an adequate categorization of uses currently made in the nearshore
water of Lake Michigan.
                              84

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These comparative measurements  are useful  in evaluating alterna-
tive locations for new cooling  water uses  as for evaluating the
differences in physical  effects of existing uses.   The Physical
Subcommittee offers a tentative selection  of five  areas based on:
     1.  Similarities in the nature of shoreline,  bottom material
         and depth contours.
     2.  Similar biological  characteristics.
     3.  Distribution of power  stations and other  sites at which
         data are regularly  collected.

         AREAS INCLUDED:
         a.  Kewaunee-Point  Beach
         b.  Waukegan-Zion
         c.  Michigan City-South Haven
         d.  Ludington
         e.  Northern Rocky  Shoreline
Profundal Area
     Measurement of physical variables in  the profundal area is
much more difficult than in  the intake, discharge  or littoral
areas.  Consequently, sampling  programs for measurements at offshore
locations require justification.  The only questions linking the
characteristics of offshore  waters with cooling water in a physical
sense relate to the rate of  interchange between the offshore and
inshore waters.  Special programs (involving temperature, current
or dispersion measurements)  should address this question.  A
sampling program designed for long-term or routine monitoring of
physical variables of profundal areas does not seem germane.
                             85

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                  Iterative Sampling Changes
     The physical sampling program will necessarily change as
biological problems are identified.  For instance, if it is
determined that the far field region, where temperatures are less
than 2C (3F) above ambient, is biologically unimportant, physical
measurements of the energy exchange coefficient at the surface of
the lake becomes relatively unimportant.  If this far field
region is unimportant, ambient lake turbulence is also relatively
unimportant for predicting plume behavior.

                Physical Parameters of Interest
     The physical variables of interest for study of cooling water
effects on Lake Michigan include water temperatures, lake currents
ambient turbulence defining dispersion (eddy diffusivities,
entrainment coefficients), turbidity, light penetration, surface
heat exchange coefficients, and meteorological variables such as
wind speed and direction, air temperature,  relative humidity, and
incident and reflected radiation.

Water Temperature
     Temperature is the most significant physical variable to
these studies because it determines the buoyancy field and relates
directly to the physiological responses of the biological organisms
Fortunately, it is also one of the easiest variables to measure.
Using water temperature, or its increase, as a conservative label
it is possible to trace cooling water passing through the plant.
Unfortunately, temperature is not a unique tag or tracer and at
times temperature increases due to added heat can become confused
                              86

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with natural  temperature variation.   Using temperature as a tag
often leads to problems in defining  the plume due to local
differences in ambient water temperatures.
     The temporal and  spatial  characteristics of ambient water
temperatures in Lake Michigan are not well known.  Data are needed
on the temporal and spatial variations of ambient water temperature
at specific sites, to compare operational biological data with
natural conditions.  Specifically, data are needed to define and
describe (1) spatial and temporal variations in surface temperature,
and  (2) temperature variations  with  time and depth, providing
information on upwellings, natural stratification, thermal bar
phenomena, sinking plumes, and  possible recirculation of plume
water into intakes.  Preferred  units of expression are degrees
Celsius (degrees Fahrenheit).  Water temperature measurements for
most studies should be made to  the nearest 0.1C (0.2F).  When
the  change in heat content is to be  calculated over a short time
period, a precision of 0.01C (0.02F) may be required.
Lake Currents
     A number of parameters are associated with the dispersive
mechanisms that act upon the cooling water plume.  Some of these
are  actual physical variables (currents) and some are mathematically
defined parameters (eddy diffus1vities) depending upon the parti-
cular mathematical formulation  used  to describe the situation.
     Lake current is the primary mechanism transporting heat into
the  lake from the point of discharge.  Currents affect the tra-
jectory of the plume, and the intensity of turbulence.  Very
                               87

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little is known about the speed, direction and persistence of
near-shore currents (within 10 km).  Data of this type are not
only essential for thermal  plume predictions, but also 1n under-
standing erosion problems in the lake.   To describe and interpret
near-shore currents, information is also needed on wave heights
and periods, offshore currents, wind speed and direction, atmos-
spherlc stability, 1n addition to data  on near-shore currents
themselves.
     There are two types of currents directly associated with the
thermal plume Instrumental  1n dispersing heated water:  those in-
duced by the initial momentum of the discharge and those induced
by density differences (buoyant spreading).
     One of these effects usually dominates, depending upon the
location of that point where momentum dissipates and buoyant
forces become dominant.  Currents induced by momentum effects are
relatively well understood for simple configurations, but more
data are needed for an understanding of boundary effects such as
those caused by the bottom and the interactions with ambient lake
currents; specifically, how are forces  exerted on the plume by the
ambient current and the bottom?  Currents produced by buoyant
forces are less well understood and no  mathematical models avail-
able for predicting plume behavior in large lakes specifically
include this phenomenon, even though it is Important in producing
the sharp Interface observed on the upcurrent side of the plume.
Data are especially needed on the temperatures and currents at
this interface.
     The flow of the water is a function of current speed and direc-
tion.  Preferred units of expression are cm/sec (ft/sec) for cur-
rent speed, and degrees of the compass  for direction.  The
                               88

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precision needed for current speed is embodied in a current meter
with a threshold of 3 cm/sec (0.1  ft/sec) and an accuracy of 10
percent; and +_ 5 degrees in direction.
     If current measurements are to be  made in areas where the
orbital wave velocities affect the currents, a current meter must
be chosen that is insensitive to orbital  motion.  (Current meters
with Savonious rotors as sensing elements are not recommended.)
     Properly designed drogues and suitable position location
techniques are an acceptable and inexpensive method of obtaining
current data.  The cross sectional area of a drogue exposed to
underwater drag should be at least 100  times the area above water
that is exposed to wind forces.
Turbulent Diffusion
    Turbulent diffusion is  an hydrodynamic process  related to flow
and turbulence which describes the distribution of  suspended ma-
terial, solutes, and heated waste  as  by measuring velocities,
temperatures, and/or tracer concentrations and fitting mathematical
models to the data.  Values are  therefore dependent upon the model.
It is not feasible to specify precision for measurement of diffu-
sion because there is no clearly defined  reference  value.   Turbulent
eddies, the mechanism by which energy is  provided to produce mixing,
occur over a wide spectrum  of eddy sizes.  Thus, measurements of
turbulent dispersion (eddy  diffusivities) must include eddies that
are at least as large as the largest  dimension of the plume.  Values
of turbulent diffusion coefficients are usually several orders of
magnitude greater in the horizontal than  in the vertical direction,
particularly under stratified conditions.  Dye dispersion  is a
                               89

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technique used to measure diffusion, however, erroneous results
may be produced where buoyant forces are significant.
Wave Height and Wave Length
   Height, frequency and directional characteristics of surface
waves determine their effects on water motion at various depths
and their effect on turbidity and sediment movement.  A number of
waj/es are always present at any location or time so that repre-
sentative wave height, wave length, and period would normally be
obtained from a time-varying record.  Suitable measurements might
be obtained visually or may require a lengthy and accurate time
series record for power spectrum analysis.  Additional  approaches
may use wave prediction techniques through meteorological  data
and airborne sensors.
   Wave heightmeasurements should be expressed in meters (feet).
Calculated values for wave length and direction should  be  ex-
pressed in meters (feet) and degrees of the compass (true), re-
spectively.  Desired precision of wave height measurement  depends
on the purpose,  though an accuracy of 10 cm or 2 percent  of full
scale is readily attainable.
Turbidi ty
   Turbidity may be determined roughly from Secchi disc depths or
more precisely from photometric attenuation. Turbidity  is  a biolog-
ically important parameter that can have a profound effect on
primary productivity.  Turbidity can also be a measure  of  turbulent
mixing for it is this turbulent energy that lifts the sediments
from the bottom and holds them in suspension.  Turbidity can also
be used as a tracer to identify various water  masses.   Measure-
ments would be.limited to the relatively shallow water  areas.
                              \
                             90

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Light Intensity In the Water
     The objective of the measurement of light intensity is usually
the measurement of the depth of the euphotic zone, the principal
zone of energy conversion by green plants.   In this context pre-
cise depth measurements are more important  than precise light in-
tensity measurements.  The instrument preferred for light intensity
measurements in the water is a submarine photometer.  Photometer
readings at various depths in the lake can  be converted to extinc-
tion coefficients and related to turbidi ty readings made on water
samples in the laboratory.  Photometric techniques lend themselves
to spectral analysis, should this be required.  Secchi disc
readings are difficult to relate to measurements made with other
instruments or to models of primary production and are therefore
of limited value.
Related Meteorological Variables
     Thermal energy introduced into the lake is eventually given
up to the atmosphere and to outer space.  Various mass and energy
exchange phenomena that take place at the air-water interface are
important in the rates of exchange.  Analyses of existing plumes
indicate that most of this energy is lost from the plume regions
that are less than 2C (3F) above ambient.  If the peripheral region
of the plume, where the temperature differential is less than
2C (3F) above ambient, is important from a  biological point of
view, then measurements of the factors influencing surfacing heat
exchange must be made»  These factors include gradients in the air
temperature, velocity and humidity above the water surface, water
                           91

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temperature, solar and atmospheric radiation and reflected and
emitted radiation from the surface of the water.
     Meteorological measurements are needed as mentioned above, to
evaluate surface energy exchange rates, and these measurements are
desirable to correlate near-shore surface conditions to parameters
more easily measured than near-shore currents.  These measurements
are readily made with existing equipment and techniques.  The
major difficulty that may occur is in obtaining suitable towers or
sites for measurement over the water.  Related meteorological
variables are those influencing temperature, flow, turbulence,
dispersion rates, exchange of heat between the lake and the
atmosphere, and local water turbidity.  The following variables
may be measured, though not necessarily at each site.
1.  Air temperature in C (F), +_ 1C (2F).
2.  Lake surface water temperature (for determination of
    atmospheric stability) should be measured with a precision
    of +_  1C  (2F).
3.  Relative humidity in percent, +_ 5 percent.
4.  Wind speed in km per hour (miles per hour), +_ 3.0 km per hour
    (+_ 2.0 miles per hour).
5.  Wind direction in degrees (true) of the compass, to +_ 10
    degrees.
6.  Net radiation balance in langleys per day (Btu/ft2/hr), + 10
    langleys per day (+_ 1 Btu/ft2/hr.).
Other Physical  Measurements
     Two specific phenomena,  occurring in Lake Michigan  and  important
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to thermal  plume dispersion,  are development of a thermal  bar during
spring (and sometimes in early winter)  and possible occurrence of
sinking plumes.   Both occur when water  above 4C mixes  with water
below 4C.   Observations  of both phenomena  are made primarily by
temperature measurement.  Development of a thermal bar is  a dynamic
process and, in  general, is easily measured by instrumentation
located on  a boat or be  infrared overflights.  Sinking plume data
can be obtained  through  fixed sensors on the lake bottom or measure-
ments taken from a boat; both methods have advantages  and  disadvan-
tages.  Unfortunately weather sometimes prevents research  vessels
from obtaining sinking plume  data during cooler months when the
sinking condition is most likely to exist.
Determination of Ambient Temperature
     Water  Quality Standards  for temperature proposed  for  Lake
Michigan by the  U.S. EPA and  adopted at least in part  by all four
states (Illinois, Indiana, Michigan, Wisconsin) are based  upon
an allowable mixing zone of approximately  72 acres in  area for
those waters with temperature greater than 3F above the "natural"
temperature or less than a specified maximum temperature for the
month.  "Natural" is defined  as the temperature that would exist
in the absence of artificial  heat inputs.  • At present  there is
not clear definition of  how "natural" temperature is to be
determined.
     "Ambient" temperature, the temperature that would exist in
                                         ,1
the absence of heat input, must first be determined.  Attempts to
define ambient temperature have created considerable difficulty
in the reduction and interpretation of  field data acquired over
                           93

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the last four years.  For instance, natural surface temperature
measurements have shown changes greater than 1C (2F) over a
distance of 180 meters (600 feet) in a direction parallel to the
beach.  Moving in a direction perpendicular to the shoreline, data
have shown differences as much as  3C (5-1/2F)  in distances of
600 meters (2000 ft.).  This was a case of shoreline heating where
temperature decreased moving away from shore; a completely natural
process.  With upwelling conditions, which occur rather frequently,
differences of as much as  4C (7F)  in 910 meters (3000 ft.) have
been observed.  Under these conditions ambient temperatures also
vary with time.  Data have shown that the ambient surface tempera-
ture increases as much as  3C (5-1/2F)  over a 2 hour period during
a calm day with a large solar energy input.  This layer of warm
water was less than 1 ft. deep.
     This questions the point in time and space at which a tempera-
ture to be called "ambient" can be identified.  Both cooling water
users and regulatory agencies need a clear definition of the method
of identifying the ambient temperature.   Should a method be considered
that uses measurements at greater depths than the upper few microns,
infrared scanning cannot be used as a monitoring tool.
              Physical Data and Ecological Effects
     Collection of physical information is intended to  assess the
ecological effects of the use of Lake Michigan for cooling. Con-
tributions fall into two main, interrelated categories, which
provide:  (1) a description of the influence of natural variables
operating on physical characteristics of the lake, over both long
and short time scales (e.g,, both seasonal and episodic during
                                94

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storms or upwelling,  and  on the  life  history,  growth,  and mortality
of lake organisms  which  live or  migrate within the  influence of
cooling water);  and,  (2)  a  description  of the  intensity,  extent,
and direction of the  mechanical  and thermal  perturbations imposed
on living organisms  by the  cooling  water in  its  passage through the
intake, pumps,  and condensers and  continuing during its dispersion
from the outfall.
     It follows  that  an  adequate description of  category  (2),  this
panel's ultimate objective, is not  possible  without substantial
knowledge of the natural  variation  under category (1).   It also
follows that the program  of physical  measurement must  be  designed
using the best  information  biologists can provide on the  life
histories, distribution,  movement,  and  thermal and  mechanical
tolerances of those  groups  of organisms which  either represent
a direct resource  (e.g.,  fish and  fish  food),  or which  contribute
in a more subtle way  to  a healthy  ecological situation  in the
lake.
     The scale  of  time,  distance and  the frequencies over which
tolerances and  physical  variables  are measured must match the
scales and frequencies of exposure  of the organisms to  the
perturbation in  question.  However, these scales and frequencies  may
differ among organisms;  for example,  planktonic  organisms making
a single passage through  the plant  and  plume differ from  organisms
entrained only  in  the outer plume,  or from sessile  groups only
occasionally or  remotely  influenced by  a plume.   However, it seems
that the assessment  of ecological  effect on  these
                                95

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relatively local scales is a prerequisite for any reliable assess-
ment of lakewide effects.
                Introduction to Priority Research
     The following research is identified in the body of the
discussion on physical parameters which are considered necessary
to adequately assess environmental changes resulting from the
introduction of waste heat into Lake Michigan.  These questions
have been selected as possible keys to a more rapid accomplishment
of research, resulting in a better understanding of lake
conditions.  Assigned priorities represent the judgement of the
Panel as to the relative importance of these key topics balanced
against the availability of data.  The need for physical measure-
ment by other subcommittees committed to assessment of the
aquatic environment through chemistry or through the biota have
been used to adjust these priorities.  Priority values may be
ranked according to the following scheme:
     1 - highest priority consistent with achieving primary
         goals of the Panel,
     2 - high priority studies supporting priority 1 items,
     3 - intermediate priority, but ultimately providing support
         to priori ty  1 ,
     4 - low priority, supporting other programs but not of
         critical importance in itself,
     5 - deferred priority of a general supporting nature.
     These research topics have also been placed in categories
                              96

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which reflect the current status of the data, and the assigned
values may be interpreted in the following way:
     1 - as soon as possible using available data,
     2 - using data currently being collected,
     3 - by means of individual  research projects not now under-
         way.                                N-
                        Priority Research

A.  Toward Assessment of Natural Physical  Conditions
    1.  To determine the extent  to which the littoral and sub-
        littoral area, or water  inshore of a thermal bar is
        restricted in interchange with the remainder of the Lake.
        Priority 2, Category 3
    2.  To determine the rate of dispersion of pollutants away from
        the shoreline, and physical parameters which influence
        this rate.
        Priority 2, Category 3
    3.  To determine the relative importance of the wind and of
        density differences induced by solar heating in driving
        the circulation of the Lake.
        Priority 2, Category 3
    4.  To determine the effects of water exchange on epilimnetic
        volume and/or vertical distributions.
        Priority 5, Category 1
    5.  To determine the frequency, extent and persistence of
        upwellings and the role  they play in bringing nutrient
        laden waters into the euphotic zone.
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        Priority  2,  Category  2
    6.   To  determine the  normal  and  the  extremes of  light
        penetration  into  the  waters  of the Lake.
        Priority  3,  Category  3
    7.   To  determine the  normal,  and  the  extremes of, winter
        temperature  distribution  in  the  Lake.
        Priority  5,  Category  1
    8.   To  determine to what  depths  sediments are disturbed by
        wind-induced mixing of  the Lake  in different seasons of
        the year.
    9.   To  determine what,  if any, is the influence  of ice on
        shore  erosion.
        Priority  4,  Category  2

B.   Toward Development of Predictive Information

    1.   To determine from what  strata of the Lake  intake water
        is withdrawn.
        Priority 5, Category  2
    2.   To determine the periods of  time and extremes  and average
        temperatures to which aquatic organisms are  exposed  when
        they meet elevated temperatures  in  discharge plumes.
        Priority 1, Category  2
    3.   To determine the extent and  temperature range  of a sinking
        plume.
        Priority 1, Category  2
    4.   To determine th.e velocity field  aroirnd  an  intake.
        Priority 1, Category  3
                               98

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    5.  To  determine the extent to which a discharge  plume  can  be
       confined  to the shoreline by  lake motion.
       Priority  3, Category 1
    6.  To  determine appropriate methods for  predicting  the size
       and location of a discharge plume under  natural  conditions
       of  lake variability, and the  influence of  bottom configura-
       tion on thermal dispersion.
       Priority  2, Category 2
    7.  To  determine where  and  how  discharge  and intake  structures
       should  be located and  designed  to minimize important bio-
        logical effects.
        Priority  1, Category 3

C.   Toward  Monitoring  Discharge Plumes

    1.   To  determine  the  extent to  which  discharges erode and
        transport bottom  sediments.
        Priority  3, Category 2
    2.   To  determine  the  extent to  which  a  discharge plume might
        prevent or destroy  the  formation  of  ice  and result in
        additional  shore  erosion.
        Priority  4, Category 1
D.   Toward  a Determination  of  the  Distribution of  Chemicals

    1.   To  determine  the  action of  physical  forces upon  additives
        to  the  discharge  and distribution of  additives in the
        discharge itself.
        Priority  2, Category 3

                               99

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                 SECTION IV



MEASUREMENT OF THE EFFECTS OF COOLING WATER



         USE ON CHEMICAL PARAMETERS

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Section IV.   MEASUREMENT  OF THE EFFECTS OF COOLING WATER USE  ON CHEMICAL
                                PARAMETERS

                           TABLE OF CONTENTS

Introduction 	    103
Definitions  Of Chemical Parameters   	    104
      General  Water Quality   .   .   .  • .   .	104
      Additions From Plant Operation 	    104
      Air  Pollutants	104
      Precision and Units of  Expression  	    104
Objectives of The Measurement of Chemical Parameters  	    110
Questions Answerable Through  Chemical Measurements   	    110
Chemical  Sampling Sites   	    Ill
Method of Sampling       	112
Frequency of Sampling    	    113
      Site Evaluation Studies	113
      Monitoring	114
      Operational Monitoring	114
      Replication of Samples	115
Changes in Operational Monitoring Program    	    116
Chemical  Data and Ecological  Effects 	    116
Priority Research	    .    .    117
                                  102

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 Section IV.  MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
                     CHEMICAL PARAMETERS
                          Introduction
    The chemical  parameters  considered in this section are those
used in definition of water  quality.   In many instances, chemical
analyses are considered a part of or  a supplement to biological
studies; these analyses might be more appropriately considered
an integral  part  of the biological  studies.   This section is
concerned with those studies needed to determine the changes in
water quality which might result from cooling water use.
    There are several  committees addressing  problems in  the  water
quality of Lake Michigan.  These include the Laboratory  Directors
of the Calumet Area-Lake Michigan Conference, the Monitoring
Committee and Toxic Substances Committee of  the Lake Michigan
Enforcement Conference, the  Environmental Quality Committee  of
of the Great Lakes Commission, and  the Upper. Lakes Reference Group
and the Great Lakes Water Quality Board of the International Joint
Commission.   The  Lake Michigan Cooling Water Panel is concerned
with the effects  of cooling  water use on water*quailty and on its
effects on the biota.   It is anticipated that lines of communi-
cation will  be established with these other  committees,  so that
information on chemical parameters  can be easily exchanged.
                              103

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                  Definitions of Chemical Parameters

     Cooling  water use  may  produce  changes  in water quality by
 changing  the solubility  of dissolved  gases, by changing the rate
 of biological  processes  which  produce water quality changes, and by
 the  addition of  materials  used in  plant operation.  In coal fired
 power  plants,  drainage or  leachate  from fly ash holding ponds may
 reach  the  cooling water  discharge.  In a plant where cooling
 towers  are used,  the evaporation of water  causes  increases in
 the  concentrations  of  substances already in the cooling water.
 Chemicals  used for  slime and corrosion control and air pollutants
 scrubbed  from  the atmosphere may also be discharged.
 General Water  Quality
   The  parameters  used to  describe water quality  in general are
 listed  in Table  IV  - 1.
 Additions from Plant Operation
   Representative  substances which might be used  in plant operation
 are  listed in  Table IV - 2.
 Air  Pollutants
   Representative  substances which might be scrubbed from the atmo-
 sphere  and appear  in cooling tower blowdown are listed in Table IV-3
 Precision and  Units of Expression
   The  preferred  units of  expression for chemical  parameters  are
 metric, usually milligrams  per liter (mg/1) for chemical  substances
 dissolved or suspended in  the water.  Occasionally micrograms per
 liter  is the appropriate unit of expression.  The units of expres-
 sion used in reporting for  the results of  chemical analyses should
conform to those  of the USEPA STORET System.
                                104

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Table IV-1.  Water quality parameters to be considered In site
             selection studies and monitoring studies
Wastewater Components
Bacteria, Fecal  Coliform*
Biochemical  Oxygen Demand*
Chemical  Oxygen  Demand
Cyanide
Hexane Soluble Materials

Nitrogen, Organic*
Phenols
Total  Organic Carbon
Plant Nutrients

Nitrogen, Ammonia*
Nitrogen, Nitrate*
Nitrogen, Nitrite*
Phosphorus, Soluble*

Phosphorus, Total*
Silica*
Water Supply Parameters
  Alkalinity*
  Color
  Chloride
  Fluoride
  Hardness
  Iron
  Manganese
  Oxygen, Dissolved*
  pH*
  Solids, Total Dissolved*
  Solids, Total Suspended

  Sulfate
  Turbidity
  Potentially Toxic Materials
  (examples)
  Arsenic
  Boron
  Chromium
  Lead
  Mercury
  PCBs
Nickel
Selenium
Si 1ver
Zinc
Pesticides
Phthalates
* Parameters which should be a.part of all water quality evaluation;
  other parameters are suggested for consideration when there  is
  reason to believe that they may be present in unusual concentrations
                                105

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Table IV- 2.  Chemicals used in plant operation.
Name
Use
Form to be Monitored
Al urn
Chlorine
Lime

Phosphates
Sodium Carbonate
Sodium Hydroxide
Sodium Sulfite
Sulfuric Acid
Boric Acid
Hy d r a z i n e
Morpholine
Phosphates
Chromates

Phosphates
Organic Phosphates
Zinc
Chlorine
Silt control, poly-
mers
    acrylamide
    polyacrylate
Water Treatment
Water Treatment
Water Treatment

Water Treatment
Water Treatment
Water Treatment
Water Treatment
Water Treatment
Reactor
Reactor
Reactor
Reactor
Cooling Tower

Cooling Tower
Cooling Tower
Cooling Tower
Cooling Tower
Cooling Tower
Al ion
Free and combined chlorine
Ca ion, hardness, alka-
linity, pH
Total and orthophosphate
Na ion, alkalinity, pH
Na ion, pH
Na ion, oxygen
S04 ion, pH
Boron
Ammonia - N
Ammonia - N
Total and orthophosphate
Trivalent and Hexavalent
Chromi urn
Total and orthophosphate
Total and orthophosphate
Zinc ion
Free and combined chlorine
                    Ammon.ia - N
                    Organic - f!
                    BOD •
                                106

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Table IV -  2.   Chemicals used in plant operation.
                            (continued)
 Name
Use
Form to be Monitored
     polyethyleneamine
 Dispersants          Cooling Tower
     sodium  lignosul-
     fonate
 Organic  biocides     Cooling Tower
     sodium  polychl-
     orophenol
     quaternary amines
     methylene bis-thi -
     ocyanate
     etc.
 Oxygen  inhibitors    Cooling Tower
     sodium  mercapto-
     benzothiozole
     benzotriazole
                    etc.
                    BOD
                    Phenols

                    Organic - N
                    Ammonia - N

                    etc.

                    BOD

                    Organic sulfides
                                107

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Table IV - 3.  Some atmospheric contaminants which may appear in
               cooling tower recirculating water.
               Iron
               Lead
               Copper
               Nickel
               Vanadi urn
               Zinc
Phosphorous
Chromi urn
Cadmi urn
Mercury
Arseni c
Ammonia
Sulfite
                            108

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     The precision and accuracy required for each individual
determination depends  upon  the objective of the measurement,
the natural  variation  in ambient concentration, and the availa-
bility of analytical  techniques and instruments with appropriate
precision.   The laboratory  responsible for the analysis should be
prepared to  demonstrate that the sample collection, sample
handling, and laboratory methods are adequate to provide the
required precision and accuracy for the parameter.   As a part of
this demonstration,  Standard Samples prepared in EPA laboratories,
should be analyzed.   Samples should occasionally be replicated to
demonstrate  that the methods give reproducible results.  Other
uncommitted  laboratories should analyze aliquots of the same
sample.
     The regulations,  40 CFR, Part 130, TEST PROCEDURES FOR THE
ANALYSIS OF  POLLUTANTS, of  the Federal EPA should be followed in
making the chemical  analyses except when greater sensitivity than
provided by  those techniques is required by the objectives of the
analyses.  In those  instances where alternative analytical
techniques are required, approval should be requested through the
Regional Director of EPA Region V or the State Pollution Control
Agency.
                               109

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     Objectives  of The Measurement of Chemical Parameters
To monitor cooling water to determine:
   a.  if the cooling water use produces changes  in water quality or,
   b.  if there are changes in water quality from other sources
       which might produce biological  changes.
      Questions  Answerable Through Chemical Measurements
1.  Does cooling water use result in dissolved  gas super-saturation
    to the extent that it is  a threat  to organisms in  the discharge
    piume?
2.  Does cooling water use result in loss of significant amounts
    of dissolved oxygen from  the discharge plume?
3.  Does cooling water use result in increase  in  Biochemical  Oxygen
    Demand in the discharge plume?
4.  Does cooling water use result in an  increase  in total quantities
    of algal nutrients or an  increased  availability of algal  nutri-
    ents?
5.  What chemical substances  are present in the drainage or leachate
    from a fly ash holding pond?
6.  What chemical substances  are present in the blowdown from a
    cooling tower which is introduced  into the  discharge?
7.  Does cooling water use increase taste and  odor problems in the
    lake water?
                              «
8.  Are  there substances present in the  water  whose rate of
    uptake, accumulation and  toxicity  might be  changed by a temper-
    ature change?
9.  Are  power plants  a source of toxic,  persistent organic compounds?
                               110

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                     Chemical  Sampling  Sites

NOTE:   Whenever possible,  stations  should be  located at sites pre-
       viously occupied or logically selected to maximize continu-
       ity of data.

1.   Measurements of  chemical  water  quality should be made at in-
    take and discharge to  determine changes in water quality
    occurring in the plant and long-term water quality trends of
    the lake water.
2.   Point sources  (including  tributary  contributions)  of waste-
    water discharge  in the area of  the  power  plant (within 5 miles)
    should be monitored to determine effects  on the local aquatic
    comnium' ties.
3.   Water quality  should be monitored in the  discharge plume to
    determine the  concentration gradients of  materials discharged
    and to determine possible biological effects of the discharge
    on water quali ty.
4.   Special  studies  of chemical water quality should be conducted
    at shallow and deep water stations  to define quality differences
    between  these  two  areas.
5.   Special  studies  of water  quality should be conducted at refer-
    ence stations  near and at some  distance from power plants to
    determine long terms trends of  water quality in Lake Michigan.
6.   Special  studies  should be undertaken to answer questions raised
    under item 3.
                               Ill

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                        Method  of Sampling

    A wide spectrum of sampling methods is required for water
quality analyses as a part of the  studies of cooling water use.
Continuous recording instruments and composite samplers are needed
for monitoring intake and discharge while a Kemmerer or Van Dorn
sampler may be appropriate for lake samples.  Careful  attention
should be given to containers used  in transporting samples and
appropriate methods for preserving  and handling samples so that
alteration or contamination is minimized.
    It is not feasible to specify  methods and special  considera-
tions for sample handling and preservation required for each of
the possible water quality analyses.  The laboratory responsible
for the results should demonstrate  that the methods provide the
precision and accuracy required by  the objectives.
                                112

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                      Frequency of Sampling

     Sampling frequency depends on the type and the objectives of
the study and availability of background data.  The types of studies
considered here are site evaluation studies, plant monitoring studies,
and special studies.
Site Evaluation Studies
     Site evaluation studies should provide data to aid in selection
among alternative sites and determination of problems particular to
a specific site.  Water quality factors are usually less critical
to site evaluation than are physical  or biological factors.
    Water quality surveys  similar  to  sanitary  surveys should be
considered part cf site evaluation studies:   sources  of waste
water within five miles of the  proposed site should be located and
characterized,  rivers  discharging  to  the lake  within  the area
should be evaluated, surface runoff within  five miles of the pro-
posed site should be surveyed,  and specific sources of waste
materials in the runoff (animal  raising operations, fertilized
agricultural fields, highways which contribute oils and'salt, etc.)
should be identified.
    Use of water in the area of the proposed site  should also be
identified; withdrawals for either domestic or industrial  water
supply, and the extent of  recreational  water use in the area of
particular interest.
    Water quality samples  should be collected  from the area of
proposed intake and discharge and  analyzed  for the parameters
listed in Table 2.  Preferably  these  samples should be collected
                              113

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and analyzed once each season for at least one year.  Where there
are severe time limitations, at least one set of samples should
be collected and analyzed.
     Unusual findings obtained during the site evaluation survey
should be related to specific inputs of materials.
Monitoring
     This program shoald be a continuation of the site evaluation
study and should provide a basis for evaluating the results of opera-
tional  monitoring.  The location of sampling sites depends on plant
design  and the expected operational  monitoring program.
Operational Monitoring
     This program should include parameters measured continuously,
weekly, seasonally, and semiannually.  Measurements should be made
in the  intake and discharge to determine the direct effect of plant
operation on water quality and on areas unaffected by the discharge
plume to provide data on the rate of dispersion of chemicals dis-
charged and to identify other inputs in the area.

1.   Continuously
     The following should be monitored continuously in the plant
     intake and discharge:  temperature, dissolved oxygen, specific
     conductivity, and turbidity.   In addition, if chlorine is used
     for disinfection in any part of the plant operation, the dis-
     charge should be sampled for total residual  chlorine at the
     time of introduction.
                               114

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2.   Weekly
    The following  should  be  measured  weekly  in  the  intake  and
    discharge:   alkalinity,  ammonia  nitrogen,  fecal  coliform,
    biochemical  oxygen  demand,  chloride,  color,  hardness,  nitrate,
    nitrite,  organic  nitrogen,  orthophosphate,  pH,  total  dissolved
    solids,  total  suspended  solids,  and  sulfate.
3.   Seasonally
    The following  chemicals  should  be measured  in  the  intake,
    discharge,  and the  discharge  plume once  per  season:
    aluminum,  arsenic,  boron,  cyanide, chloride,  hexane-soluble
    materials,  magnesium,  phenols,  sodium, and  strontium.
4.   Semi annually
    The following  should  be  measured  in  the  intake  and discharge
    on a  semiannual  basis:   barium,  beryllium,  cadmium,  chromium,
    copper,  lead,  mercury, molybdenum, selenium,  silver,  stronti-
    um, tin,  vanadium,  and zinc.
 Replication of  Samples
      Replication  of samples  and analyses should be built into these
 programs  to define the range of variability.  A minimum of two
 replicates should be taken at each sampling.  Additional replicates
 may be required for those parameters which show high  variability
 in the intake water and for which detection  of small  changes in con-
 centration may  be of significance to the measurement  of biological
 effects.
                              115

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            Changes In Operational Monitoring Program

Changes in the sampling programs could be considered when:
1.  the concentration of a given chemical parameter does not
    change significantly over a one year period, or
2.  the concentration of a parameter is in a range in which the
    cooling water use would have no effect, or
3.  the range of variability is so great that detection of
    changes in the value of the parameter is excessively difficult, or
4.  there is a process change in the plant which would alter the
    characteristics of the discharge.
               Chemical  Data and Ecological  Effects
    Chemical water quality data are of value primarily for
determining mechanisms of ecological  changes.   For example,  a
sudden decrease in photosynthetic rate in the  area of the dis-
charge might be due to excessive temperature,  mechanical  damage
during condenser passage, toxic chemicals, or  a combination  of
all three.  If such an effect is measured, then its cause  should
be determined.  An investigation would include chemical  analyses
of the samples in which the effect was noticed.
    The relationship of chemical data to ecological  effects  de-
pends first upon measurement of the ecological effect and then
the use of chemical analyses to determine the  cause.   Thus,  it
is not possible to.specify a_ priori what chemical  analyses are
needed.  Hypotheses describing the mechanisms  by which changes in
                               116

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chemical  water quality could  cause the observed ecological  effect
must be formulated and tested using appropriate chemical  procedures
However,  well  known changes  in chemical  water quality can cause
large ecological  effects  for  example:   a depletion of hypolimnetic
oxygen for several weeks  completely changes  the benthic communi-
ty, or an increase in the concentration  of soluble orthophosphate
from levels below the limiting concentration greatly increases the
likelihood of  nuisance algal  blooms.   Monitoring water quality
changes due to cooling water  use should  detect types of water
quality changes which cause  these predictable ecological  changes.
                          Priority  Research

    Research priorities identified here  are  questions which were
developed while describing studies to  increase understanding of
the effects of thermal introduction on water chemistry.  The
selection itself, and the assigned priority  values were determined
by a demonstrated need for answers in  these  areas and because
other, perhaps more far-reaching research, depends upon the
results of these studies.  In addition,  the  available data, or the
relative  ease  with which  data may be obtained, has been used as
a factor  for selection and for categorization.  Adjustments have
been made in priorities and  categories originally assigned  by the
subcommittee based on best judgment and  needs of the entire Panel.
Priority  values have been ranked according to the following scheme:
    1 - highest priority  consistent with achieving primary  goals
        of the Panel ,

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                             f
    2 - high  priority studies supporting priority 1 items,
    3 - intermediate priority but ultimately providing support to
        priority  1 ,
    4 - low priority supporting other programs but not of critical
        importance in itself,
    5 - deferred  priority of a general supporting nature.
Since this subcommittee chose to arrange these studies by category,
categorical criteria are self-explanatory.

Category 1.   Answers to these questions should be developed as soon
as possible using available data.

1.   To determine dissolved  oxygen at the  intake and  discharge  of
    representative Lake  Michigan  power plants  and the  extent to
    which  cooling water  use results  in the loss of dissolved
    oxygen from the discharge plume.
    Priority  1
2.   To determine the extent to  which cooling water use results in
    an increase in biochemical  oxygen demand.
    Priority  1
Category 2.  Answers to  these questions  should  be developed  using
data currently being collected.
1.   To determine if cooling water use results  in an  increase in
    total  quantities of  algal nutrients  or in  an increased availa-
    bility of algal nutrients.
    Priority  1
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2.  To determine chemical  substances present in the drainage or
    leachate from fly ash  holding ponds at representative Lake
    Michigan power plants.
    Priority 3

Category 3.   Answers to these questions should be developed by
means of individual  research projects  not now underway.
1.  To determine chemical  substances in cooling tower blowdown.
    Priority 2
2.  To determine if  cooling water use  results in dissolved gas
    supersaturation  to the  extent that it is destructive of
    aquatic  life.
    Priority 2

 3.   To  determine  substances  present in  the  water whose  toxicity
     is  significantly  altered  by  a  temperature  change.
     Priority  4
 4.   To  determine  the  toxicity of chemicals  used  in  plant
     operation or  in  cooling  tower  operation.
     Priority  1
 5.   To  determine  if  increased temperature results  in  a  significant
     increase  in  the  rate of  uptake  of materials  injurious  to  fish.
     Priority  3
 6.   To  determine  the  rate  of  oxygen demand  by  benthic organic
     deposits  in  Lake  Michigan and  the effect  of  increased  tempera-
     ture  on that  rate.
     Priority  4
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                     SECTION V



MEASUREMENT OF THE EFFECTS OF COOLING WATER USE  ON



   PRIMARY PRODUCER AND CONSUMER COMMUNITIES

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Section V.  MEASUREMENT OF THE EFFECTS OF COOLING WATER USE  ON
             PRIMARY PRODUCER AND CONSUMER COMMUNITIES

                        Table of Contents

Introduction 	  123
Principal Problems   	  123
Objectives of the Measurement of Microbiota  ....  126
Measurement of Environmental Provinces   	  127
Phytoplankton	128
     Introduction	128
     Questions to be Answered	132
     Approaches	135
        Field Observations	135
        Measurements	137
        Evaluation	139

Zooplankton .        	141
        Introduction 	  141
        Field Studies:   Questions    	  148
        Field Studies:   Implementation   	  149
        Laboratory Studies:  Questions   	  155
Microbenthos	157
        Introduction 	  157
        Approaches   .	    .   .  158
Particulate Fallout  	   .....  159
Benthic Respiration  .     .	'.   .  160
Priority Research    	  161
Literature Cited  ....  -	163
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Section V.  MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
          PRIMARY PRODUCER AND CONSUMER COMMUNITIES
                          Introduction
     It should be recognized at the outset that a good deal more
quantity and quality of information is necessary to assess the
effects of thermal  effluents on communities of microscopic organisms
in Lake Michigan than that which is presently available.  Insuf-
ficient attention has generally been given to some or all of these
communities in available studies on thermal effects.  In many cases,
it is necessary to  pose questions which have not yet been asked of
the Lake Michigan system to provide a basis for management deci-
sions.   Some of the problems particular to microbiological com-
munities are discussed briefly below.
                       Principal problems
     Perhaps the most fundamental problems with microbiological
communities is their extreme complexity.  Hundreds of species may
be found in a single sample from certain primary producer com-
munities in Lake Michigan and many more may be expected to fall
within  the thermal  effect of any single facility.
     Unfortunately, the composition of such communities is poorly
known at even the fundamental level of identification.  Taxonomic
                                i
treatises which comprehensively Itreat many of the important groups
are unavailable.  Even basic historic works are scattered and scarce
Detailed investigations of thermal effects at the community level
will  frequently require development of a taxonomic base during the
study.   In addition, there is a paucity of investigators with
training and background necessary to approach these problems in
Lake  Michigan.  Perhaps because of this lack of fundamental
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knowledge, there are potentially important types of communities
for which practically no information exists.   This is true of all
indigenous bacterial communities and of most benthic primary
producer communities, particularly those occurring in deeper
parts of the Lake.
     Another characteristic of microbiological  communities which
impeded an understanding of their responses is  the variation in
abundance and composition in a single season, at any given sampling
station (Vol1enweider et al., 1974).  Any microhabitat may be
occupied by several associations during a season.  Natural seasonal
succession is responsible for a large part of this variation but
it is strongly suggested that succession is increased by environ-
mental disturbance.  This means that to detect  natural patterns
of change, more replicate samples of microorganisms should be
collected per unit time than for larger organisms, especially in
disturbed areas such as the nearshore zone of Lake Michigan.  It
is also true that the grand growth  period for  many associations
occurs during the late autumn and early spring when field operations
are most difficult on Lake Michigan.
     Many microbiological communities in Lake Michigan contain repre-
sentatives of fundamentally different biochemical divisions:  This
causes serious problems in sampling and preservation for population
              ii
studies (Uterir.ohl , 1958) and equally serious  problems in designing
and implementing quantitative experimental studies.  In many in-
stances, it is necessary to preserve and/or  analyze multiple.  •
aliquots using different methods to insure that all important group's
                               124

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are adequately treated.
     Rapid turnover and  specific responses of the microbiota to
heat also causes difficulty in the study of thermal  addition on
microbiological  communities.   Doubling times of the  species,
where known, range from  hours  to days and significant population
changes may be effected  by short exposure to a stress.   (Goldman and
Carpenter, 1974).   In the Great Lakes, the change may be extirpation
of native populations and/or  introduction of'exotics (Stoermer and
Y2ng, 1959; Hchn,  1959).   Unlike  higher organ i 317,3,  the dispersal
of most primary producer  species  is  relatively  rapid (Rosowski  and
Parker, 1971).   It appears,  for example, that the phytoplankton flora
of Lake Michigan is presently changing quite rapidly (Stoermer,1972).
It also appears that benthic primary producer communities have
changed drastically in the past 100  years, although this situation
is not as well  documented as changes in the phytoplankton.
     The rapid  response time of microbiological  communities hinges
on the fact that most communities are self-regulating to at least
some degree either through biochemical antagonisms  or by sequester-
ing nutrients (Schelske and  Stoermer, 1972; Fogg,  1965).   Exposures
to increased temperatures have been  known  to select for  populations
which pre-empt  space, nutrients or both and which become widespread
in the system through those  mechanisms (Foerster  etal., 1974).   Cer-
tain species of blue-green algae  which are both  favored  by  relatively
high temperatures  (Cairns, 1972)  and known to excrete antagonistic
fractions, may  constitute a  serious  potential nuisance in Lake   -
Michigan.
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     Unlike higher organisms, these organisms have little or no
avoidance capacity.  Effects of multiple passage or relatively
long thermal exposure in plumes can be expected to be more severe
in the microbiological communities than with organisms with suf-
ficient mobility to escape.   It is basically understood that in
the trophic dynamics of an aquatic ecosystem, measurable effects
on the primary producers are manifested throughout the system.
Changes in the abundance or composition of carbon reserves fixed
at low trophic levels are important in the growth and mainten-
ance of fishes and other higher forms (Benson and Lee, 1975).   It
is also apparent that changes in microbiological communities may
have direct effects on human welfare in Lake Michigan.  Since
primary uses of the Lake include requirements for high quality
potable water and utilization of the Lake and its shore zone for
recreation, biological over-productivity or changes in the qual-
ity of the communities are of immediate and substantial public
interest  (Vaughn, 1961).

         Objectives of the Measurement of Microbiota

Operationally, studies should proceed in several distinct phases:
1.   The first should be a background study providing an assessment
     of spatial and temporal distribution, and baseline numbers
     in populations occurring in the region of the proposed facil-
     ity, and existing trends in such populations.  Although some
     of this information may be available from the literature,
     exploratory field studies are strongly recommended-:
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2.    Based on the above,  detailed  study of the waters in the im-
     mediate region of the  proposed facility can then be designed.
     The output from the  latter study should provide a detailed chart
     of the populations  occurring  or passing through  the region
     of probable measurable  thermal  effect,  and the  seasonal vari-
     ations in such populations.   Reference  stations should be in-
     cluded for comparison  with stations  in  the regions of imme-
     diate effect, and  fnr nnc^ihlp He term i na t i nn nf  1 a |c o uiirjo effects.
     This study should be initiated well  in  advance  of initial con-
     struction when possible  and should extend through at least five
     years of the full  operation of the facility.

3.    If changes in population abundance,  community  structure, or
     process rates are detected, experimental studies should be de-
     signed and initiated to  isolate and  quantify  any causes which
     can be ascribed to  cooling water use,  directly  or indirectly.
              Measurement of Environmental  Provinces

 Studies should recognize and treat with  biological  provinces with-
 in  Lake Michigan:
 A.    The nearshore zone  (ca.   8 miles  from  shore)
      1.  Milwaukee -  Michigan  City
      2.  Michigan City  - Little Sable  Point
      3.  Little Sable Point  -  Pyramid  Point
      4.  Pyramid Point  - Mackinac
      5.  Grand Traverse  Bay
      6.  Northern Islands  areas
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     7.  Mackinac - Point Detour
     8.  Bay de Noc and Green Bay north of Chambers Island
     9.  Southern Green Bay
    10.  Deaths Door - Algoma
    11  .  Algoma - MiIwaukee
         a.  The vicinity of any major stream or other effluent of
             any of the above regions.
         b.  The open water zone
             1.  South of  42° 30'N
             2.  42°  30'N - 44° 30' N
             3.  Grand Traverse Bay
             4.  North of 44°  30'  N
             5.  Bay de Noc and Green Bay north of Chambers Island
             6.  Southern Green Bay

These geographic regions do not precisely delineate habitat types;
however, communities in these regions are sufficiently different
that caution is necessary in making a direct comparison of results
appropriate for another.  In addition, it is suggested that there
is a consistent difference in plankton assemblages in the eastern
vs. western  portions of the open water zone and the effects of cool-
ing water use must be determined as it pertains to those assemblages
in a further attempt to measure lakewide effects.
                          Phytoplankton
Introduction
     Phytoplankton are microscopic  plants -which are suspended in water
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In large lakes, such as Lake Michigan, most of the species which
comprise the phytoplankton complete their entire cycle free floating;
others exist on solid substrates.   Such communities are quite complex.
At least ten major divisions of the Plant Kingdom are represented
in phytoplankton communities of Lake Michigan.  Because of fundamental
differences in morphology, life histories, and physiological  require-
ments in representatives of these   divisions, few generalizations
can be made at the community level.  Even generalities regarding the
representatives of any one of the  major divisions are apt to  be mis-
leading.  Individual species belonging to some of the major divisions
have been reported from almost every conceivable aquatic situation.
Something on the order of 2000 individual   species are now known to
occur in the Lake and undoubtedly  others will be reported in  the
future.
     The majority of these organisms are either passive, or so feebly
motile that they cannot overcome water movements even when  velocities
are low.  Some respond actively to physical and chemical stimuli in
the environment but their  capacity for avoidance is essentially nil.
     Phytoplankton organisms known to occur in Lake Michigan  range
in size from 1.0 micrometer in greatest dimension to something over
500 micrometers.  The great majority are functionally unicellular,
although colonial aggregations are common in most of the divisions
represented.
     Both the abundance and composition of phytoplankton communities in
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Lake Michigan, particularly in the nearshore waters, is highly vari-
able.  Depending on location and season, numbers may range from
200 cells/ml to over 30,000 cells/ml (Stoermer,1972).   Composition
in different localities ranges from domination by species usually
considered to be indicative of very  high water quality, to domina-
tion by species which are abundant in highly eutrophied waters in
the Great Lakes system (Stoermer and Yang 1970).
     Perhaps the most outstanding characteristic  of primary producer
communities in general, and the phytoplankton in particular, is
their rapid and total response to environmental  change.  Most
phytoplankters have generation times ranging from several hours to
several days so that perturbations of the system may cause rapid
reactions.  Most of these microorganisms are cosmopolitan in dis-
tribution and when conditions are significantly changed indigenous
or existing species associations may be rapidly replaced by other
organisms.  Changes of this type have occurred in Lake Michigan
and elements of the present phytoplankton community  probably were
not present in the Lake before the intervention of man (Stoermer and
Yang, 1969).
     The principal role of phytoplankton in the aquatic ecosystem
is primary production.  In a sense, these organisms operate at the
interface between the physical and chemical milieu and organisms
at higher trophic levels, since they utilize radiant energy to fix
essential chemical elements into metabolically useful  substances.
In large lakes, such as Lake Michigan, the habitat-aval Table, to
phytoplankton far exceeds that available to'other primary producer
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communities requiring solid substrates for their growth, and energy
fixed by phytoplankton is the primary controlling factor in total
productivity of the ecosystem.   A fact often  overlooked is that
while the abundance and physiological condition of phytoplankton
controls the amount of material  available to higher levels  in the
food chain, the kinds of phytoplankton also determines the type of
material available.  If changing environmental  conditions result in
a change in phytoplankton composition from dominance by one division
to dominance by another with  greatly different biochemical charac-
teristics, serious impact may be observed in the consumer communities.
It should be observed that such  changes occur with increasing intro-
ductions of domestic and industrial  waste. Because  characteristics
of the drainage basin of Lake Michigan and its  considerable thermal
inertia, indigenous phytoplankton populations still existing in the
Lake were adapted to conditions  of low nutrients and low temperature.
The primary factor controlling  productivity was the availability of
phosphorus.  The characteristic  seasonal  cycle  of phytoplankton
abundance has consisted of a spring  and autumn  maximum and rather
uniformly low populations during the rest of the year. (Stoermer and
Kopezynski, 1967).  The indigenous flora  was dominated by diatoms
(Bacillariophyta)  and microflagel1ates belonging to several divisions
(Chrysophyta, Pyrrophyta, Cryptophyta) with relatively small numbers
representing other divisions (Cyanophyta, Chlorophyta) which are
usually important in smaller lakes in the regions(Ahlstrom, 1936).
Most of these  organisms are perennial and appear to be cold steno-
thermal although  experimental  evidence regarding temperature require-
ments of species native to Lake  Michigan  is almost entirely lacking.
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 It is suspected that their requirements for low temperatures  were
 met during the summer months by a vertical  adjustment to the  area
 of the  thermoclineal 1 owed by the high transparency of the offshore
 waters  of Lake Michigan.
       At present, phytoplankton communities in the Lake are under-
 going substantial change.  Changes in the ecosystem, apparently
 human induced, have caused replacement of the indigenous flora of
 the inshore waters by introduced species particularly during  the
 spring  period of maximum productivity (Stoermer,  1972). Productivity
 levels  have been substantially increased and there is growing evi-
 dence that phosphorus is no longer the limiting element (Schelske
 and Stoermer, 1972).  Depletion of available silica is of particular
 concern during the summer stagnation when it is reduced to  levels
 which will not support diatom growth.  Since species belonging to
 other divisions which do not require silica for growth, particularly
 the Cyanophyta, and Chlorophyta,  are favored under such conditions,
 it is believed that nuisance  conditions caused by the proliferation
 of green and blue green algae may arise in  Lake Michigan as they have
 in Lake Erie and Lake Ontario.  Most nuisance species of blue-green
 algae (Cyanophyta) apparently require relatively  high temperatures,
 so that addition of heat to nearshore waters may  contribute to such
 undesirable conditions.
 Questions to be Answered
       The following general questions should be addressed both in
the context of the system as it is now (pre-operational), and  after
the addition of heated effluents and other facts associated with
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operations of a facility with a thermal  discharge.
1.  What populations are present?
    a.  What are the seasonal differences in occurrence and
        abundance?
    b.  What are the spatial  differences in the region of the
        facil ity?
    Comment;
    Clearly it will  be necessary to develop information regarding
                                                     .   .  ...
                                                     ui  u I u i u ^ I *~ a I
response such as species diversity ordination analyses.   Specific
identifications may pose considerable difficulties for reasons al-
luded to earlier,  however taxa encountered should be identified
to the species level.
2.  What is the characteristic population structure of such
    assemblages?
    a.  Are there  characteristic seasonal changes?
    b.  Are there  regional  differences?
    Comment;
    It is suggested that comparative measures of .assembl age com-
position and  abundance,  such  as  ordination analysis or similar
techniques, be employed.  Simpler indications of assemblage struc-
ture, such as the  various diversity indices,  are notoriously dif-
ficult to interpret for  phytopl ankton.
3.  What are  the measurable process rates associated with such
    assemblages and how  are they affected by  thermal additions
    and other factors  connected  with cooling  water use?
                             133

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     a.  Growth rates of abundant populations.
     b.  Productivity rates.
     c.  Nitrogen fixation rate.  (Vanderhoef et al., 1972).
     d.  Uptake of key nutrient elements.
         1.  Phosphorus
         2.  S i 1 i c a
         3.  Nitrogen
     Interpretation of the answers to these questions may be
difficult since the historic data base for the phytoplankton is
weak and certain informational  links between species and numbers
are lacking except on a local and recent basis.   To close these
gaps, it is important that answers to the following questions be
developed by water users as a group, for use in  individual  site
investigations:
1.   What was the composition of the plankton populations which
     were present in earlier years?  Phytoplankton communities in
     most areas of Lake Michigan are already severely perturbed
     and the indigenous fauna and flora, in the  strict application
     of the term, no longer exist.  Efforts should be made to re-
     construct the original composition through  review of literature,
     preserved collections, or by paleolimnologic methods.   This
     historical perspective is necessary to establish the background
     of acute and chronic change which has occurred in the Lake's
     flora and fauna through time, caused by human influence.  This
     background would permit comparisons  with current data by pro-
     viding a standard against which to measure  more recent effects.
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      In addition, a better understanding of the changes which have
      transpired in plankton populations may permit prediction of
      future trends and guard against permanent exclusion of the
      indigenous fauna and flora by thermal  pollution.
2.     What are the ranges of spatial  and seasonal  variation within
      such a system?  Since, in phytoplankton ,  extreme variations
      in total assemblage abundance and equally  significant changes
      in community structure may occur in lateral  distances of a few
      cooling water requires  extremely sensitive measurement and analy-
      sis methods.   Program designs should demonstrate this capability
      and explicitly  state limits of detection of modifications which
      occur.
3.    What are the  trends and causes of trends of phytoplankton
      abundance and species composition now present within the system?
      Since thermal effects are largely synergistic, it is important
      to demonstrate  that additional  thermal  loading will  not  in-
      tensify problems  resulting  primarily from other types of pertur-
      bation  (Beeton  and Barker,  1974).  If information is inadequate,
      studies should  be focused on explanation of these trends.
Approaches
         Field Observations
          An  extremely  comprehensive program of field sampling is
      necessary to  answer the questions posed.  Some principal aspects,
      including sampling location and frequency, should be determined
                                                   ' o.      ' .
      through knowledge of the discharge characteristics of the plant
      (e.g.,  shoreline, submerged jet, length of canal or. conduit,
                               135

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velocities, etc.) and the regional characteristics of the
lake environment (e.g., water quality, location of signifi-
cant pollution introduction, location  of spawning or nursery
grounds, etc.).  Fixed stations will be necessary for develop-
ment of comparative data and it is believed that, for initial
determination, the sampling area should be equal to an area
encompassed by twice the radial distance from the cooling
water discharge to the most extreme  1C  isotherm.  Since the
position of this isotherm is extremely variable, and perhaps
undefinable, the suggested distance is arbitrary and is certain-
ly subject to enlargement or diminution depending upon sound
evidence.  In any event, sampling intensity should concentrate
in the vicinity of the discharge on the assumption of greatest
effect.  It should be incumbent on the plant operator to demon-
strate valid estimates of microbiota (abundance and species
composition) to the 95 percent confidence level for the area
sampled in order to detect the extreme of possible effects  of
cooling water use.   In view of variation found in the micro-
biota through space and through time, the exact number of stations
cannot be specified but initial arrays of 64 stations may be
justi fied.
    Accompanying physical and chemical data should parallel
logical sampling.  Again,  in view of variability previously
found in the microbiota through time (Holland and Beeton, 1972)
monthly sampling frequency is a minimum effort.  Weekly or  bi-
weekly samples are desirable during periods of expected seasonal
pulses.
                           136

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    Measurements
    Measurements which should be made on  samples  include:
1.   Estimates on standing crop biomass should be  made  from all
    samples.   Method of choice is assay of extracted chlorophylls
    (Strickland and Parsons,  1968).   Results  should be validated
    by independent methods such as assay  of total  organic  carbon
    or total  organic nitrogen.
2.   Estimates of rate of primary productivity should be made from
    all  surface samples and from all  depths at not less than ten
    stations  strategically located with respect to depth and dis-
    tance from thermal source.  Method of choice  is measurement of
    14C  uptake rate (Strickland and Parsons,  1968).
3.   Estimates of nitrogen fixation should be  obtained  from all
    surface samples.  Method  of choice is acetylene reduction
    technique (Stewart et al., 1967).
4.   Estimates of species composition  and  abundance of  phytoplankton
    assemblages should be obtained from all samples by microscopic
    identification and enumeration of organisms in suitable prepared
    whole water samples.  Because of  diversity of biochemical groups
    present,  care should be taken to  employ techniques of  identification
    suitable  for particular groups to insure  accuracy.  These measure-
    ments should be made in a temporal sequence which  permits
    calculation of growth rates for predominant populations.
5.   Estimates of concentration of both particulate and dissolved
    major nutrients (Phosphorus, Nitrogen and Silica)  should be
                                                                *
    made on all samples.
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     In addition to sampling in the vicinity of the facility,  at
least one array of stations, consisting of a line transect at  dis-
tances of 1/8, 1/4, 1/2, 1, 2, 4, 8, and 16 statute miles from
shore should be established within the same biological  province
as the primary grid, but as far removed as possible from human
effects.  These stations should serve as a reference for near-site
studies and as a monitor of possible whole lake effects.  These
stations should be sampled in the same manner, and at the same
intervals as the primary grid stations and this same suite of
analyses should be performed.
     After discharge, a much larger volume of water is  heated  by
the mixing and dilution of the plume with surrounding water than
the volume of water which actually passes through the plant.   Al-
though the temperature elevation is not as great as in  the plant,
the small increase may have a great effect on the microbial community.
Whereas large temperature increases in the plant may result in
mortality, inhibition of various metabolic processes or, a short-term
stimulation of metabolism, lower temperature elevation  in the  mixing
area may cause a prolonged stimulation of metabolic activity,  growth
and reproduction.
     In addition to a program to measure metabolic rates in the field,
experimental studies should be included.  Measurement of the  rate
of carbon fixation by a series of ^C experiments on samples  incubated
at temperatures artificially elevated above -ambient conditions is
appropriate.  Experimental temperatures bracketing those existing or
               c
predicted for a given power plant will reproduce the seasonal  response
of phytoplankton to increased temperature.  This information  may then
                 v            138

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be evaluated for Isothermal  areas  to  predict overall  response of
phytoplankton to thermal  elevation.
     Evaluation

Experimental procedures should evaluate the following:

      1.     Effects  of temperature elevation o,n carbon  uptake.   Rates
            should  be  measured at  small  temperature  increments  above
            ambient,  conditions up  to  and exceeding  maximum temperature
            observed or expected for  the power plant.   For example,
            if the  particular  power  plant has  an  expected  cooling  water
            temperature rise of IOC   and the ambient  lake  temperature
            is 8C,   samples  collected from an  area  not  influenced  by
            the plant  should be incubated at 8,  10,   12,   14,  16,  18,
            and 20C.

      2.     The effect of  exposure to elevated temperatures  through
            time.
      Samples from  reference areas should be exposed  to similar tem-
 peratures  for similar lengths of  time.   After exposure, samples should
 be  returned to ambient temperature and  the rate  of carbon uptake  de-
 termined  to assess  the effects of exposure to elevated temperatures
 through  time.
      Metabolic processes  such as  respiration, nitrogen fixation and
 uptake  of  other nutrients could also be observed  in  a  similar  manner
 to  assess  thermal  effects.
      These  studies  could  be extremely valuable for providing design
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engineers with some of the numbers necessary to design more ecologi-
cally compatible systems.  By knowing temperature response of the
plankton, appropriate condenser temperatures can be selected.  In-
formation on temperature response of the plankton and the effects
of exposure to elevated  temperatures through time could aid  in
designing discharge structures to minimize harmful effects.
    Development of predictive models of the metabolic response of
phytoplankton or other microbial groups to elevated temperatures would
be an extremely valuable aid in design, or assessing the effects of
operating plants.  Such  models could not be applied to all areas of
the Lake due to differences in species composition, nutrient condi-
tions, and other factors, but might provide estimates of impact on
the microbial metabolism.  Modelling would also reduce repetitions
of experiments at proposed power plant sites.
    Another experiment which should be considered is observation of
natural phytoplankton cultures following exposure to elevated tem-
peratures.  Large cultures held at elevated temperatures or eleva-
ted for short periods of time and returned to ambient should be
observed through time for changes in species composition and abun-
dance.  These observations could provide clues to the effects of
thermal elevation on the composition of the phytoplankton community
at a particular site or  in the Lake as a whole.
    Each of the experimental procedures outlined above should be
conducted at least six times per year during all  seasons of the year
for at least three years.  After evaluation of the results, it may
be possible to discontinue the work.
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                          Zooplankton

Introduction
     Zooplankton  are  animals  characteristically  spending  a  sig-
nificant part of  their  life-cycles  suspended  in  water.  Most
prominent or  quantitatively  significant  species  in  the  zooplank-
ton of typical  continental  fresh  waters  are  holoplanktonic,  that
is, no life stage is  spent outside  the  plankton.   Marine  zooplank-
ton by contrast includes  a significant  number of meroplanktonic
forms, where  suspended  egg or larval  stages  later give  rise  to
sedentary ones.  In  typical  fresh water, including  Lake Michigan,
this link between planktonic  and  benthic communities  is tenuous,
although there  are exceptions of  possible importance.   There  is
also a blurring of the  distinction  between planktonic  and seden-
tary or benthic organisms  in  some inshore waters, since there are
organisms which more  characteristically  attach to bottom  materials
or surfaces of  rooted higher  plants  and  which briefly  enter  the
plankton when migrating vertically  (there are examples  among  the
Cladocera, Ostracoda, Mysidacea,  Amphipoda,  and  Insecta).  The
same phenomenon occurs  in  waters  adjacent to  the bottom at  dis-
tances from the shore.   It is one factor distinguishing inshore
and offshore  zooplankton  assemblages.
     Exceptions of possible  importance  in Lake Michigan are  the
fol1 owing:
1.  Numerous  species  of insects occurring in  a large  lake spend
only the egg  and  pre-adult periods  there, leaving it  as adults
(e.g. many Diptera,  Trichoptera,  Plecoptera).  Some are planktonic
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for short but well-defined stages (Diptera:   Tendipedidae,  some
species during very early and very late larval, and entire  pupal
stages; Culicidae, Chaeoborus, during entire larval and pupal
stages).
2.   Most of the species in some of the major zooplanktonic groups
(Cladocera, Rotifera, Copepoda; see below) have an  encysted, dia-
pausal stage (e.g. the mictic egg in Cladocera and  Rotifera)
which is highly resistant to damage from mechanical injury, desic-
cation, or unfavorable chemical conditions,  and which can leave
the water to be distributed as a dust particle by the wind  or other
agent.  This characteristic gives a species-population the  means
to avoid unfavorable conditions, and may also explain the nearly
cosmopolitan distributions of many planktonic forms.
3.   Certain macrozoobenthic species, in Lake Michigan most strikingly
Pontoporeia affinis and Mysis relicta, regularly migrate vertically
through a sufficient distance to carry them well beyond the benthic
biotope and into the zooplankton, at least at certain seasons or
certain time of day.
     The bulk of the Lake Michigan zooplankton, as  of most  inland
waters of reasonably large size, is composed primarily of individuals
of four major animal groups, the Cladocera and Copepoda (Arthropoda,
Crustacea), the Protozoa, and the Rotifera (Aschelminthes).
     Under most conditions, members of these groups account for
more than 90 percent of the total zooplankton biomass, and  probably
do so in Lake Michigan.  Animal groups contributing less to the
plankton biomass in Lake Michigan are Arthropoda:  Insecta, Crustacea
(Mysidacea, Amphipoda), Arachnoidea (Hydracarina):  a few platyhel-
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minths, nematodes,  and  annelids.   Fish eggs  and larvae, more
properly meroplanktonlc,  are  discussed in the fisheries section.
     Among the major groups  of Crustacea, there is a general ten-
dency for the Cladocera to become relatively less prominent as
lakes become colder and more  oligotrophic (and, because of
correlations between these factors and size, as lakes become
larger); rotifers remain  about equal  in importance in relation
to crustaceans in all  cases.   Thus, the zooplankton of Lake Michi-
§ u u COPiS'iSi.S pi'lmai'liy  O i  prOtOZOanS, C i a u G C c i* a il 3 , COpcpOuS, 5 i"i u
rotifers, with the  largest fraction of the biomass normally made
up of copepods (Wells,  1960).
     Within all  groups, there  is  great taxonomic diversity, a
character that distinguishes  the  zooplankton from, for example,
the macrozoobenthos.  Each major  zooplankton group contains a
large number of species with  very different  responses to environ-
mental conditions and of  very  different quantitative significance
locally and seasonally.  For  these reasons,  it is as difficult to
characterize zooplankton   of  the  Lake as  having a general response
to environmental  disturbance,  such as discharge of waste heat, as
it is phytoplankton.  It  is  worth noting  that many of the principal
zooplankton forms are complex, advanced metazoans.  Because of
highly adapted and  responsive  sensory systems, and because of their
advanced degree of  organization,  they are highly responsive to,
and easily injured  by changes  in  their environment.
     The majority of zooplankton  in Lake  Michigan range in size
between about 50  micrometers  (smaller rotifers and protozoans) and
1 cm (larger cladocerans)  in  length or greater diameter.  Unlike
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phytoplankton, they are all  capable of independent motion,  although
this is not usually vigorous enough to enable them to resist water
currents in the Lake itself, or in the vicinities of intakes and
discharges.  Within a water mass, independent movement of zoo-
plankton may cause considerable change in density with time.  For
example, vertical displacement of single plankters over distances
of several  meters in 24 hours is possible.  Changes in local
density or organisms complicates sampling, and may mean that the
effects of an environmental  change, such as a change in water
temperature, are removed from the original site of the insult.
     Although the capacity of typical  zooplankters to avoid un-
favorable environmental conditions has very clear limits imposed
by their limited mobility, it is not as restricted as it is for
phytoplankton.
     'Because of small size and, in many cases, high reproductive
capacities, some zooplankton respond rapidly to environmental
change through changes in abundance.  In a favorable environment,
certain parthenogenetically reproducing cladeocerans can achieve
an 8 - to 10 - fold increase in population in a matter of a few
days (i.e., doubling times may not be  less than those for the
more rapidly reproducing phytoplankton).  Others, requiring longer
periods for development through successive larval stages (e.g.
copepods), show slower and even delayed responses.  As with phy-
toplankton, the cosmopolitan distributions of many characteristic
species (and the existence of resistant, easily dispersed stages
in their life cycles) make  possible the replacement of "native"
species with "exotics" having competitive advantages under the
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altered conditions.   Such  changes  have  apparently  occurred 1n
parts of the Lake Michigan system  (Beeton,  1965;  Robertson,  1966).
Such replacement is  possibly  unlikely  to  be as  striking for
copepods as for cladocerans or  rotifers:   although the reasons
are not well understood,  the  former  show  a  much higher degree
of geographic specificity  than  the latter,  which  may mean that
one species of copepod  is  less  likely  to  be rapidly replaced by
another as environmental  conditions  change  (Hutchinson, 1967,
r.  fiRfi ff \
r •  - — — ••./.
     With the exception  of one  group  of planktonic copepods
(Cyclopoida) and a few specialized  calanoid copepods   and clado-
cerans (Leptodora and Polyphemus),  the  food of major  zooplankton
is primarily suspended particulate  organic matter —living  cells
of phytoplankton, or at  least organic detritus originating from
phytoplankton biosynthesis.   Most  zooplankton feed with highly
specialized mechanisms for filtering, concentrating,  or sedimen-
tingsuspensoids, each of which  depends  on a high degree of phy-
siological  coordination.  Feeding  rate  and efficiency are strongly
affected by food density, temperature,  oxygen supply, and other
chemical conditions.
     Zooplankton are, in turn,  food for a wide variety of higher-
order consumers, including fish,  insects, and other invertebrates
depending on size and availability  to the predator.
     The primary role of the zooplankton community is as the major
link between the blosynthetic and  energy-fixing function of  the
phytoplankton and the remainder of  the  Lake's ecosystem.  Dis-
turbance of this function results  in  disturbance of secondary
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productivity^ in the entire Lake, most significantly to produc-
tivity of various economically valuable populations of fish.
     All species of fish occurring in Lake Michigan probably de-
pend upon zooplankton for food at least during early develop-
mental stages.  Those which feed extensively on zooplankton
through the adult stage include the alewife, yellow perch, small
centrarchids, such as bluegills and sunfish, most forage species
of small size (members of the family Cyprinidae), sticklebacks,
and darters, and members of the genus Coregonus,  such as the
whitefish, lake-herrings, bloaters, and ciscoes.
     Probably few species of zooplankton are entirely indifferent
to the quality of their food, and most of those that have been
carefully studied are selective, favoring certain species or
materials derived from phytoplankton and rejecting others.  The
nutritional welfare, composition, and productivity of the zooplankton,
therefore, very strongly reflect quality as well  as quantity of
photopl ankton food, and respond strikingly and quickly to environ-
mental changes that affect the composition and abundance of their
food (see, for example, Pacaud, 1939; Lowndes, 1935; Fryer, 1954).
     Species composition of zooplankton of Lake Michigan and
seasonal changes are imperfectly known, and it is difficult to
'The term "secondary productivity" will be used throughout this
 section to refer to productivity of all  heterotrophs,  without
 making distinctions among the so-called primary, secondary,
 tertiary, . . . consumers.  Such distinctions are useful  in
 certain contexts, but not here.
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separate natural  changes in the character of the community from
those resulting from human alteration of the Lake's environment.
There  is some indication that "native" oligothermal  species,
such as Diaptomus (Leptodiaptomus)  minutus,  are being replaced
by more euthermal ones,  such as Diaptomus (Skistodi aptomus)
oregonensis.  and  that certain species characteristic  of oligo-
trophic waters, such as  Eubosmi na (Bosmina)  coregoni , are being
replaced by those characteristic of more eutrophic waters (not
nas*aecav*41t« K a /* a n c o f\ -P + amnŁiv»a^iiv*o   K 11 +• -fnv*  v*o a c n n c a + n v*o c a n +"
I • N. W * I  • W Wt w « • • ** Wt W f* . w w _ . . —
unknown), such as Bosmina longirostris  (Beeton, 1965, 1966, 1969)
Such changes, if  permanent, may reflect quality of the food
supply or changes in water chemistry.  The composition of the
rotifer component of the zooplankton is, with  the exception of
a few large or prominent forms, almost  entirely unknown.
     Studies  of species-composition and abundance of  zooplankton
are complicated by annual and diel  cycles of abundance.  Annual
cycles of abundance appear to be correlated  with factors such as
temperature,  food supply, and predation (as  the spring-fall
pulses of Daphnia in many inland lakes), diel  cycles  (as in 24-
hour changes  in depth-distribution  of populations of  Daphnia)
with changes  in light intensity or  quality.   Whatever the cause,
cycles are well known and sampling  programs  should take them
into account  (Wells, 1960; Gushing, 1951).
     The importance of zooplankton  for  monitoring cooling water
effects follows from two characteristics of  the community:
1.   Ecological status.   It is a central trophic element and
quantitatively significant factor in the Lake  ecosystem.  If
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affected directly, secondary effects will ramify in two directions,
upwards, toward the primary productivity of the phytoplankton,  on
which it exerts a complex regulatory effect through grazing,  and
downwards, toward fish and other animals and the secondary pro-
ductivity of the entire ecosystem.
2.  Sensitivity results from small size and high reproductive po-
tential.  (High reproductive potential may also negate sensitivity
by permitting rapid replacement of individuals destroyed by con-
denser passage.)
    On the other hand, it is not an easy community to study because
of taxonomic confusion in some of the groups, because of the  dif-
ficulty of maintaining most species under laboratory conditions,
and because of numerous problems in estimating abundance in field.
    Environmental changes affect zooplankton by altering certain
physiological rates:  of respiration, digestion, reproduction,  and
other similar processes, probably in age-specific ways.  These
changes are then reflected in properties of the entire community,
such as total respiration, total productivity, rate of change in
biomass, and species composition.  Individuals are suitably
studied primarily under laboratory conditions; communities pri-
marily in the field.
Field Studies:  Questions
    The following general questions should guide field studies
of the effects of thermal discharges on zooplankton populations:
1.  What changes have occurred in the species composition of the
    affected community?
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    a.   In the relative biomasses  of the various  species  com-
        posing it?
    b.   In the p.atterns of seasonal  change that characterize
        its species composition?
2.   What changes  have occurred  in  the productivity of the affected
    community?  What changes  in fractional units  of productivity
    furnished by  the major components?  What changes in the
    seasonal  distribution of  productivity?
3.   How are the above changes related to changes  in the character
    or  behavior of the phytoplankton community?  How, for example,
    has the food  supply of major  elements  in the  zooplankton
    community been affected?
4.   What is the character and behavior of  the zooplankton community
    in  the Lake as unaffected by  man, or,  what was the condition
    of  that part  of the Lake  prior to thermal discharge?   Two sub-
    sidiary questions are implied  here:
    a.   Is the discharge a factor  that disturbs the stabilized
        state of  the Lake, if indeed its state is stabilized?
    b.   How does  the discharge  interact  with other control 1able
        impacts,  such as chemical  pollution, to modify or amplify
        the effects?
Field Studies:  Implementation
1.   Standard  Samples
    a»   Location  and number of  samples (see  sections on
        phytoplankton).
    b.   Collection and treatment of  samples
        1)  For species determination and  enumeration, evaluation of
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        biomass by dry weight, settled volume, total carbon,
        total nitrogen, or any other destructive analysis,
        samples are best collected with a metered townet (or
        isokinetic pumping of water') to obtain an integrated
        sample from the top to the bottom of the water column
        (except where vertical distribution is the subject of
        study) so that results can be expressed as quantity
        per unit area of lake surface.  If several kinds of
        gear are used, they should be standardized by compari-
        son at a given location and time.

    2)  Townets (or strainers for pumped samples) have a mesh
        size too coarse to capture smaller zooplankton, such
        as most of the rotifers, copepod nauplii, and smaller
        cladocera.  Smaller forms are probably best studied
        quantitatively in whole water samples; zooplankton may
        range down to diameters of the order of 50 micrometers,
        as noted above.
    3)  For specific analyses, the catch should be subsampled.
        The best technique for handling standard zooplankton
        samples is to preserve the entire sample so as to main-
        tain the identity of all animals.  This may be a two-step
A properly used townet may come close to being isokinetic at the
orifice, although it probably will never achieve that ideal; a
townet often results in damage to the organisms.  Volumes can be
controlled better with pumped samples, but the apparatus is more
complicated, subject to malfunction, and intake avoidance may
still be a significant problem.

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process (anesthesia  plus  fixation)  and varies  depending
upon the kind of zooplankters  in the sample.   This  is
followed by a preliminary concentration of the catch and
removal of a true aliquot for  species determination and
enumeration (by age-class if possible: see below).   Re-
moval  of material from this  aliquot (for counting,  for
diagnostic purposes—dissection, making mounts for micro-
scopic examination,  etc.) must not  change its  composition,
because the residue  1s preserved as a voucher.  Correct
determination of field abundance and composition of zoo-
plankton may require additional  collection of  specimens
at the same locality, based  on data from the  aliquot (some
organisms require examination  in the living condition, and
some require fixing  or preservation with special precautions
for competent determination).
    After removal of the  aliquot, the residue  of the sample
should be dried at low temperature or under vacuum,  and pul-
verized for storage  and destructive analyses.   Data should
be accumulated for eventual  calculation of conversion
factors (and their variances)  relating total  carbon, total
nitrogen, total dry  weight,  and counts by species,  to  save
effort in later similar studies.
    Dry material retained will be useful for  additional
                                           ••
destructive analysis, for example,  for radioactivity,  heavy
metal  content, or chlorinated  hydrocarbon content.   Useful-
ness will be maximized if careful attention is given to
conditions of preparation and  storage.
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4)  Sampling errors.  When developing data over areas  using
    large integrated samples (hundreds of liters),  replica-
    tion at a station is probably unnecessary because:
    a)  true errors of sampling for large samples  will  be
        insignificant;
    b)  errors due to horizontal  nonhomogeneous plankton  dis-
        tribution ("patchiness")  will not be correctly  esti-
        mated by simple replication of long tows or pumping
        runs.  Major sampling errors in counts, determina-
        tions of dry weight, carbon content, etc.,  will  ori-
        ginate  primarily in aliquotting or subsampling,  and
        here replication is required.  The degree  of replica-
        tion is determined by variation in the samples  and
        by rigorous testing of the subsampling procedures;
    c)  other errors will originate in poor calibration  of
        the sampling equipment as it measures sample volume.
        Calibration should be performed regularly  to insure
        a high level of precision;
    d)  95 percent confidence limits for means, based  on  sub-
        sampling replication should be presented with  all  results
        However, if stations are  to be compared to  stations  in
        order to detect changes which may have occurred  over  a
        more limited geographic distance, or to substantiate
        possible vertical variation, replication at sampling
        stations may be required, depending upon the sizes  and
        nature of the samples.
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   c.   As  soon  as  possible,  the  above  scheme  should  be  implemented
       with  regular sampling along  16-mile  transects  in  unaffected
       areas in each of  the  geographic regions  of the Lake  (as
       listed in the section on  phytoplankton)  on a  regular monthly
       schedule and maintained  indefinitely to  provide  a baseline
       for evaluation of future  conditions.

    d.  Such  techniques should generally apply to  on-site
       studies  and monitoring programs.
2.  Productivity.
        No single  measure  equivalent  to   14C-uptake  (primary  pro-
   ductivity)  is  currently available  to  provide  information   on
   productivity in a  population  of  consumers.  Techniques  involving
   use of ATP  ("adenosine  tri phosphate) are  currently  under develop-
   ment to provide this  important information.
        Secondary  productivity of a single-species population  can
   be laboriously  computed through  data  on  birthrates,  mortality
   rates, growth  rates,  respiratory rates,  age-structures,  etc. in
   various combinations.   Most of these  data are  exceedingly  diffi-
   cult to obtain.   In the absence  of direct determination  of
   secondary  productivity, indices  from  standard  samples will
   provide some information  on some of the  components of the  zoo-
   pi ankton.
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     Faithfully through time, at all  stations on the Lake,  a
picture of the normal seasonal pattern of zooplankton productivity
characteristic of each of the various geographic regions will  be
obtained, which will serve as background or standard of comparison
against which changes produced by thermal discharges can be
evaluated.
     These indices are ratios of numbers of individuals at  two
different stages of the life cycle (thus at two different ages).
They are related to rates of change in population size, or  to
turnover rates.  In conjunction with  information on absolute popula-
tion size, and compared within a species through space and  through
time, the following routine measurements may shed light on  zooplankton
productivity:
a.  Average number of broodpouch eggs per parthenogenetic female
    in many cladocerans (especially species of Daphnia).  In most
    cladocerans, there are no strikingly distinct juvenile  stages,
    and ages can only imperfectly be  inferred from size.  The
    broodpouch egg, however, is a well-defined age'category, and
    the number of eggs carried is related to the rate of addition
    of new individuals to the population.
b.  Proportions of adult females (or  of all females) carrying
    ephippial eggs (agains, in Cladocera, especially Daphnia).  The
    significance of production of ephippial eggs in cladocerans is
    not well understood.  Poor nutrition is thought to stimulate
    production, and appearance of ephippial eggs is thought to be
    an indication of overcrowding and incipient population  decline
    (Hutchinson, 1967, p. 597 ff.).
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c.    Relative number of female (copepods)  carrying egg sacs.  As
     in a.,  this is a measure of the rate  of addition  of new
     individuals to the population.
d.    Average number of eggs  per sac(female copepods).   There  1s
     little  information on  the significance of the number of  eggs
     per sac, but along with the frequency of gravid females  in
     the population, it 1s  a measure of the potential  rate of
     increase.
e.    Ratio  of copepoditss  tc numbers of adults in a cupepod  popu-
     lation.  This is related to mortality rate between the
     average copepodite and  average  adult  age, and may provide  in-
     sight into the rate of  predation on the population.

     Ratios  of numbers of nauplii  to copepodites to adults serve
     a similar purpose, except that, at present, it is not generally
     possible to identify copepod  nauplii  to species;  it is neces-
     sary to work with the  entire  population of copepods without
     regard  to possible specific variation.  Wherever  the popula-
     tion consists of more  than one  dominant species,  unambiguous
     interpretation of changes in  ratios of nauplii to later  stages
     of the  reproductive cycle will  be impossible.
 f.  Similar indices should  be developed for populations of plank-
     tonic rotifers; rotifers, depending on species, produce  both
     parthenogenetic and sexual eggs, which are often  distinguish-
     able and countable.
Laboratory Studies: Questions
     The principal objectives of a program of laboratory investi-
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gations of zooplankton are to improve understanding of the re-
sponses of the organisms to unnatural patterns of temperature
elevation, both the momentary ones of relatively great magnitude,
such as are experienced by organisms passing through the condensers
of a plant, and those more prolonged but of lesser magnitude, as
may be experienced by organisms entrained in a discharge plume.
Study of entrainment effects is discussed in another section.
     Aside from injury from direct exposure to. heat, a variety  of
indirect effects might be expected on zooplankton, such as those
that would follow from direct effects on the phytoplankton,  af-
fecting the source of food.  Until the effects of thermal  dis-
charges on phytoplankton are more clearly understood, it is not
possible to propose specific guidelines for laboratory investiga-
tions of the responses of zooplankton to changes in the quality
of food.
1 .   Food Preference
     a.  What is the principal  food for zooplankton species
         seasonally and throughout development?  What preferences
         or requirements are revealed by differences in the compo-
         sition of the zooplankton species?
     b.  What replacements among species, or shifts in dominance,
         are likely to follow changes in the composition of the
         phytoplankton (such as a shift from dominance by one
         species of diatom to dominance by another)?
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                           Mi'crobenthos

Introduction

    This term is applied to communities of microscopic organisms
which exist on the lake bottom or at the interface between the lake
and land.  Such communities are complex and composed of primary pro-
ducers belonging to several major algal divisions and consumer organ-
isms including Protozoa and representatives of several invertebrate
groups,   characteristic communities tend to develop on substrate types
and are  often designated as:   epiphytic (occurring on plants),
epilithic (on rocks), epipelic (on soils), psammonic (among sand
grains).  The general term periphyton is often applied to coarser,
more obvious forms.
    Due  to difficulties in quantitatively sampling these communities,
they have  remained rather poorly known with the exception of nuisance
causing  periphyton growths.  Limited observations indicate that such
communities occur to depths of at least 30 m in Lake Michigan.  Many
species  are present which are apparently obligate cold stenotherms
(Stoermer, in press). Certain elements of this "glacial relict"
flora  and fauna apparently find refuge in Lake Michigan below the
level of the thermocline during the summer months.
    Because the primary producer component of these communities is
much more concentrated than the plankton, they provide a rich food
source for invertebrate animals.  The importance of these communities
to the total ecology of the Lake has not been adequately investigated.
Observations, however, indicate that areas of benthic  algal  growth
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 are  favored  feeding regions  for  adult  fish  of  many  species,  furnish
 a  place  of refuge for the  young  of  some  species,  and  are  nesting
 grounds  for  others.
     Primary  concerns  regarding  thermal effects  are  damage  to  indigenous
 stenothermal  communities  by  plume  impingement  and facilitation  of
 growth  of  nuisance periphyton,  C1adophora in particular,  in  the
 eutrophied nearshore  zone  (Neil,  1974; Griffiths, 1974).
 Approaches
     Because  of  the present inadequate  state of  knowledge,  extensive
 preliminary  reconnaissance is  necessary  followed  by detailed  observa-
 tion  of  characteristic community  types.  Suggested  phases  of  this
 process  include:
 1.   An  intensive  visual  survey  should  be made  of  the  region which
     could  conceivably come under  the influence  of heated  plumes.
     This survey should include  shoreline, and  bottom  to a  depth of
     at  least 20 m.  Sampling of  communities should  be  accomplished
     at  this  time.  It is  imperative that personnel  sampling are
     thoroughly  familiar with community types and  appropriate  sampling
     methods.  At  most sites, work will be accomplished by  SCUBA divers.
     Output should be  detailed  maps  of  substrate types  and  comprehen-
     sive lists  of the fauna  and  flora  characteristic  of substrate
     types  and depths.
>.    On  the basis  of this  information,  a  detailed  study plan  should  be
     designed and  submitted to  appropriate agencies  for review.  A
     study  plan  should demonstrate  adequate  sampling of community
     types  with  depth  and  distance  from the  effluent.   Sampling  inter-
     val  should  be not less than  monthly. Certain  habitats  may be
     closed to sampling by  ice  during the late  winter  season.
                                 158

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Parameters should include:
a.  Population abundance and community structure  estimates
   similar  to those developed for plankton  communities.
b. Standing stock biomass estimates.
c. Productivity and growth rate estimates.
      It is  suggested that measurements of biomass  and  productivity
be obtained from naturally occurring communities rather  than  from
those developed on artificial substrates.   Such  estimates  require
innovative  sampling techniques and the use  of  in si tu  enclosure
experiments best accomplished by SCUBA divers.   Artificial  sub-
strates may be used as a measure of trends, but  should not  be  re-
garded as quantitative or representing natural conditions  in  the
Lake.
      Another problem is transfer of materials  from  the plankton to
benthic habitats.  This problem is also  important  to  investigations
on macro-invertebrates and fish as well  as  microbiological  communities
Since certain of the studies are best accomplished  with  the work
outlined above, they are discussed in the following sections.
                      Particulate  Fallout
      Planktonic organisms which pass through or  are influenced by
the  thermal effluent from a power plant  eventually  die and  sink to
the  bottom  of the Lake as do plankters in undisturbed  areas of the
Lake.  Many of these organisms are consumed or decomposed  during
theirdescentwhi le others complete the fall to the  bottom  and  become
part  of the sediments.  If the effects of a power  plant  effluent
result in death of planktonic organisms, one might  expect  dead
organisms to rain down from the plume in greater numbers  in the
                               159

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vicinity of the plant, than in undisturbed areas.  This could
result in an accumulation of organic matter on the bottom which
could either enhance the bottom fauna or create an oxygen demand
and subsequent depletion, limiting bottom organisms.   If the pro-
duction of planktonic forms is stimulated by the effluent, deposi-
tion might not occur in the immediate vicinity of the plant, but
may be shifted further downstream.  In either case, measurement of
the fallout of particulate matter from the water column would pro-
vide useful information concerning the influence of the power plant
on the planktonic community and, in turn, its influence on the
benthic community.
     It is suggested that a series of sediment collectors be deployed
to measure the rate of particulate fall  from the water column.  Col-
lectors could be placed at the ten stations proposed  above for
detailed study of phytoplanktonic productivity and, should also be
near stations sampled for benthic organisms.  Sediment collectors
could be deployed and retrieved on a regular basis coincident with
monthly plankton sampling.   Analyses should be performed on the
particulate material to determine the substance collected and or-
ganic carbon content.
                      Benthic Respiration
     Another measurement closely allied  with particulate fallout is
rate of oxygen consumption in bottom sediments.  Whether the oxygen
is consumed by macrobenthic forms or by  microbial organisms is of
minor concern.  What is important is a comparison of  the rate of
consumption to re-oxygenation.  In areas that have been organically
enriched, oxygen consumption generally occurs at a rate greater
                                160

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than In an unenriched area.   Furthermore, in an area organically
enriched either naturally or from power plant stimulated fallout,
and, warmed by a thermal  effluent, oxygen consumption may be in-
creased as a result of both  stimuli.
     Measurement of benthic  respiration yields information on the
problems discussed above.  Technique  for rn_ si tu  respiration ap-
propriate for this study  have been described in the scientific
literature.  The apparatus could be set out with the sediment
       m A v»<\^v»4/\»/rt/^ a ^ +• *•
       I I %•* I W W I I V« * W V4 IA I W V
rates combined with the particulate fallout data would yield valuable
information to evaluate effects of a power plant on the benthic
ecology of Lake Michigan.
Priority Research
     This subcommittee has expressed its ideas regarding research
necessary to understanding the effects of thermal introduction into
Lake Michigan in the preceeding sections.  From their knowledge,
they do not believe that existing data will get at some of the more
serious fundamental problems in this area.  They therefore suggest
that the following research be strongly considered and that it be
categorized as follows:
Category 1 . Basic research necessary to implement or fortify ongoing
and/or essential studies.
     1.  To develop standard reference works in English which
         address the taxonomic aspects of algal communities.
     2.  To develop quantitative knowledge of the physiological
         requirements of planktonic species native to Lake Michigan.
                               161

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Category II.  Basic research necessary to interpretation of results
         of ongoing and/or essential studies.
         To develop, from historical collections and from paleo-
         1imnological studies, temporal and spatial trends of
         populations of plankton which existed in Lake Michigan.
Category III. Special interest questions answerable by further
treatment of existing data or by minor modifications of presently
planned programs.
         To develop, through proposed environmental monitoring
         programs and through the generation of special field
         measurements, information on planktonic populations of
         the following nature:
         a.  mass transport of biomass,
         b.  food chain perturbations.
Category IV.   General regional  support items necessary to facili-
tate cooling water studies.
         To develop basic facilities support (ships, buoys, computer
         systems, etc.,) for the collection, identification and
         analysis of planktonic  populations, especially platform
         and large instrument package support.
                               162

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                       Literature  Cited
Ahlstrom, E, H. 1936.   The  deep water plankton  of Lake  Michigan,
     exclusive of the  Crustacea.   Trans.  Amer,  Mlcrosc. Soc.   55:
     286-299.

Beeton, A.M.  1965.   Eutroph1cat1on  of the  St.  Lawrence Great
     Lakes.  Llmnol.  & Oceanog. 10:240-254.

              1966,   Indices  of Great Lakes  Eutroph1cat1on.
     Great Lakes Res.  D1v.  Univ.  M1ch.  Publ .   15:1-5.

	  1969.   Changes  In the environment and biota  of
     the Great Lakes,  pp. 150-187.   ln_:  Eutrophication:   Causes,
     consequences, correctives.  Washington,  D.C.  U.S.  Nat.  Acad.
     Sci.

Beeton, A.M. and J.  M.  Barker.   1974.   Investigation of the  in-
     fluence of thermal  discharge from  a large electric power
     station on the  biology and near-shore circulation   of Lake
     Michigan - Part  A:   Biology.   Univ.   Wisconsin -  Milwaukee,
     Center for Great  Lakes Studies, Spec. Rep. No. 18.  26  pp.

Benson, A.A. and R.  F.  Lee.  1975,   The role  of wax in  oceanic
     food chains.   Scientific American, 232:   76-86.

Calrnes, J.  1972,  Coping  with heated  waste  water discharges
     from steam-electric  power plants.   Bioscience, 22:  411-420.

Gushing, J. H. 1951.  The vertical   migration of planktonic
     Crustacea.  Biol.  Rev.  26:   158-192.

Foerster, J, W.,  F. R.  Trainor and J.  D.  Buck. 1974.   Thermal
     effects on the  Connecticut River:   Phycology  and  Chemistry.
     J. Water Poll.  Control  Fed.   46: 2138  - 2152.


Fogg, G. E.  1965.  Algal cultures  and  phytoplankton ecology.
     Univ. Wisconsin Press,  Madison.   126 pp.


Fryer, G.  1954.  Contributions to  our  knowledge of the biology
     and systematics of the freshwater  copepods.  Schwelz.  Z.
     Hydrol.   16: 64-77.

Goldman, J. C, and E,  J.  Carpenter.  1974.  A kinetic  approach
     to the effect of temperature on algal growth,  Llmnol.
     Oceanogr.  19:   756-766.


Griffiths, J, S. 1974,   Aquatic biological studies Pickering
     Generating Station,  1970-1973.  Report #74-78-H,  Hydro-
     Electric Comm.  of Ontario, Research D1v. (Privately

                              163   .

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     published; see Neil   (1974)  loc.  cit.)

Hohn, M. H. 1969.  Qualitative and quantitative  analyses  of
     plankton diatoms, Bass Island area,  Lake  Erie,  1938-1965,
     including synoptic surveys of 1960-1963.   Ohio  Biol.Surv.,
     N. S., Vol.  3,  No.  1. 211 pp.


Holland, R. E. and A.M. Beeton.  1972.   Significance to  eutro-
     phication of spatial  differences  in  nutrients  and diatoms
     in Lake Michigan.  Limnol.  Oceanogr.,  17:  88-96.


Hutchinson, G. E.  1967.   ATreatiseon  Limnology,  Vol. II.   New
     York, N.Y.  John Wiley & Sons.   Xi  + 1115 pp.

Lowndes, A. G.  1935.  The swimming  and  feeding  of certain calan-
     oid copepods.  Proc.   Zool.  Soc.  Lond.   1935:687-715.


Neil, J. H. 1974.  Cladophora in  the Great Lakes.   Limnos Ltd.
     Report DSS Contract   #OSS4-0171.   62 pp.


Pacaud, A. 1939.   Contribution  a  1'  ecologie des  cladoceres.
     Bull. Biol .   Fr. Beige., Suppl.  25.  260 pp.

Robertson, A. 1966.  The  distribution  of Calanoid  copepods in
     the Great Lakes.  Great Lakes Res.   Div.  Univ.  Mich. Pub!.
     15:129-139.


Rosowski, J. R. and B. C.  Parker.  1971.   Selected papers in
     phycology.  University of Nebraska,  Lincoln.   876 pp.


Schelske, C. L. and E. F.  Stoermer.   1972.  Phosphorus,  silica,
     and eutrophication in Lake Michigan,  pp. 157-171.   In:
     Nutrients and Eutrophication, Li kens, G.  E. (ed.).Amer. Soc.
     Limnol. Oceanogr., Special Symposium Vol. No.  1.

Stewart, W. D. P., G. P.  Fitzgerald  and  R. H.  Burris.  1967.
     I^n situ  studies on  N2  fixation  using  the  acetylene re-
     duction technique, Proc. Nat. Acad.  Sci.(Washington),
     58:  2071-2078.

Stoermer, E. F.  (in press).  Comparison  of benthic diatom communities
     in Lake Michigan and Lake Superior.   Verh.  Int. Verein. Limnol.

Stoermer, E. F.  1972.  Statement.   p.  217-254.
     In:  Conference on Pollution on Lake Michigan and  its tributary
     basin,  Illinois, Indiana, Michigan,  and Wisconsin.   Fourth
     Session, Vol. I. U.S. Environmental  Protection Agency.
                              164

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Stoermer,  E.  F.  and  E.E.  Kopczynska.   1967.
       Phytoplankton populations  in  the  extreme  southern  basin  of
       Lake  Michigan,  1962-1963.   lr^:    Ayers,  J.  C.  and  D.  C.
       Chandler,  Studies  on  the  environment   and eutrophication of
       Lake  Michigan.   Univ.  Michigan,  Great  Lakes  Res.  Div.   Spec.
       Rep.  No.  30.   415  pp.


Stoermer,  E.  F.  and  J.  J.  Yang.   1969.   Plankton diatom  assemblages
       in  Lake  Michigan.   Univ.  Michigan,  Great  Lakes  Res.  Div. Spec.
       Rep.  No.  47.   268  pp.

Stoermer,  E.  F.  and  J,  J.  Yang.   1970.   Distribution  and  relative
       abundance  of  dominant  plankton  diatoms  in Lake  Michigan.
       Univ.  Michigan,  Great  Lakes  Res.   Div.,  Publ .  No.  16.   64  pp.

Strickland,  J.  H.  D. and  T.  R.  Parsons.   1963.   A  practical  handbook
       of  seawater analysis.   Bull.  Fish.  Res.  Bd.   Canada,  No. 167.
       311  pp.

Utermtihl,  H.   1958.   Zur  Vervolkommung  der quantitativen  Phytoplankton
       Mitt.  Int.  Verein.  Limnol.   9:  1-38.

Vanderhoef,  L.N.,  B. Dana,  D.  Emerick,  and R.  H. Burris.   1972. Acety-
       lene  reduction  in  relation   to  levels  of  phosphorus  and  fixed
       nitrogen  in Green  Bay.   New  Phytol.    71: 1097-1105.

Vaughn, J.  C.  1961.   Coagulation  difficulties  at the  south  district
       filtration  plant.   Pure  Water   13:  45-49.

Vol1enweider,  R.  A., M. Munawar,  and  P.  Stadelmann.   1974.   A  com-
       parative  review  of phytoplankton  and  primary  production  in
       the  Laurentian  Great  Lakes.   J.  Fish.  Res.  Board  Canada,
       31:   739-762.

Wells,  L.  1960.   Seasonal  abundance  and  vertical movement of  plank-
       tonic  Crustacea  in Lake  Michigan.   U.  S.  Fish  & Wildlife
       Service.   Fishery  Bull.  60:  343-369.
                                165

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               SECTION  VI



MEASUREMENT OF THE  EFFECTS  OF  COOLING  WATER



          USE ON  MACROZOOBENTHOS

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 Section VI.  MEASUREMENT OF THE  EFFECTS OF COOLING WATER USE ON MACROZOOBENTHOS

                           Table of Contents
Foreword    .    .    .    .    .    •    •    •    •    •      •    •   .171
Introduction	171
Macrozoobenthos  of Lake  Michigan	171
Biology of Selected  Lake Michigan Benthos	173
        Pontoporeia  affinis	173
        Oligochaeta	175
        Chironomids	177
        Fingernail clams	178
        Opossum  shrimp  	179
Role of Zoobenthos in The  Ecosystem	181
Benthos As Indicators of  Environmental  Qualtiy	184
Response  of Benthic  Animals  To Environmental  Stimuli   .     .    .187
        Physical  Factors	187
               Depth	187
               Substrate	188
               Water  Movement	190
               Temperature	.191
               Light	193
        Chemical  Factors	194
Concerns  For The Macrozoobenthos As Related To  Cooling Water Use.195
        Experimental  Questions	197
        On-site  Pre-operational  Studies	197
        On-site  Operational  Studies	199
                                 168

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                           Table of Contents
     Off-site  (Lakewide) Studies Related to Macrozoobenthos  	  200
Principal  Problem Areas in Understanding Effects of Cooling
Water Use  on  Benthos   	  	  201
     Natural  Environmental Factors	202
     Effects  of Other  Discharges  	  203
     Sampling Problems	204
     Determination of  The Role of Benthos At Study Sites   	  206
Objectives of Measuring Environmental Conditions and Responses   .   .   .   .206
Benthic Study Field Methods 	  207
     Collection	207
                                                                   i
     Separation	  208
     Sediments	  209
     Mapping  of Sediments	210
     Laboratory Analysis of Sediment  	  212
     Sediment Chemistry  	  213
     Supporting Information 	  214
     Sampling Design	215
          Establishing Stations	215
          Fixed Grid	216
          Selection of Reference Area(s)	216
          Station Identification  	  216
          Station Distribution and Spatial Interval 	  216
          Sampling Frequency	217
          Number of Sampl es	217
                                    169

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                     Table of Contents

Laboratory Techniques  	  218
Data Presentation     	219
     Generic and  Specific  Identification  	  219
     Biomass	220
     Diversity Indices	220
Research Needs And Controlled Experiments 	  221
Priority Needs And Research   	  223
Literature Cited	228
                                170

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Section VI. MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
                        MACROZOOBENTHOS
                           Foreword
All comments received regarding this paper during the period of
solicited review have been incorporated into the text.
                          Introduction
    In some lakes  zoobenthos  is  sparse and therefore its  role
in the lake's  ecosystem appears  insignificant.   However,  the zoo-
benthic standing crop of Lake Michigan is extraordinarily large
(179 kg/ha) compared with other large and deep  lakes in North
America (Alley and Powers, 1970)  or with lakes  all  over the
world (Hayes,  1957).  Zoobenthos  are important  in energy  transfer
and serve two  major functions:  food conversion and nutrient
recycling.
    Macrozoobenthic organisms are characteristically less mobile
than many aquatic  organisms and therefore integrate environmental
stress over time.   Their relative abundance and community structure
are indications of the quality of their environment:  water and
sediments.   Changes in benthic communities often are more easily
measured than  in communities  or populations of other aquatic
organisms.
                   Macrozoobenthos of  Lake Michigan
      The profundal  macrozoobenthos  of Lake Michigan  is made  up
 largely  by  members  of  five taxonomic  groups:
                                 171

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    1.  Amphipods  (Amphipoda)
    2.  Segmented worms  (01igochaeta)
    3.  Midge larvae   (Chironomidae)
    4.  Fingernail clams  (Sphaeriidae)
    5.  Opossum shrimp  (Mysidacea)

    These groups are also dominant in the sublittoral zone, but
other taxa are found with them.  These five groups are of greatest
importance in the benthos because the largest area of the lake is
the profundal zone.  The oligochaete, midge and sphaeriid fauna
include several  species, but Pontoporeia affinis is the overwhelm-
ingly important amphipod and Mysis relicta is the only representa-
tive of the Mysidacea  found in the lake.  These two species, which
occur naturally in relatively few lakes in North America and are
relicts of the glaciation which formed Lake Michigan, are very.
important to the support of fish fauna of the lake.
    The littoral areas  in general, and especially rocky shorelines,
embayments, island areas, river mouths and unusual structures,
provide habitats for many other animals such as crayfish, snails,
and the immature forms  of mayflies, stonefiles, and caddisflies.
Since cooling water is  usually withdrawn and discharged into the
littoral zone, inhabitants  of these areas are most likely to be
affected.  Littoral zone benthos is often locally important to
adult spiny-rayed fish  and may be  especially important to the
juveniles of many fish  species which frequent shallow water.  The
contribution of the littoral zone to the lakewide  benthic biomass
is far overshadowed by  that of the sublittoral and profundal zones.
                                172

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    A perspective on the abundance,  depth  distribution and
dominance of amphipods and oligochaetes  in Lake Michigan is pro-
vided by Mozley and Alley (1973),  who report these  animals made
up over 80 percent by number  of those collected in  extensive
surveys of the central and southern  basins during 1964-67 (Table VI-1.)

           Biology of Selected Lake  Michigan Benthos
Pontoporeia affinis.

     Adult Pontoporeia range from 6 to 9 mm in size in Lake Michi-
gan  (Alley, 1968).  Peak mating occurs  in mid-winter and the
female carries the fertilized eggs and embryos within a marsupial
pouch beneath her abdomen.  When released, the young are slightly
less than 2 mm long.  Just after the young are released,the popu-
lation reaches a maximum  (Mozley and Alley, 1973).   Newly released
amphipods can pass through screening devices which  retain adults.
     Size frequency histograms indicate that Pontoporeia living
at a depth of 10 m in Lake Michigan mature in  one year; those
living between 20 - 35 m  require two years to  mature; and those
living at depths greater  than 35 m possibly require three years or
more to  mature (Alley, 1968).  Amphipods  at 10-35 m depths  repro-
duce in  the spring, while those living at greater depths reproduce
intermittently throughout the year.
     While Pontoporeia   frequently inhabit depths less  than 8  meters,
large populations are not normally found  there.  Populations gener-
ally increase with depth  to the 35 m contour where  populations
               f\
average  8,500/m   (or  more) and then  taper gradually to  populations of
1,000 or  less/m  at depths exceeding 180  m  (Powers  and  Alley,1967).
                                173

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Table VI - 1.  Estimates of abundance (number/m2), by depth, of two benthic taxa
              from the central and southern regions of Lake Michigan.  1964 - 67.'
Taxon
Depth
m
Amphipoda 0- 20
21
41
61
Oligochaeta 0
21
41
61
- 40
- 60
-140
- 20
- 40
- 60
-140

Mean
Ani
6,
8,
6,
3,
1,
1,
2,

Central
Number of
mal s
380
477
876
353
389
460
509
520
Basin
Number of
Grap Samples
12
199
116
286
10
196
91
227

Southern
Mean Number of
Animals
2,
4,
4,
3.
2,
3,
2,

544
264
858
137
898
411
171
720
Basin
Number of
Grap Samples
235
160
164
250
229
157
163
248
       ]After:  Mozley and Alley,  1973.

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     Pontoporeia occur over a wide range of sediment types,  but
largest populations are found in silty-sand sediments that permit
easy burrowing and access to organic detritus.   Marzolf (1963)
demonstrated a correlation between numbers  of amphipods and  numbers
of bacteria contained on detrital  organic substrate.  Several
investigators theorize that the major nutritional  source is  bacteria
which decompose detritus, rather than detritus  itself.   Vertical
migrations of several meters into  the water column are  common  for
a small percentage of the Fontupureia population during hours  cf
darkness and to a lesser extent during the  daylight hours (Marzolf,
1965; and Wells, 1968).

01i gochaeta
     Several species of segmented  worms are abundant in Lake
Michigan.  In general, the ratio of amphipods to oligochaetes
shows a north to south gradient, with oligochaetes more abundant
to the south.  The dominant oligochaete of  Lake Michigan is
Stylodrilus heringianus in the profundal and transitional zones
(Howmiller, 1972 a).  Limnodrilus  hoffmeisteri  is  most  abundant in
river mouths, deltas, and shallow  water areas (Hiltunen, 1967:
and Howmiller and Beeton, 1970).  Moderate  numbers of Potamothri x
mol dav iens is, P_. vejdovskyi and Peloscolex  f reyi occur  in shallow
water and transitional areas and Tubi fex tubi fex are often rather
common lakewide at a depth of 40 m (Hiltunen, 1967).  Brinkhurst
(1969) points out that distribution maps for the pollution tolerant
tubificids, Peloscol ex mul ti setosus , Limnodri 1 us cervix, and L_.
                           175

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maumeensis essentially correspond to the locations of the largest
cities on the Great Lakes with the exception of Chicago.  In Chicago,
sewage is discharged to the Illinois River and is diverted away
from Lake Michigan.  Other oligochaetes locally important in
Lake Michigan are Limnodri 1 us spiral is, Aulodrilus pluriseta,
Limnodrilus claparedeianus, Peloscolex variegatus and P_.  superiorensis
(Mozley, 1974).  Forty species of microdrile Oligochaeta are known
from Lake Michigan (Hiltunen, 1967).  Eleven of these species were
not found in Green Bay by Howmiller and Beeton (1970).   They found
two species not reported by Hiltunen.
     Many species of oligochaetes breed over a wide seasonal range
with a peak in the summer months.  Fertilized eggs are  deposited
in cocoons in the sediments and a life cycle is complete in 12 to
18 months.  This pattern can be modified by local conditions
(Kennedy, 1966), hence time of recruitment will vary from place
to place.
     Recent Russian work (mentioned in Mozley, 1974) indicates
possible generation times of two months for Tubifex tubifex and
Limnodrilus hoffmeisteri, while other tubificid species  require
more than one year for sexual maturation.   Peak numerical popu-
lations undoubtedly occur in different months and there  is a lag
between emergence of the embryos and growth to sizes retained on
screening devices.  Various investigators  have reported  peak counts
from February to October.  Oligochaete biomass in Saginaw Bay of
Lake Huron fluctuated from 3.0 g/m2 in June to 8.4 g/m2  in August,
to 0.5 g/m2 in October of 1969 (Schneider  et al., 1969).  To date,
                             176

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the data on seasonal oligochaete population fluctuations do not
lend themselves to generalization, e.g., a fall maximum has been
reported in Lake Michigan littoral zones while November minima
have been reported for S_. heringianus.
     Attempts to correlate oligochaete populations with sediments
on the basis of particle size alone have usually failed.  Organic
content may be more important than particle size and the incom-
pletely understood relationship between the tubificid species and
the microbial flora of the organic material may be the key to dis-
tribution and abundance.
Chironomids
     Heterotrissocladius  and Prod ad i us  are the only midges found
in important numbers in the profundal zone of Lake Michigan.  They
are also found in  the sublittoral  zone where Heterotrissocladius
is represented by  at least two species.  In the littoral zone and
areas to 20 m depth the midge fauna is dominated by Potthastia,
Cryptochironomus,  Monodiamesa tubercul ata, Paracl adopelma, Procl adius.
Tanytarsini, Chironomous  attenuatus. Ł. antharacinus and other
Chironomus.  Polypedi1 urn  and Parachironomous can be important
locally.   Generally, members of the Orthocladiinae become more
numerous in the northern  part of the lake, but Psectrocladius cf.
simul ans is numerous in the southern part.  Procladi us and other pre-
daceous midges often occur in company with large oligochaete popu-
lations.
     According to  species preference and water temperature,  midges
emerge as adults to mate  from very early spring  to as late  as
October for Heterotrissocladius.  Midges of the deeper waters are
                                177

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     probably limited to one cycle or less a year, while those 1n
the shallows may go through more than one cycle.  Most commonly,
eggs are laid 1n gelatinous masses which sink to the bottom.  The
first larval Instar 1s usually planktonlc and later Instars oc-
casionally leave the sediments or substrate to swim above the
bottom, especially at night.
     Considering Lake Michigan as a whole, midges are far less
numerous than amphlpods and ollgochaetes and make up a small part
of the blomass.  However, at depths less than 10 m, chironomid
larvae may be the dominant macrobenthic animals.  Heterotrissocladius
may be 100 to 300 times less abundant than amphlpods and ollgo-
chaetes In an average sample taken from the profundal zone.
     The Ch1ronom1dae exhibit the most pronounced seasonal  abundance
of the major taxa.  The times of emergence of each species  and
recruitment of early Instars Into the size retained in sieving de-
vices are variable and little information is available.  A  July
maximum has been reported 1n littoral areas, probably because
several small species reach screenable size only just before summer
metamorphosis.
Fingernail Clams
     Twenty species of Sphaeriidae are known from Lake Michigan
(Heard, 1962).  Generally, Pisidium numerically dominate the
sphaeriid fauna at all depths.  Sphaerium nitidum and S^. striatinum
forma acunrlnatum occur with Plsidlmn, but only in local areas do
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the numbers of Spharerlum exceed the numbers of Pisidium in any
sample.    Maximum spaeriid populations  are found between 30 and
60 m.   Pisidium is commonly observed carrying its young in the
mantle cavity during late summer, but there is no firm information
on population fluctuations with season  (Heard, 1960).  If the young
were released concurrently, large increases in numbers should occur
over short periods because the young are large enough to be retained
in the most commonly used sieve sizes.
Opossum  Shrimp (Mysis relicta)
     Mysids are considered epibenthic.   In shallow and intermediate
depths they spend daylight hours on or just above the sediments
and in deep water some of the animals may be considerably above
the sediments.  At night large numbers  (probably all) move upward
into the plankton.   Apparently their sensitive eyes and backward-
darting  escape reaction enable the animal to elude capture by
benthic  grabs most of the time.  Because of their habits and
mobility, methods, to determine the effects of pump entrainment on
the populations would be similar to methods suggested in Section VIII,
Entrapped and Entrained Organisms.
     Reynolds and DeGraeve (1972) reported monthly estimates of
mysid density in southeastern Lake Michigan.  Using a plankton net
attached to a benthic sled, animals were not captured at depths
of 9 m.   Density was usually low at depths between 18-37 m,
moderate between 46-55 m and relatively high at 64 m and deeper.
Average  population density at depths from 18-73 m ranged from
  ^Hiltunen, J., 1974.   Personal  Comm.  Great Lakes  Fishery Laboratory,
   U.S. Fish and Wildlife Service,  Ann  Arbor, Michigan.
  2Beeton, A.M., 1975.   Personal  Comm.
   University of Wisconsin,  Milwaukee,  Wisconsin.
                             179

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0.3/n)2   in  December,  to  64.2/m2   in August.  Maximum density was
      2
228/m .   These  estimates  are most likely  too small as the water
stratum  from  the  bottom  to  a height of  10-15 cm was not sampled.
Reynolds  and  DeGraeve (1972) also suggest  that sizeable numbers of
adults apparently move from the  deep water areas  to relatively
shallower water (18-64 m)  in winter where  they breed and subsequently
release  their young  in April and May.   At  greater depths there ap-
pears to  be  some  breeding  and  recruitment  throughout the year.
General  population abundance was lowest in December and highest in
mi d-summer.
      Mysis  from  Lake Michigan range in length from about 3 to
27 mm.  Incubation time  of  the young in the marsupium may be no
longer than 2 or  3 months.  Brood  size  declines with development
from  egg  (mean, 14.1/female).    At release, young are  2-3 mm
in length.
      Mysids are reported to feed  on organic detritus and pelagic
diatoms in Lake Michigan (McWilliam, 1970).  This differs  in part
with  observations  from Char Lake, N. W. Territories, where feeding
on inorganic particles and diatoms on a moss  substrate was reported
by Lasenby and  Langford  (1973).  Apparently the microbiota or
absorbed  film of  colloidal organic matter  attached to the inorganic
                    s
particles are gleaned  in the gut.  The authors  reported that mysids
feed  on Daphnia,  other cladocerans, and components of plankton
while in  the water column at night.
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                Role of Zoobenthos In The Ecosystem
     The macrobenthlc invertebrates of Lake Michigan are part of
the energy transfer system and serve two major functions:   recycling
nutrients from the sediments and deep water areas into the photo-
trophic zone, and converting lower organisms into a food form
available to higher organisms.
     Oligochaetes (and other invertebrates), burrowing and feeding
in sludges and sediments, pass the converted materials upward to
the sedimsr.
           t-watsr interface where they are more susceptible to
breakdown and assimilation by other processes.   Without such re-
cycling, nutrients and other chemical  elements  deep in the sediments
would be essentially unavailable.
     Mysids remain on or near the  bottom part of the time and at
other times migrate vertically many meters into the water column.
During migration their fecal pellets redistribute minerals derived
from the bottom materials.  To a more  limited extent this same
phenomenon occurs with Pontoporeia and some midge larvae.  Fish,
feeding on these migrating organisms,  contribute to the same
cycling phenomenon.
     The more obvious energy transfer  role is that of converting
organic detritus (or the microflora and fauna associated with it)
into a form directly available to  fish of recreational and com-
mercial importance, or for smaller fish which in turn are food
for the larger species of value to man.
     Oligochaetes are rarely reported  as important fish food, but
because these animals breakdown  rapidly during digestion, their
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importance may have been overlooked.  Midges are well recognized
as food for small fish and have been reported by Rolan  (1972) as
food for at least 19 species of fish found in Lake Michigan.  His
listing did not include many species of Lake Michigan fish known
to consume midges.  Rolan also reported six species of Lake Michigan
fish as known sphaeriid feeders; his list did not include spottail
shiners, alewives, deepwater and slimy sculpins, or Catastomidae,
all known sphaeriid feeders.  Wells and Beeton (1963) recorded
fingernail clams (Sphaerium nitidum) in the stomach of Lake
Michigan bloaters (Hiltunen, J. K. 1975, Personal Communication).
     Pontoporeia affinis and Mysis relicta are, for several reasons,
the most important macroinvertebrate food for fishes of commercial
and recreational value in Lake Michigan:  their abundance, wide dis-
tribution, high percentage of benthic biomass, availability to fish,
and the preference of many  fish species for these organisms at
some stage of  the fish's development.
     Henson et  al.,   (1973) summarized  much of the literature
dealing with the  food habits of the important  fish in Lake Michigan
Important forage  species such  as  smelt  and sculpin. depend heavily
on Pontoporeia.   The  diet of longnose suckers can be as high as 63
percent Pontoporei a   and the  intake of the white sucker  is about
30 percent Pontoporeia.   Both fishes  are commercially important.
Young  lake trout'and  burbot feed  on this amphipod as do the deep
water  chubs which are in turn  eaten by  the larger trout.   The
diet of whitefish is  comprised  of as much  as  63  percent Pontoporeia.
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     Mysis relicta is the  dominant  food organism for the deep-
water bloater chub and the average occurrence in stomach was 48.2
percent.  Mysis  is important in the diet of smelt and whitefish
and ranks first in volume of food for young lake trout (28-30 cm)
in Lake Superior.   Mysids are eaten also by burbot.
     Sphaeriid clams have been reported by several investigators
as important in the diet of migrating waterfowl, particularly
scaup.  Over-wintering old squaw ducks on Lake Michigan feed
heavily on Pontoporeia  to depths of 20 m.
     The two major benthic energy pathways in Lake Michigan involve
Pontoporeia and Mysis.  The first pathway, based on nutrient input,
goes through the phytoplankton, the zooplankton, Mysis , the chubs
and other forage fish, to the large salmonids.  Because of the cur-
rent abundance of alewives in Lake Michigan and the lesser importance
of Mysis in their diets, Mysis is partially bypassed in this energy
transfer.  The second pathway begins with energy derived from the
organic matter and microbenthos , leads through Pontoporeia.  the
chubs, and numerous other forage fish including the alewife, to the
large salmonids.   Collapse of either the Pontoporeia or Mysis popu-
lations would result in  an energy shunt with  added stress  on the
remaining  cornerstone.   The  ecological outcome would  be difficult
to predict.  Current information  and knowledge of cooling water use
on Lake Michigan  does  not suggest that such  use has affected popu-
lations of these  organisms.
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         Benthos As Indicators of Environmental  Quality

     The relative abundance, species composition and community
structure of benthos are reflections of the quality of their en-
vironment as characterized by chemical, biological, substrate, and
other physical conditions.  Benthic animals are  characteristically
less mobile and therefore are better indicators  of stresses over
time than pelagic organisms.  Environmental stresses are often
reflected in changes in benthic assemblages.   These changes are
often more easily measured than in communities or populations of
other aquatic organisms.
     Oligochaetes have perhaps been more misused as indicators of
aquatic environmental quality than any other  single group.   Upon
discovery of very abundant populations of Oligochaetes, various
investigators, especially those representing  enforcement agencies,
have proposed over-simplified and perhaps naive  schemes of  popula-
tion detection and assessment.  An eminent authority on North
American Oligochaetes, Dr. Ralph Brinkhurst (1965), has stated
categorically, "there is no simple numerical  relationship between
the numbers of unidentified worm species, or  the proportion of all
worms in the fauna, and pollution of any but  the most obvious, and
demonstrably extreme types."  Identification  of  the worms is
essential because the presence of a particular species and  community
structure reflect environmental conditions much  more accurately
than simply the presence of "oligochaetes" alone.
     Brinkhurst, et al. (1968) suggest the indicator value  of some
Oligochaetes in the Great Lakes based on many years of observa-
tions and taxonomic work:
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     1.   Species restricted to grossly polluted areas:
         Limodri 1 us hoffmei steri,  L^.  cervi x, and Peloscol ex
         multisetosus.
     2.   Species often  present in  grossly polluted areas:
         Branchiura sowerbyi,  L^.  maumeensis, and L^ cl aparedianus.
     3.   Present in mesotrophic or eutrophic areas (in the
         classical  sense):   Aulodri1 us. Potamothrix. and
         Peloscolex ferox.
     4.   Characteristic of oligotrophic areas:  Rhyacodri1 us,
         Tubi fex k e s s1e r i  americanus ,  Peloscolex variegatus,
         and  Stylodrilus heringianus.

     The problem with such  lists  is  that contradictory opinions
or modifications continually  emerge.   This  subcommittee feels
the categorization  "restricted to  grossly polluted areas" is too
rigid  and a  more  appropriate  category would be "present in a
wide range of environments, but not  abundant outside polluted
areas".   Tubi fex tubi fex,  Limnodri1 us  hoffmeisteri and Peloscolex
multi setosus  for example,  could be included in that category.

     Brinkhurst, et al. (1968) also  suggest the use of some species
of chironomid  larvae as indicators of  trophic  conditions in lakes,
as have  other  scientists.   The subcommittee endorses efforts to
     also Howmiller and Beeton (1971);  Hiltunen (1967, 1969),
 and Kinney (1972).
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develop this concept  further, especially as it would refer to
specific sites and stresses.  However, local conditions do not
often reflect lakewide conditions in large bodies of water.
     There is universal agreement that such animals as Pontoporei a,
Mysi s , Heterotrissocladius and Sty!odri1 us heringianus are  in-
dicative of oligotrophic situations.  On the other hand populations
of oligochaetes composed of Limodri 1 us cervix, J^.  maumeensi s , and
high numbers of _L. hoffmei steri, indicate saprobic conditions.
Generalizing on the significance of the presence of species where
preference is less clear meets with disagreement.  Similar relation-
ships are recognized  for many other benthic organisms.   It is ac-
knowledged that the presence or absence of certain species and
population trends of  certain species can be meaningful  information
on environmental  quality, provided such information is  interpreted
by an expert thoroughly familiar with the ecosystem.
     Total numbers of individuals or biomass of benthic populations
or communities have also been used as evidence of organic enrichment
of lakes (Alley and Powers, 1970, and Robertson and Alley, 1966).
Biomass measurements  should be employed only with careful attention
to technique since preservation of animals and measurement of
weight have been  so varied that comparison of results  with other
studies may be misleading (Howmiller, 1972b).
     In summary,  at the present time the use of all macrozoobenthic
information in Lake Michigan as an indication of environmental
quality is not an exact science.   However, reproducible results and
reliable, generalized judgments are often possible.  While con-
troversy exists over which populations or assemblages  indicate what
                            186

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environmental  conditions,  there  is  much  agreement on most worm
species-communities  as  well  as  on  Pontoporeia relationships.

     Response  of Benthic Animals  to Environmental Stimuli
Physical  Factors
     Depth
     Most benthic species  in Lake  Michi gan,.do not thrive in the
shallowest water areas  or  deepest  areas  of the profundal zone,
but between those two extremes  their depth distribution is not
sharply limited.  There is general  agreement as to whether a
species is typically shallow water, transitional, or deep water
in habit, but  depth  range  is normally broad.  Rolan (1972) reviewed
the work  of several  investigators  and combined their information
into graphs clearly  illustrating  these generalizations.
     Such depth-related factors  as  temperature, light intensity,
chemistry, turbulence,  sediment  composition and availability  of
food appear to be more  important  than hydrostatic pressure.  Certain
chironomids, dependent  on  ability  to secrete gas for buoyancy before
emerging, may  be limited by  hydrostatic  pressure.
     Shallow areas of unstable  sediments subject to wave action and
turbulence generally have  low macrozoobenthos populations.  However,
recent work (Mosley, S.C.  1974.  Personal communication) using a #10
net indicates  that,  at  least in  midsummer, extremely large populations
of meiobenthos (>micro- and  
-------
collected greacci
been thought to inhabit such areas.
     The data of Mozley and Alley (1973) showing depth distributions
of Amphipoda and Oligochaeta (which made up over 80 percent of the
organisms captured) appear to be representative of the depth  dis-
tribution  of a number of benthic organisms in Lake Michigan.   Other
investigators  (Cook, et al.,  1965; Schuytema and Powers, 1966)
have reported peak numerical populations in Lakes Michigan and
Huron occurring at depths less than 10 m.   These data include
samples from bay and harbor areas not typical  of exposed shorelines
and open waters.   Their data for depths =>20 m are representative
and show numbers  peaking at about 35 m, dropping rapidly to depths
of 80 m, and then leveling off.
     On the sandy, exposed shorelines of eastern Lake Michigan
populations of macrobenthic animals are comparatively sparse at
depths less than   7 m, however chironomids are most abundant there.
Amphipods, sphaeriids and oligochaetes increase between 7 and  13 m
and amphipods and oligochaetes increase further between 22 and 25
meters.  These changes correspond to changes in sediment type  and,
most likely, to accompanying changes in organic content.
     Substrate
     Substrate is one of the most important factors influencing
distribution and abundance of benthic fauna.  Changes in type  and
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abundance of benthos with  depth,  as  described previously for a
sandy exposed shore, corresponded with  changes in  sediment type.
At depths less than 7 m,  coarse  and  medium sands  predominate; be-
tween 8 and 22 m,  fine sands  with some  silt are most frequent; and
between 22 and 25  m, gelatinous  silt and  clay generally become
dominant.  Underwater observations show that sediment types do not
change smoothly with increasing  depth.   Patches of silt and muck
occur in zones where clean fine  sand predominates  (Mozley and Alley
1973).
     Many species  occur over  a broad range of sediment types and
substrates.  Laboratory experiments  have  determined a preferred
substrate composition for  some species.   Other factors equal, the
species will  be found in  greater  numbers  in association with their
preferred substrate in a  natural  situation.
     Median particle size  is  often reported in benthic studies
(See section following on  "Sediments and  Sediment  Chemistry").
Brinkhurst (1967)  feels that  such studies have not been helpful
in explaining the  occurrence  of  oligochaete species.  However,
Henson (1962) found that  the  abundance  of oligochaetes in the Straits
of Mackinac region, when  plotted  against  median particle size, was
nearly a normal curve with the mean  (050) at 3.9,  which is fine to
very fine sand.  Several  authors  have generalized  that oligochaetes
prefer finer sediments to  coarse  ones.   Henson and Herrington (1965)
plotted the distributions  of  25  species of fingernail clams in the
Straits region against depth  and  particle size.  They established
the preference of  several  species for median particle sizes.
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     Evidence from a number of recent studies supports the con-
tention that organic content of sediments may have more influence
on benthic distribution than sediment size.  Brinkhurst (1967) has
found Ilyodri1 us tempTetoni positively correlated with organic
content of sediments, while Peloscolex ferox,   another oligochaete
species, is negatively correlated.  Schneider et al.  (1969) found
that Hexagenia sp. and Chironomus plumosus are positively corre-
lated and Cryptochironomus and Pseudochi ronomus negatively correlated
with organic content of sediments in Saginaw Bay of Lake Huron.
Fenchel (1972) provides insight into the relationship of interstitial
bacterial populations to sediment particle size and nutrient content
of water.
     In general, sorting of the lighter organic sediments following
resuspension by a variety of factors tends to keep the littoral
sediments low in organic content, while sublittoral and profundal
sediments are higher.  Organic content and the associated microbial
fauna may be more important than particle size or other factors
such as depth in governing the distribution and abundance of macro-
zoobenthos.
     Water Movement
     A few benthic species whose usual habitat is quiet water can
adapt to turbulent conditions provided a stable substrate to burrow
into or cling to is available.  Amphipods, certain midge larvae and
snails have such adaptive ability since they can be found, along with
immature stoneflies and certain mayflies and caddisflies, in shallow
areas subject to great turbulence, such as exposed rocky shore or
breakwaters.  Rheophilic organisms adapted to life in flowing streams,
such as caddisflies (Hydropsyche), may colonize the riprap of power
                             190

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plant intake and discharge areas in the lake.   Currents have a role
in bringing food to sessile filter feeders  and also in distributing
the eggs and early instars of several  benthic  insects.
     Movement of unstable sediments appear   to limit the shoreward
distribution  of many species.   Grinding action may limit microbio-
logical  and diatom development  on  such sediments, eliminating a
food source.  Such action can also injure the  animal directly.
Resuspensions of sediments by wave action and  redistribution of
the lighter organic fractions to deeper water  also deprives  organ-
isms living in the shallows of  this food source.
     Discharge of cooling water may produce a  scouring action on
the bottom precluding benthos colonization  around the discharge
structure.  Farther from the discharge, populations of lacustrine
benthic  organisms will  increase.   These animals may benefit  from
fallout  of crippled or dead zooplankton and broken algal cells
caused by p-assage through the pumps,  condensers and discharge
structure.
     Temperature
     The species composition of aquatic communities at all  trophic
levels depends in part on the temperature characteristics of their
environment.  Each species has  upper  and lower thermal limits (both
short and long-term), optimum temperatures  for growth, preferred
temperatures in thermal  gradients, normal temperature ranges, and
temperature limits for various  activities such as mating, ovipositing,
egg incubation, hatching, pupating and emerging.   Aquatic  inverte-
brates are without internal mechanisms for  thermal regulation and,
                            191

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since their surface area is large in proportion to their mass,
their body temperature quickly conforms to the temperature of the
surrounding water.  Thermal conditions are rarely optimal, as
natural variations create conditions either above or below optimum
within a tolerable range.
     Lake Michigan is one of the southernmost lakes possessing an
oligothermic fauna characteristic of colder lakes.  This is possible
since the hypolimnlon is insulated from surface warming by a well-
marked thermocllne and remains cold and well-oxygenated at tempera-
tures near 5C throughout the summer, although surface layers may
warm up to 20C or more.  The warming of the main water mass in
spring and early summer lags the air and watershed temperature to
such an extent that warm water rivers entering the lake may be
10 - 15C warmer than the lake surface waters.
     The glacial marine relicts Pontoporeia affinis, Mysis relicta,
Heterotrissocladius subpilosus Kieffer (Henson et al., 1973); a
possible glacial marine relict, Pisidium conventus (Henson, 1966);
and other oligothermic fauna thrive in the thermal regime of the
hypolimnion and thermocline.
     The southern half of Lake Michigan is generally warmer than
the northern half and because prevailing winds from the sector
south to west produce more frequent upwellings along the western
shore than on the eastern shore, surface temperatures are generally
higher on the eastern side.  During the spring warming phase pre-
viously described, the region of nearshore thermal stratification
with surface temperatures rising above 4C is separated from off-
shore homothermal water at temperatures below 4C by a narrow
outward-moving transition zone (the thermal bar) in which water

                           192

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at maximum density Is actively sinking (vertical  4C Isotherms).
The offshore transport of heat therefore takes place not only at
the surface as the thermal  bar moves outwards but also 1n the form
of heat addition to deeper  layers, gradually warming the hypolim-
nlon from its March minimum near 2C to its summer value near
4C.
     These several phenomena Influence the lake's thermal regime
and tfiu'3 determine ir. part  the species present, their abundance.
distribution, reproductive  activities and productivity.
     The addition of heat to Lake Michigan by cooling water dis-
charges has the potential for changing the structure and metabolism
of aquatic biological communities.  Such changes  may be detrimental
or beneficial.  While the great majority of published investigations
on effects of thermal discharges to the Great Lakes, and Lake Michigan
in particular, demonstrate  negligible environmental effects,
especially for the benthos, scientific prudence dictates caution in
presuming that the effects  of all current and proposed thermal
discharges to Lake Michigan will be negligible.
     Light
     Cooling water discharges may scour bottom sediments and create
increased turbidity locally.  Littoral currents transporting sediment
can provide fresh materials for resuspension by scour.  The extent
to which the resulting decreased light transmission influences
benthos has not been reported.  Light intensity Influences the distri-
bution of some benthlc species directly, regulates the vertical migra-
tions of Pontoporeia (Marzolf, 1965) and Mysis (Beeton, 1959) and limits
                            193

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the water depth to which benthic flora, a food source, can grow.
Segerstrale (1971) demonstrated photoregulatory  dominance over
thermoregulation in maturation of Baltic populations of Pontoporeia.
Chemical Factors
     Few investigations have been conducted to quantify the influence
of chemical contaminants in the sediments on benthic macroinverte-
brates.  Gannon and Beeton (1969, 1971) carried out a series of
laboratory tests with benthic animals using sediments from nine
Great  Lakes harbors. - Sediments from five harbors were toxic to
Ponotoporeia.   Test animals displayed selectivity for the less
contaminated sediments when offered choices.  The U.S. EPA used
data from these tests to establish criteria for identification of
sediments which should be dumped only in confined areas (U.S. Army,
1971).   Contaminants of general concern are volatile solids, phos-
phorus, ammonia, organic nitrogen, chemical oxygen demand, oil and
grease, iron,  lead and zinc.   Oily sediments have been identified
                                            • ifc.
by many authors as influencing benthic communities.
     Johnson and Matheson (1968) associated direct iron toxicity, or
COD associated with iron oxidation, with a lack of tubificid worms
in Hamilton Bay in the vicinity of steel mill discharges.
     Changes in dissolved gases caused by heated discharges may be
more important than currently recognized.  J"h«re are documented  in-
cidents of gas bubble-Disease of fish in heated effluents (Demont
and Miller, 1972) and the laboratory occurrence of gas bubble disease
in three species of bivalve mollusks  held in heated running sea-
water during the winter (Malouf et al., 1972).  Any effects on
benthos would probably be limited to the immediate vicinity of the
                            194

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 discharge.
      Biocides, such as chlorine used to prevent fouling in con-
 denser tubing are known to kill fish (Truchan and Basch, 1974).
 Benthos can be similarly affected when they are resident in the
 zone of residual biocides and time-toxicity relationships exceed
 their tolerance.

 Concerns  For The Macrozoobenthos  As  Related To Cooling Water Use

     Mechanisms  by which cooling water use  causes, significant
effects  on  the  Lake  Michigan  macrozoobenthos community have  not
as  yet been demonstrated unequivocally.   The possible potential
effects  of  use  of Lake  Michigan  waters for  cooling  lead to  the
primary  concern  that  the macrozoobenthos may be so  altered,  reduced
or  eliminated that an energy  shunt  is  created which would result
in  lower  production  of  desirable  forage, game and commercial  fish
or  increased production of  undesirable fauna and  flora, or  both.
     Mechanisms  which could  contribute to  this  primary concern  are:
     A.   Thermal
         1.  Shortened  incubation  periods  resulting in a reduced
             hatch of smaller and  less physically-capable animals,
         2.  Premature  hatching  when  food  sources are not avail-
             able ,
         3.  Premature  emergence  into  unfavorable climatological
             conditions,
         4.  Chronic  conditions  exceeding  temperature tolerances
             of  desirable organisms,
         5.  Conditions favorable  to  organisms  of less value as
             food to  macrozoobenthos  and higher trophic levels,
                              195

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    6.   Conditions favorable  to  parasitic  or  disease
        organisms,
    7.   Conditions favoring  abnormally  high predation,  and
    8.   Stress induced  by  intermittent  thermal  shocks  as
        plumes shift or units  go  on  and off line.
B.  Physical, other than thermal
    1.   Substrate alteration during  construction,
    2.   Substrate alteration by physical interruption  of
        littoral drift,
    3.   Creation of uninhabitable environment due  to  velocity
        of discharge, and
    4.   Increased turbidity by scour.
C.  Chemical
    1.   Direct toxicity by chlorine,
    2.   Direct toxicity by discharge of boiler cleaning
        materials,
    3.   Direct toxicity by cooling tower maintenance  materials,
        and
    4.   Accumulation of toxic metals in sublethal  concen-
        trations.
D.  Intake
    1.   Impingement of large organisms  such  as crayfish on
        screens ,
    2.   Pump entrainment and condenser  passage, and
    3.   Deposition of organisms  killed  or  crippled by  entrain-
        mento
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Experimental  Questions
                    i
     In response to the-concerns  enumerated  above there are experimental
questions to  be answered  or addressed  during investigations into
effects of cooling water  use on  macrozoobenthos.  The questions  are
grouped into  on-site  preoperational ,  on-site operational,  and
off-site lakewide studies.   While  this encourages redundancy, there
are advantages  to the  reader.   There  is  an  inherent responsibility
in planning or  evaluating any  study  to be  sure investigative resources
are allocated wisely  so that the aspects which have the greatest
potential for impact  at the specific  study  site  receive an appropriate
share of the  effort.   Thus  some  aspects  may be addressed only through
literature search while others should  be  investigated in minute  detail.
     In responding to  these questions, the  investigator should
establish the relationship  to  the  macrozoobenthos.  The questions  are
not all-inclusive, nor exclusive of  site-specific considerations.

On-site  Pre-operational Studies
     1.  What  are  the  bottom  contours within  the  study  area  prior
         to construction or operation?
     2.  What  are  the  substrate types within  the  study  area  prior
         to construction or operation?
     3.  Are the  contours  and substrates known  to  an  extent  which
         would  permit  detection of changes  caused  by  construction
         or operation?
     4.  Are the  substrates unique to the  site  or  critical  to the
         survival  and  well-being of important indigenous
         macrozoobenthos?
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 5.  Is the littoral drift known?
 6.  Will the littoral drift be physically altered by
     construction or operation?
 7.  Were the littoral drift, bottom contours, and substrate
     types altered by construction?

 8.  What are the preconstruction or preoperation
     macrozoobenthic populations and communities  in the
     study area?  Species?  Densities?   Diversity?
     Community biomass?  Important species biomass?
 9.  Are the macrozoobenthos  communities known to an  extent
     which would permit detection of change?   Were they
     altered by construction?
10.  Are the macrozoobenthic  organisms  of importance  in the
     diet of local fishes?
11.  Are the local macrozoobenthos unique or  critical  to the
     ecosystem of the water body segment or lake?
12.  Are any of the macrozoobenthos present in nuisance
     quantities?
13.  Are the seasonal behavior patterns and life  cycle
     activities of the important animals known?
14.  What food sources are important to the macrozoobenthos?
15.  Based on plume modeling  and anticipated  operational  modes,
     what macrozoobenthic organisms will be impacted  and over
     what area?
                            t
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On-site Operational  Studies
     1.  What changes have occurred in the bottom contours due to
         construction and operation?  Are the changes important
         to the macrozoobenthos?
     2.  What changes have occurred in the littoral  drift due to
         construction and operation?  Are the changes important
         to the macrozoobenthos?
     3.  What changes have occurred in the substrate type due
         to construction and operation?  Area"!  extŁ"t?  Are the
         changes important to the macrozoobenthos?
     4.  What are the post-operation macrozoobenthos populations
         and communities?
     5.  What changes have occurred in the macrozoobenthos due to
         construction and operation?  Were the  changes statisti-
         cally significant?  Areal  extent?  Are the  changes
         ecologically significant to higher trophic  levels?
     6.  Are any of  the macrozoobenthos present in nuisance
         quanti ties?
     7.  Are macrozoobenthic organisms impinged or pump-entrained?
         In sufficient numbers to threaten appreciable harm to
         populations or communities?  If so, what is fate of
         entrained organisms?
     8.  What is reaction of macrozoobenthos to biocide applications?
         To other chemicals associated with plant operation?  Is
         reaction sufficient to threaten appreciable harm?
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     9.   Do macrozoobenthos accumulate toxic materials  for potential
         transfer to higher trophic levels?
    10.   Are there indications of gas-bubble disease in the dis-
         charge area?
    11.   If changes have occurred in the macrozoobenthic community
         what mechanism or combination was responsible?  Pump-
         entrainment?  Biocide reaction?  Reproductive  synchrony?
         Velocity?  Scour?  Substrate shifts?  Littoral drift
         shifts?  Food source?  Predation?  Parasitism?  Disease?
         Intermittent thermal excusions?  Chronic thermal
         conditions?

Off-site (Lakewide) Studies Related to Macrozoobenthos
     It should be noted that investigation of lakewide  effects
are not the responsibility of a single user, or group.   There are
many stresses on the waters of Lake Michigan and separation of those
caused by cooling water use is difficult.
     1.   What are the substrate types and their areal extent?
     2.   What are the habitat types and their extent?
     3.   What benthic fauna occupy these substrates and habitats?
         In what densities?  Community biomass?  Important species
         biomass?  Can these be generalized?
     4.   What roles do the benthic animals have in the  lake's
         ecosystem?
     5.   Which benthic animals are of primary importance to this
         system and why?
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     6.   To  what  extent would  elimination  (destruction)  of  a
         habitat  type  (or  portion  of  a  type)  and  its  associated
         biota  affect  the  lakewide ecosystem?
     7.   What  is  the effect, real  or  potential, of  local  effects  at
         one site  or all combined  local -effects on  the  lakewide
         ecosystem?
     8.   Can long-term chemical changes  in the lake have  an effect
         on  benthic animals and to what  extent will the  chemical
         additives from a  number of power plants  amplify  this effect?
     Major investigative  effort  should  be  directed  toward field
studies at present.   Clearly,  many of the  experimental  questions
posed are more research  than baseline surveys.   However, it should
be obvious to  the investigators  that  when  perturbations occur in
the field, the causative  factors  can  often  be isolated  only in
the laboratory.  Controlled  experiments and  research  needs  are
discussed later in this  chapter.

        Principal  Problem  Areas  In Understanding  Effects  of
                   Coojing Mater  Use  on  Benthos
     The problems associated with understanding  the results of
benthos investigations as  a  part  of  studies  of  cooling  water  use
fall  into four categories:  a) regulation  of benthos  abundance  and
community structure by natural environmental  factors, b) separation
of the effects due to  other  water uses  from  the  effects of  cooling
water use, c)  obtaining  precise  estimates  of abundance  and  communi-
ty structure,  and d)  demonstration of the  significance  of the
benthos in the over-all  lake ecosystem.
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Natural Environmental Factors
     From previous  investigations it seems reasonable to assume
that the off-shore  benthos community of Lake Michigan (exclusive of
Green Bay and many  near-shore areas) 1s essentially a single
community.  However, it has been found that abundance and community
structure of the benthos change with certain natural environmental
factors, chiefly depth and sediment composition.  Macrozoobenthos
abundance is usually very low at depths less than five meters and
increases with depth to a maximum at a depth of 30 to 60 meters.
At depths greater than 60 meters, benthos abundance decreases.  Near-
shore sediments with a high percentage of small particles and/or
a high organic content support large populations of tubificid worms
which are less abundant in other types of sediments.
     Normal turbulence due to wave action can move bottom sediments
                                                                     i
in areas shallower  than about 15 meters and redistribute the benthos
and small  particle  size material.  This material settles in depths
ranging from 15 to  60 meters with the heaviest deposition of organic
matter derived from the disturbed sediments occurring between
15 to 25 meters.
     Condenser cooling water intakes and discharges usually are
located in water less than 15 meters deep.  This is not the region
of maximum macrozoobenthos abundance but is the region in which
the abundance and composition of the benthos may change quite
significantly due to natural  factors:  depth, sediment composition,
and perhaps others.   These natural  variations in benthos compound
the problem of demonstrating effects of cooling water use,,
     Careful selection of areas for  sampling will  avoid this
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problem.   Test areas  in  which  cooling  water  use  effects  might be
observed  should be selected  with  adequate  consideration  of the
natural  effects of lake  currents  and wave  action.   Reference areas
should be selected to permit comparison  with the test areas in
depths,  sediment types,  and  as many  other  environmental  factors as
possible.
     The  benthic community  in  any given  area changes  seasonally
and annually.   Due to these  changes  comparison of  preoperational
data from a test area only  may not provide a very  clear  picture
of the effects of cooling water use.   Comparisons  of changes in
the benthic community of the test area with changes in the
reference area(s) provide the best approach for measuring effects.
Such comparisons will be of greatest value when preconstruction
and preoperational data  from test and  reference areas are avail-
able.
Effects of Other Discharges
     Discharges of waste materials to  Lake Michigan have caused
changes in the benthic community  in  some areas.   Some of these
changes are obvious and  highly localized such as the increased
abundance of leeches  and reduced  abundance of other benthos near
the discharge from a  steel  mill.   Some changes are more  widespread,
such as the increases in tubificid populations in  the 15 to 25 meter
depth range in association  with inputs of  organic  wastes at
several  points around the lake.  When  changes in the benthos in
areas of cooling water use  are found,  it must be determined whether
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the changes are due to cooling water use or to inputs of waste
materials.
     The best approach to this problem which can be suggested at
present is again careful selection of test and reference areas.
Particular attention should be given to distance from influential
discharges such as municipal wastewater treatment plants and
mouths of large rivers.  Selection also involves knowledge of pre-
vailing currents.  If both the reference and test areas are sub-
jected to the same environmental  influences except for the single
factor of cooling water use, the differences in changes between
the test and reference areas should be due to the cooling water use,
     Once a difference in the changes in benthos occurring in the
test area is found, this should provide verification for one of
the concerns expressed previously.  If it appears that one of the
mechanisms is actually operating in the lake, it should be further
tested by laboratory experiment.   Data from the laboratory experi-
ments, if properly designed and conducted, should be quite helpful
in separating the effects of cooling water use from the effects of
the input of waste materials.  Further information on the response
of benthos to various stresses should also be quite helpful for
sorting out effects.

Samp!ing Problems
     An objective of any program of benthos sampling is to obtain
samples giving a quantitative estimate of the abundance and species
composition of the benthic community or a representative fraction
thereofo  In any area the faunal  assemblage is likely to
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vary considerably from one sample to the next.   Thus replicate
samples are needed to estimate the mean and variability of indivi-
dual samples.  Samples from test and reference  areas must be
collected in a manner so that they provide comparable data.  Each
replicate sample in both areas should consist of organisms
collected over an equal  area and occupying an equal  volume of
sediment.  Since sampling devices are imperfect (i.e., any sampler
is somewhat selective) and do not collect equal volumes from
different sediment types, each sample should be examined immediately
after collection and rejected if the sampler does not contain an
appropriate volume or if there is evidence that the  sampler is
not functioning properly.
     Benthos tend to have different distributional patterns at
different depths.  While the expected distribution is random in
areas where sediments are disturbed by wave action and aggre-
gated in deeper areas, the benthos of some nearshore areas
may contradict this by exhibiting strong aggregation.  In cases
of animals with territorial  behavior (e.g., crayfish) the distri-
butional pattern may be  regular.   Statistical distributions which
may correspond to the various patterns of benthos  dispersion  are
Poisson for random, negative binomial for clumped, and positive
binomial for regular.  Sampling  an area to fully document patterns
of dispersion may require a  prohibitive number  of  samples.  For
statistical  treatment, mathematical  transformations  of the data
should be used only where there  is valid justification.   The normal
distribution should be assumed only when it can be shown that  the
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data fit.  When  the  data are inadequate either to demonstrate the
distribution  or  to  provide precise estimation of the parameters
of the distribution,  non-parametric procedures should be used, as
for data from different areas.
Determination of  the  Role of Benthos at Study Sites
     As previously indicated, the benthic community is of major
importance to the lake ecosystem as a source of fish food.  Since
it is important  to design a benthic sampling program which defines
                    (
the role of the  benthic community in the study area, stomach
contents of fish  of  a variety of species and ages should be
analyzed to determine the importance of benthic organisms in their
diet.  Such analysis  should be related to the seasonal benthos
communities.
                Objectives  Of  Measuring  Environmental
                      Conditions  and  Responses
     In general terms, the objectives of site-specific benthos
investigations are to quantify the on-site effects of cooling
water use, to establish the spatial  limits of benthic effects, to
determine the extent to which such effects are cause for concern,
and to relate measurable perturbations to the water body segment
or the Lake Michigan system as a whole.
     Some specific objectives of preconstruction  or preoperational
studies are establishment of the baseline environment for com-
parison with conditions during operation.   For comparison of
macrozoobenthos,the  bottom contours,  sediment types,  normal  seasonal
benthos abundance, distribution and  community structure should be
determined.  Knowledge of the important  species (e.g.  reproductive
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behavior and time, migration, thermal  tolerance)  and their role in
the system is highly desirable.
     Some specific objectives of operational  studies are to
determine changes in bottom contours,  sediment type and benthos
distribution, abundance, community structure  and  behavior (as
distinguished from normal  changes) caused by  construction and
operation of cooling water intake and  discharge.   If changes in
benthic populations are observed, the  question of the significance
of these changes to higher trophic levels should  be addressed.

                Benthic Study Field Methods

Col 1ection
     Benthic samples should be collected using appropriate and
recognized sampling devices and  methods.  The choice of sampler is
dictated in part by the substrate, depth, and organisms.  When
various techniques are employed  at one study  site,  a mechanism
should be adopted to compare techniques  on a  quantitative basis
after careful consideration.  There are  great differences in sampling
efficiencies among grabs.   In granular substrates the following
devices may be used:'

     1.  Grab samplers (Ponar, Petersen, Ekman, Smith-McIntyre)
     2.  Core samplers (single and multiple)
     3.  Sleds and dredge  nets
 For discussion  of relative  sampling  efficiencies  and  appropriate-
 ness see Powers and  Robertson,  1967;  Mozley  and Chapelsky,  1973;
 Beeton,  Carr and Hiltunen,  1965;  Flannagan,  1970,  and  Howmiller,
 1972.
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     In areas of rock outcrops, large rocks and gravel, or hard
packed clay, the following sampling devices may be used:
     1.  Pumps
     2.  Scuba divers (direct observation, in situ collecting, or
         photography)
     3.  Artificial substrates approximating natural substrates
     4.  Sleds
Separation
     Organisms should be separated from the sediment  by sieving or
elutriation or both.  Meshes should not be larger than those of a
U.S. Standard No. 30 sieve (589 microns).  Samples should be placed
in labeled containers and preserved with 10 percent buffered for-
malin or 70 percent ethanol.

     A U.S. Standard No. 60  sieve  (246 microns) may be used
when the substrate  allows.   This size is more efficient at re-
taining smaller  macroinvertebrates such as early  instar chironomids
and minute ol igochaetes.   Varying  sieve sizes affects comparabili-
ty  of the stations  and  the advantages of sieve sizes must be
considered against  the  effort of extracting and identifying these
small animals.   There is a possibility that samples of larger
animals from  a  larger surface area may be more valid statistically.
For more complete  community  estimates, two sample sizes and sieve
meshes might  be  used together.
     If organisms  are not  separated from the substrate in the
field, the entire  sample can be placed in a labeled container and
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kept cool and unpreserved until  it is separated,  preferably the
same day.  However, the organisms are subject to  predation and
also to death from anoxia or abrasion (followed by decomposition).
Since differences in numbers and sizes of animals recovered could
result from inconsistent methodology, trials  should be conducted
with known numbers of live animals to determine (a) the relation-
ship of holding time to percentage recovery and (b) the numbers
and sizes of animals recovered  by field separation techniques com-
pared with laboratory techniques.  It is preferable not to vary
collection and separation techniques  on a study area.
Sediments
     Although bedrock exposures  are found in  Lake Michigan, most
of the bottom is covered with  glacial deposits  overlain by more
recent sedimentary materials.   Descriptions are provided by Hough,
1935; Ayers and Hough,  1965; Ayers, 1967; Powers  and  Robertson,
1968; Somers and Josephson, 1968; and Mozley and  Alley, 1973.
These sediments play an important role in abundance and composi-
tion of the benthos since they provide the physical habitat for
all and the food supply for many.  Variations in  the  benthic
community with sediment type and composition must be  known in
detail before it is possible to ascertain the effects of other
environmental variables (such as temperature).   Some  of the
possible effects of cooling water use upon the  Lake Michigan
ecosystem are related to possible changes in the  sediment such as
the patterns of sediment erosion and  deposition near  discharges,
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or increased organic content in the sediments due to "fall-out"
of plankton killed during condenser passage.
Mapping of Sediments
     Sediments in the areas of actual  or potential  cooling  water
use should be mapped for selection of  sampling sites for field
studies of the benthic community and for estimating potential
effects on the habitat.  Five methods  used for sediment mapping
are applicable to benthos work:  grab  samples, core samples,  use
of divers, underwater television or photography,  and seismic
profi1es.
     1.  Grab samples are useful since the surface  layer in-
         habitated by most of the benthos makes up  a large
         portion of the sample.  However, the layered  character-
         istics are often disturbed by the action of the grab.
         When grab sampling an area of approximately 500 cm^,  the
         volume of each sample should  be at least one-half  liter
         to assure adequate representation.  If this amount cannot
         be collected by a single grab, a core sampler should
         be used.  However, in well-sorted, fine sand some  grabs
         are inefficient and core samplers do not retain the
         sample.
     2.  Core samplers penetrate deeper, but usually cover  less
         surface area than grabs.  They collect a smaller amount
         per sample of the critical upper layer mainly inhabited
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    by benthos,  but the  sample  Is  relatively undisturbed.
    Core samplers  are particularly useful  In areas  of hard
    clay where a grab will  not  penetrate to collect an
    adequate sample.   Examination  of the •edlment from a core
    sampler may  be confined to  the upper 2 cm for surfldal
    sediment mapping, although  the deeper sediments may be
    important to certain benthic animals.
3.   Divers trained in scientific observation and using
    techniques for random or design sampling can be useful
    in mapping sediment  characteristics.  Divers are
    especially valuable  for locating such features  as rock
    outcrops, patches of silty  or  organic sediments, or   i
    areas of macrophyte  growth  missed by other sampling   i
    techniques.
4.   Underwater television or photography are alternatives  to
    the visual observations supplied by divers.
5.   Seismic profiles  provide data  on gross distribution of
    sediments over large areas  but cannot provide the detailed
    information  on the upper layer of sediment over a small
    area needed  for evaluation  of  benthic habitats.  Sediment
    profiles  based on seismic data and some core samples are
    available from the Illinois Geological Survey for the
    entire southern basin of Lake Michigan.
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     Sediment mapping should extend at least 2 kilometers along
the shore in either direction from the point of discharge and at
least 2 kilometers away from shore.  These distances vary with
the site and size of the anticipated area of influence.  For
initial mapping, at least 10 samples should be collected over each
km2.  These could be supplemented by visual surveys by trained
divers to identify significant features of the bottom which may
be missed by random sampling.  Sediment mapping should also be
involved in selection of reference areas to insure comparability.
Laboratory Analysis of Sediment
     Sediment type is identified by laboratory analysis.  Since
there is no way at present to relate sediment mineralogy to
benthic communities, mineralogical analyses are not recommended.
However, it is highly important to have information on organic
content and the particle size distribution.  See Substrate Section,
page 188, for comments on quality of sediments.
     1.  Organic content should be measured by total organic
         carbon determination (TOC) and reported as percent dry
         weight (+_ 1 percent).
     2.  The particle size distribution of dry sediment should be
         determined by shaking it through a series of 7 sieves
         with the following separation sizes (Inman, 1952):
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Separation
size (mm)
2.00
1.00
0.5
0.25
0.125
0.0625
0.0039
Phi
(-Iog2d)
-1 .0
0.0
1.0
2.0
3.0
4.0
8.0
                                                      Class
                                             very coarse sand
                                             coarse sand
                                             medium sand
                                             fine sand
                                             very fine sand
                                             silt
                                             clay
     The Phi number (-log2 diameter in mm)  of the mean particle
     size and the standard deviation in Phi  values should be
     reported.   It is  also useful  to report  the percent (by
     weight) of particles less  than 0.0625  mm in diameter.
Sediment Chemistry
     Sediment chemistry of particular interest in evaluating
cooling water use describes the exchange of  materials  between the
sediments and water of the lake.   Specific  elements often are,  or
become, insoluble and  are deposited in the  sediments.   If toxic,
and biologically available, they  may reach  concentrations high
enough to alter composition of  the benthic  community.   It is also
significant that benthic organisms sometimes recycle nutrients
and other materials from the sediments into  the water  and back
into other trophic levels.
     Where cooling towers are used, evaporation increases chemical
concentrations  in the  blowdown.   Toxic materials may be used in
cooling tower maintenance.  Therefore, materials in blowdown
discharged into the lake have potential  for  accumulating in sedi-
ments over a relatively small area.  In view of the wide range  of

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blowdown contaminants, it is not possible to make general recom-
mendations on the types of analyses which should be performed,
however, investigators should be alert to the possibility that
changes in benthic communities may be due to changes in sediment
chemistry.
    Corrosion or erosion in circulating water systems may contri-
bute toxic metals to once-through cooling water discharges or to
cooling tower blowdown.  Metals of concern include copper, zinc,
and chromium.  Concentrations of these materials in the discharge
and physical models of their distribution over the receiving
area are needed before it is possible to specify the analyses
and precision.
Supporting Information
    The following information should be collected (concurrently,
and with appropriate periodicity) to assist in interpretation of
benthic ecological patterns which may emerge from the survey:
    1 .   Water Chemi stry
        a.  dissolved oxygen immediately above or in sediments
        b.  suspended organic matter
        c.  C:P:N ratio
    2.   Water depth (in meters)
    3.   Date and standard time
    4.   Temperature (Celsius) of bottom waters.  The relationship
        to overlying temperatures may be of value, as would be
        the temperature at the sediment-water interface or in
        the sediments at critical sites.  If the area of the
        bottom impacted by increased temperatures and the frequency
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        and amplitude of such increase  is  not well  known,
        interpretation of direct thermal  effects  will  be
        difficult at best.
    5.  Transparency, by photometer or  Secchi disc
    6.  Visual  examination  and description of the sediment at
        the time of sampling.  The sediment type  or combination
        of layered sediments may be encoded by a  single number
        or combination of numbers.  Example:   medium sand
        layered over hard clay - 10,  2/6,  or  silty  fine sand  =
        5, 4/3.
           1  -  Coarse sand                7 -  Clay-soft
           2  -  Medium sand                8 -  Gravel
           3  -  Fine sand                 9 -  Rock
           4  -  Silt                     10 -  Layered sediments
           5  -  Mixed                    11 -  Gelatinous
           6  -  Clay-hard
Sampling Design
    A statistician familiar with environmental  sampling should
be consulted  during the design stages of  the  program.
    Establishing Stations
    Sampling  stations in the test and reference areas  should  be
established in  a similar manner, either in a  grid system or by
random selection along transects.   The  number of  stations  and
number of replicate samples depends on  the degree of variability
in the habitats.  To determine the extent  and detail  of the pro-
gram, preliminary sampling  should be  done  to  evaluate  variability
in depths, sediments, water quality and benthos.   For  statistical
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 analysis  of  areal  differences,  stations  from  similar  habitats may
 be  grouped.
     Fixed Grid
     Areal extent  of  the  grid  and  proximity  of the  stations should
 fit  the size  and  the expected area of  influence.   The grid should
 be  modified  to  account for  special situations  as outlined below.
     Selection of  Reference  Area(s)
     The reference  area(s) should  be sufficiently remote from the
 test area to  be unaffected  by the plant  operation.  They should be
 as  similar as possible to the test area  in  topography, sediment
 types, distribution  of sediments, and water quality.  Differences
 will create  difficulties in interpretation  of  results and identi-
 fication of  changes  in the  test area.  Considerable effort
 should be expended in making as careful  and knowledgeable choice
 as  possible.  (See Principal Problem Areas  in  Understanding
 Effects of Cooling Water Use on Benthos, page  201.)
     Station  Identification
    Stations  should  be located with precision  and either marked
 by a buoy or  located  using  a transit with fixed shore points  or
 distance measuring equipment.   Far field or open lake stations
 can be accurately established  and relocated with ships'  radar
 and other navigational aids.
     Station  Distribution and Spatial  Interval
    Stations should  be distributed so results of sampling can be
 related to the frequency of occurrence of the discharge  plume
 in the test area.   Spatial  interval  depends upon the extent  and
 homogeneity of the area over which the target effects are to  be
evaluated.  Establishment of stations in the area where  heated
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water will contact the bottom 1s Important.   Additional  stations,
if necessary, should be located to measure and evaluate:   1)
erosion by disturbance of bottom sediments;  2) winter sinking
plume; 3) areas of increased fish predation; 4) areas of  "fall-out"
of organisms killed by condenser passage.   Additional sampling
sites may be needed to document special  situations.
     Sampling Frequency
     Ideally, sampling should be done every other month (six  times
per year) for the calendar year and more often during periods of
rapid change such as late spring or summer at a critical  site.
Minimum sampling frequency should be four times per  year,
seasonal.
     Number of Samples
     The number of replicates collected  at each sample site in
the test and reference area on each sampling date should  be
adequate for statistical  treatment as discussed in the Date Require-
ment Section (page 47) and Sampling Problems, page 204.  Generally,
at least three replicates should be collected each time and at
least four replicates may be required if non-parametric statistical
tests are used.  The number of replicates required may be much, much
greater than three or four if it is desirable to detect significant
differences in species abundance in the  presence of  the variability
usually found in benthic  populations.  A key to the  amount of
benthos sampling and detail desirable is associated  with  the
severity of impact experienced at the site and importance of  the
site specific and water body segment of  the benthic  community.
                             217

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    An approach to detect differences in abundance which is not
generally satisfactory is to assume that the Poisson distribution
(random distribution) model can be used to describe the data.
The square root transformation is used to "stabilize the
variance" and analysis of variance is applied to the transformed
data.
    There are good biological reasons to believe that benthic
population data should fit distributional models other than the
Poisson, such as the binomial or negative binomial.  If the
incorrect distributional model is used, then the incorrect data
transformation is used and analysis of variance will be less
likely to detect differences.  However, the number of replicates
required to examine detailed distributional properties of the
data may be beyond the resources of any particular study group.
    There should be a special study to determine the appropriate
distributional models for analysis of benthos data.  Until  such
a study is carried out, non-parametric tests are recommended.
When data distributions are not known, non-parametric tests often
have greater sensitivity to detect differences than analysis of
variance.  Design of sampling should be decided with the advice
of a statistician.
    Laboratory Techniques
    Sorting, identification and enumeration of benthic samples
should be performed using standard laboratory equipment, pro-
cedures, and techniques.  All identifications should be performed
with appropriate magnifiers and microscopes using recognized
taxonomic keys or publications.
                             218

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Data Presentation
    Generic and Specific I-denti fication
    In general, dominant organisms  should  be  identified to
species if possible and all other organisms should  be  identified
at least to genus, counted and quantified  in  units/m^.   Fol^owin-g
-t-hi.s-g=u-i del-4-ne-, -my si ds , decapods, amphipoxls ,  aird  mo:st_-o3-jg*DŁiHffiabes
s^hor3'd~~be -i-denti f.i-ed to species.  Sphaeri i dae s-ho u W-"fce-H d-e=n
-------
and Whipple (1959) is useful for other forms.
    Since use of the recommended sieve mesh size (589 microns)
will probably result in escape of the majority of Nematoda,
Ostracoda, Harpacticoidea, Platyhelminthes and benthic Cladocera,
identifying representatives of these groups to specific levels is
of little quantitative value.  Identification becomes important
when refined collection and separation techniques are used and
greater community description is desired.
    Biomass
    1.   Dry weight determinations should be made on unpreserved
        organisms since preservatives cause weight loss (Howmiller,
        1972b).   Organisms should be oven dried at 60C  for 24
        hours and weighed.
    2.   For ash free determinations, dried organisms should be
        placed in a muffle furnace at 600C  for 30 minutes.
        Ash free weight equals oven dry weight less final  weight
        after ashi ng.
    Diversity  Indices
    Depending on the level to which the organisms have been
identified, species diversity analysis may be conducted.   The
usefulness of species  diversity indices with Lake Michigan
zoobenthos is questionable (See Mozley, 1973).  Species "richness"
and "evenness" are of interest, but sampling and taxonomic problems
severely limit their use.   They are an optional means of
presenting data, if justifiable.
                             220

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             Research Needs and Controlled Experiments
    Although this  chapter focuses  on a very practical  field
problem, the evaluation  of the effects of cooling water use  on
Lake Michigan macrozoobenthos, solutions  to the mechanisms which
control  the undesirable  effects may  be most efficiently pro-
vided by basic research.   Field studies provide estimates  of
effect,  but often  do not  bear  on causative mechanisms.   While
no attempt will  be made  to provide an endless list of  laboratory
studies, carefully chosen laboratory research projects  can
provide  guidance for operational protocols that could  minimize
environmental impact.   It is  possible to  identify areas of
laboratory investigation  on benthic  organisms of immediate
practical  use.   One of the first questions concerns the simple
effect of heat on  the  benthos, that  is, temperature bioassays of
ecologically important benthic species to provide estimates  of
effects  of chronic and acute  exposure to  heat.
    Laboratory bioassays  have  been justifiably  criticized  for
the following reasons:
    1.  Such studies may  have  limited transfer  value.
    2.  Test conditions  in the laboratory may not adequately
        simulate simple  field  situations.
    3.  Bioassays  tend to treat a  single  factor at a time,
        making it  difficult to predict multiple effects,
        synergisms, or modifications that might occur  under
        natural  conditions.
    4.  More complex field situations are difficult and expensive
        to simulate in the laboratory.
    In view of the foregoing,  laboratory  studies should consider
                             221

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the following factors and their interactions:   temperature,
biocides, cooling tower blowdown products, dissolved gases.
    In general, the physiological  requirements of most species
of lake macrozoobenthos are poorly known, including even their
basic temperature and dissolved oxygen requirements.  Bioassay
and characterization of toxicity should characterize normal
requirements and develop criteria  to identify  responses to
changes from normal.  This knowledge is fundamental to under-
standing the results of environmental  change.   As a partial
remedy, the following steps are proposed:
    1.  Have competent specialists select key, dominant, or
        representative species, both site specific and water
        body segment specific;
    2.  Subject selected species to intensive  laboratory study
        to determine oxygen and temperature tolerances at
        various life history stages;
    3.  Standardize procedures, design variables, and reporting
        procedures for the testing; and
    4.  Perform toxicity and uptake tests for  biocides and
        heavy metals only on species for which oxygen and
        temperature tolerances have been developed.
    By standardizing bioassay protocols, information developed
for one site is more applicable to work related to other sites.
    The effect of intermittent heat or discontinuous generation
on benthic organisms is a second area  of concern which can be
profitably studied in the laboratory.   Irregular generation and
shifting plumes can cause unseasonal thermal  environments which
                             222

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may have significant ecological  effects  even though absolute
temperature differences  created  may be small.   Many physiological
and behavioral  activities,  such  as  reproduction and migration are
keyed to normal  seasonal  and daily  temperature patterns.
                  Priority  Needs and  Research
    Relatively  immobile  benthic  and sessile organisms may be
subject to continuous or  intermittent stress in the vicinity of
facilities using Lake Michigan  as  a source of  cooling water.
Stress may be caused by  discharge  velocity, thermal differences
or exposure to  chemicals  used in plant operation.   This may re-
sult in a difference in  benthic  communities in the vicinity of
such facilities  from those  remote  from the facility.
    Minimum stress to benthic organisms  is achieved by minimizing
the bottom area  exposed  to  harmful  conditions.  This may be
accomplished by  careful  discharge  location and design, and by
cooling water and wastewater treatment before  discharge.   Such
measures may entail  additional  use  of other resources and an
economic penalty to  the  discharger, which is ultimately passed
to the consumer.  Therefore, a  decision  should be  made on a case-
by-case basis as to  how  the benthos are  to be  protected.   The
bottom area in  the vicinity of  thermal discharges  may represent
a living space  denied to  benthic organisms and this space may
or may not be of significance to the biological community.
                             223

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    The need for biological judgment requires that this sub-
committee recommend some general and specific studies which
would compare the effect of environmental alteration to natural
situations.  Since some of these studies take precedent over others,
a system of priority has been established based on need, and
categorization has been accomplished based on the availability
state of the data, as follows:
    Priority - 1 - Highest priority consistent with achieving
                   primary goals of Panel;
               2 - High priority item directly supporting
                   priority 1 items;
               3 - Intermediate priority.
    Category - 1 - Solution available from existing data;
               2 - Solution available from ongoing studies;
               3 - Solution requires additional research.
     (A)  The discussion introducing this section identifies high
priority need for biological  information applicable to the
regulation and/or modification of thermal discharges:  determi-
nation of the importance of macrozoobenthos in the vicinity of
the discharge to the biological community of the receiving system.
The most obvious approach is  through field food chain studies on
site to aid in answering the  question of whether elimination or
alteration of macrozoobenthos in areas of varying size would
affect fish or their populations.
                            224

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Priority 1, Category 3.
    (B)  The second high priority information need is the
ability to distinguish the effects of cooling water use on
macrozoobenthos from contemporaneous changes  due to other causes
Priority 1, Categories 1 and 2.
    (C)  Because cooling water use represents only one of a
number of stresses on the Lake Michigan ecosystem and because
the macrozoobenthos of the vast profundal  and sublittoral areas
are of established importance to the biological  community, base-
line measurements of lakewide zoobenthos populations are needed
in sufficient detail that trends may be recognized at an early
date.   These base!ine measurements should  be  accompanied by a
seasonal biological map incorporating activities of important
species.
Priority 1, Categories 1, 2 and 3.
    To provide the above three information needs, other studies
and activities of a supportive nature should  be  initiated.
    (D)  Macrozoobenthos species lists with synonyms and known
        spatial and geographic distribution.
Priority 2, Category 1 and 2.
    (E)  Determine and list species of special significance and
specify reasons for significance, i.e.:
    a.  Benthic environmental quality indicators
    b.  Energy transfer in food chains
    c.  Recycling of nutrients, toxins and radioactive materials
    d.  Accumulators of materials of concern  (metals, organics,
        and radioactivity)
                             225

-------
    e.  Nuisance producers
Priority 2, Category 1 and 2.
    (F)  Determine sampling design and sampling devices necessary
to ensure minimum capability for identification of change.
Intensive review of exiting data should yield conclusions on
such factors as:
    a.  Replication and limits of statistical error
    b.  Spatial distribution of sampling efforts
    c.  Criteria to establish reference locations
    d.  Seasonal distribution of sampling effort
    e.  Data reporting criteria and format
    f.  Sampling devices
Priority 2, Categories 1 and 2.
    (G)  Identification of the degree of influence on benthic
populations by such factors as:
    a.  Chemicals (algacides, cleaning agents, chlorine blow-
        down products)
    b.  Thermal effects (intermittent, acute and chronic ex-
        posures, sinking plumes)
    c.  Riprap
    d.  Fish predation
    e.  Scour and velocity
    f.  Enrichment (organism "fall-out" from plumes)
Priority 1, Categories 1, 2 and 3.
    Items D, E, and F above relate to the basic problem of  benthos
investigation on any body of water on which several academic,
enforcement, industry, and consultive entities are working:
non-uniformity of methods.  This leads to a low degree of data
                             226

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comparability.   Utility of results and efficiency of the total
effort would be increased greatly by adopting compatible,
if not uniform, methods.   Therefore, a recommendation is made
for two workshops:   the first on taxonomy and nomenclature and
the second on sampling and data analysis.  No priority has been
established, but these workshops are considered highly signifi-
cant to an orderly assessment of thermal  effects on the macrozoo-
benthos of Lake Michigan.
                              227

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    13: 703-705.

Wells, L. and  A.  M.  Beeton.  1963.   Food of the  bloater,
    Coregonush oy_i, in Lake  Michigan.   Trans. Amer. Fish. Soc.
    92(3): 245-255.
                        Smithsonian  Series


Burch, J.B.  1972.   Freshwater  sphaeriacean  clams  (Mollusca:
    Pelecypoda)  of North America.   Biota  of freshwater  ecosystems
    identification manual  no.  3.   U.S.  EPA  18050  ELD.

Ferris, V.R.,  J.M. Ferris  and  J.P.  Tjepkema.   1973.   Genera  of
    freshwater nematodes (Nematoda)  of  eastern North  America.
    Biota of freshwater ecosystems  identification manual  no.  10
    U.S. EPA 18050 ELD.
                               233

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Foster, N. 1972.  Freshwater po?ychaetes (Annelida) of North
    America.  Biota of freshwater ecosystems identification
    manual no. 4.  U.S. EPA 18050 ELD.

Hobbs, H. H., Jr. 1972.  Crayfishes (Astacidae) of north and
    middle America.  Biota of freshwater ecosystems identification
    manual no. 9.  U.S. EPA 18050 ELD.

Holsinger, J. R. 1972.  The freshwater amphipod crustaceans
    (Gammaridae) of North America.  Biota of freshwater ecosystems
    identification manual no. 5.  U.S. EPA 18050 ELD.

Kenk, R. 1972.  Freshwater planarlans (Turbel laria) of North
    America.  Biota of freshwater ecosystems identification
    manual no. 1.  U.S. EPA 18050 ELD.

Klemm, D. J. 1972.  Freshwater leeches (Annelida:Hirudinea) of
    North America.  Biota of freshwater ecosystems identification
    manual no. 8.  U.S. EPA 18050 ELD.

Williams, W. D. 1972.  Freshwater isopods (Asellidae)  of North
    America.  Biota of freshwater ecosystems identification
    manual no. 7.  U.S. EPA 18050 ELD.
                             234

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                   SECTION  VII



MEASUREMENT OF THE EFFECTS  OF  COOLING  WATER  USE



                  ON THE FISHERY

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Section VII,  MEASUREMENT QF JHE EppECTS pp COOLING WATER USE
                            ON THE FISHERY
                          Table of Contents

Introduction.     .........    .238
       Historical Description of Great Lakes
            Fish  Stocks     .......    .238
       Utilization by Man   .	242
       Effects of Pollution and the Electric Power
       Generating Industry  on F1sh Stocks  ....    .244
Principal Problem Areas     .    .     .     .    .          .    .247
Program for Measurement of  Effects   .     .    .    .     .    .254
       Introduction and Research Priorities    .    .     .    .254
               Priorities	255
               Categories   .......    .255
       Quantifying Statement on Program Orientation .     .    .256
Methods of  Investigation    .......    .258
Before and After  Studies    .......    .258
       Questions  to be Answered ......    .258
       Materials  and Methods    ......    .260
               Trawl Sampling of Juvenile  and Adult Fish  .    -260
               Gill net Sampling of Juvenile and Adult Fish    .266
               Seine Sampling for Juvenile and Adult Fish.    .269
               Plankton Net Sampling for Fish Fry   .     .    .271
               Pump Sampling of Fish Eggs  ....    .272
               Tagging or Marking of F1sh  ....    .273
Intensive Plume  Studies     .......    -276
                               236

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                          Table  of Contents

       Questions  to  be  Answered  .    .    .  .  .    .    .    .    .    -?77
       Materials  and Methods     	
  On-s1te Bloassays  .
       Questions  to  be  Answered	287
       Materials  and Methods	288
  Laboratory Studies	289
       Questions  to  be  Answered	289
       Materials  and Methods	290
  Lakewlde Studies	292
       Questions  to  be  Answered	293
       Materials  and Methods	294
            Trawl  Sampling of Juvenile and Adult F1sh    .    .    .294
            6111 net Sampling  of  Juvenile and Adult F1sh .    .    -295
            Seine  Sampling for Juvenile and  Adult  F1sh  .    .    -295
            Plankton Net Hauls for F1sh Fry  Assessment  .    .    .295
            Pump  Sampling of  F1sh  Eggs	297
Literature Cited      	298
                            237

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        SECTION VII MEASUREMENT OF THE EFFECTS OF
             COOLING WATER USE ON THE FISHERY

                       Introduction

Historical Description of Great Lakes Fish Stocks
     The Great Lakes and their tributaries and connecting waters
contain an extensive fish fauna which includes representatives
of most of the important families of North American freshwater
fishes.  Hubbs and Lagler (1958) described 20 families and 173
species in the Great Lakes drainage basin and stated that
theirs was undoubtedly an incomplete list.  Although nearly all
of the fish native to the drainage basin had access to Lake
Michigan, relatively few species became established in the Lake
proper, and most of these  were cold water species.
     A complete list of the fish fauna of Lake Michigan is not
available, but according to Wells and McLain (1973), a number of
of species were, or are now common (Table VII-1).
     The fish fauna of Lake Michigan, as the early settlers
found it, was dominated by salmonids of which the whitefish,
lake herring, and lake trout were the most abundant.  Since that
time, several species of coregonines have become rare or have
disappeared from the Lake.  The lake sturgeon is now rare, the
native lake trout population was exterminated and the Michigan
grayling, apparently an anadromous species, is now extinct
(See Wells and McLain, 1973 for a detailed description of these
and other changes in the fish stocks of the Lake).
                           238

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Table VII - 1.  Fish fauna previously or currently common
                to Lake Michigan.1
COMMON NAME
SCIENTIFIC NAME
Sea lamprey2
Lake sturgeon
Alewife2
Lake whitefish
Blackfin cisco
Deepwater cisco
Longjaw cisco
Shortjaw cisco
Bloater
Kiyi
Shortnose cisco
Lake herring
Round whitefish
Lake trout
Brook trout
Rainbow trout (steelhead)2
Brown trout2
Coho salmon2
Chinook salmon2
Petromyzon marinus
Acipenser fulvescens
Alosa pseudoharengus
Coregonus clupeaformis
Coregonus nigripinnis
Coregonus johannae
Coregonus alpenae
Coregonus zenithicus
Coregonus hoyi
Coregonus kiyi
Coregonus reighardi
Coregonus artedi i
Prosopium cylindraceum
Salvelinus namaycush
Salvelinus fonti nali s
Salmo gairdneri
Salmo trutta
Oncorhynchus kisutch
Oncorhynchus tshawytscha
1
 According to Wells and McLain (1973).
2Species that have gained access to the lake and have become
 abundant during the period of historical  record.
                       239

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Table VII - 1 Continued.
Rainbow smelt2
Northern pike
Carp
Emerald shiner
Spottail shiner
Longnose sucker
White sucker
Channel catfish
Bullheads
Trout-perch
Burbot
Ninespine stickleback
Smallmouth bass
Yellow perch
Waileye
Freshwater drum
Slimy sculpin
Spoonhead sculpin
Fourhorn sculpin
Osmerus mordax
Esox 1u c i u s
Cyprinus carpio
Notropis atherinoides
Notropis hudsonius
Catostomus catostomus
Catostomus commersoni
Ictalurus punctatus
Ictalurus spp.
Percopsis omiscomaycus
Lota 1ota
Pungitius pungitius
Micropterus dolomieui
Perca flavescens
Stizostedion vitreum vitreum
Aplodi notus  grunniens
Cottus  cognatus
Cottus  ricei
Myoxocephalus quadricornis
2Species that have gained access to the lake and have become
 abundant or common during the period of historical record.
                        240

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     While many of the native  fishes  of the  Lake  were  declining
in abundance,  several  exotic  species  became  established and
reached high levels of abundance.   In some  instances,  these
exotic species caused  or hastened  the decline  of  native stocks
by preying on  them or  competing  with  them for  food  or  space.
The carp was one of the earliest deliberate  introductions  to
the Great Lakes basin.  It  is  mainly  a fish  of the  tributaries
and the shallow inshore waters and its effect  on  the  native fish
populations of the Lake, although  probably  detrimental, has not
been adequately measured.   The rainbow smelt,  another  deliberate
introduction,  has become a  food, sport and  forage fish; however,
it is also credited speculatively  with causing major  declines  in
the lake herring population.   The  sea lamprey, a  marine species
that apparently migrated into  the  Great Lakes  through  man-made
canals in the  1800's,  became  abundant in Lake  Michigan in  the
middle 1940's.  This species  was largely responsible  for the
decline in abundance of a  number of desirable  native  species  and
the extinction of the  native  lake  trout and  several  species of
large coregonines.  The alewife, a marine invader,  was first
seen in moderate numbers in the  Lake  in the  middle  1950's  after
the lamprey had eliminated  the  larger  predators.   The  alewife
reached peak abundance in  the  fall of 1966,  but  following  a
massive die-off that occurred  in 1967, the  population   seems  to
have stabilized at a substantilly  lower level  of  abundance.  The
alewife competes for food  with many native  species  and has
apparently caused major changes  in the zooplankton  composition
                            241

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of the Lake (Wells, 1970).  The alewife is also the most
important food item in the diet of trout and salmon in Lake
Michigan.
     Control of the sea lamprey and the relatively stringent
restrictions placed on the commercial  fishery in Lake Michigan
since the late 1960's have permitted the recovery of various
lake spawning species including the whitefish.   Control  of the
sea lamprey and the presence of a large forage  stock of  alewives
set the stage for the rehabilitation of the lake trout and
other anadromous stocks of trout in the Lake.  Coho and chinook
salmon were successfully introduced in 1966-1967 followed  by the
apparent successful establishment of the Atlantic salmon in the
Lake in 1972.

Utilization by Man
     A commercial fishery has existed  in Lake Michigan at  least
since 1843.  According to Wells and McLain (1973) the earliest
fishery was conducted for whitefish, which were abundant in the
inshore waters of the lake.  Total commercial fish production
for Lake Michigan in 1879 (the first year of record)  was nearly
24 million pounds, of which about half was whitefish.  Pro-
duction increased to about 41 million  pounds annually in 1893-
1908 due primarily to increases in the catch of lake herring.
Production fell to about 24 million pounds annually in 1911-1942,
     Total production averaged 26 million pounds annually  during
1943-1965, but the period was one of marked instability  and
                           242

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change in the fishery.   During  those years  the lake trout
disappeared from the commercial  catch.   Whitefish stocks de-
clined to very low levels  and  the species  virtually disappeared
from the catch for several  years.  The  catches of smelt and
walleye rose briefly to record  levels,  and  the alewife made
its first appearance as a  species of commercial  importance in
the lake.
     Total production averaged  about 51  million  pounds annually
in 1966-1970 and 46 million pounds annually in 1971-1973.  Of
the total production, alewives  averaged  42  million pounds
annually in 1966-1970 and  32 million pounds in 1971 -
1973.
     Because of the depleted condition  of  some fish stocks and
the need to reserve other  stocks for the rapidly growing sports
fishery, the future of the commercial fisheries  of Lake Michigan
can at best be called uncertain.
     Angler interest in Lake Michigan is now at  an all time high
because of the trout and salmon management  programs, and there
is every indication that this  interest  will continue to grow and
be a major determinant for management of the fish stocks of the
Lake.  Angler catches, which in the 1950's  and early 1960's
probably reached a record  low  for the Lake, began to climb with
the partial rehabilitation of  the lake  trout and steelhead
stocks, the establishment  of stocks of  lake-dwelling brown
trout, and the successful  introduction  of  Pacific salmon.  In
1972, the most recent year for which published records are
                           243

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available, the angler catch In the State of Michigan's waters
of Lake Michigan was 347,000 steelhead trout, 311,000 lake trout,
610,000 coho salmon, and 234,000 Chinook salmon (Michigan De-
partment of Natural Resources, 1973).  Few statistics are
available on the sport fishery for other species in the Lake,
but the once productive inshore (pier) fishery for yellow perch
is again attracting large numbers of anglers in some areas and
daily catches of up to 100 fish per angler are being reported.

Effects of pollution and the electric power generating industry
on fish stocks
     In the early days of settlement, untreated sewage and sawmill
wastes were problems in river and harbor mouths and adjacent
areas and the major effect on the fish populations of the-Lake
was probably felt by anadromous species.  Large pockets of heavy
pollution from municipal and industrial sources exist today.
The absence of desirable species and the lowered fishery pro-
ductivity in Southern Green Bay, for example^ can be attributed
to pollution.  Pollution of the entire Lake by DDT, mercury,
PCBS  and other conservative or long-lasting contaminants from
point and nonpoint sources is also a matter of great concern.
A number of species in the Lake have contaminant levels that
exceed safe levels set by the FDA for human consumption.

     Recently the effects of electric power generation on the
Great Lakes and their biota have come under scrutiny.  Serious
inquiry into these effects was initiated in the 1960's when it
                           244

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was recognized by resource agencies in the basin that future waste
heat discharges to the Lake might become large enough to pose
a threat to water quality and to the fisheries of the lakes.
Present concern over the adverse effects of once-through cooling
includes not only the effects of waste heat discharges on the
Lake and its biota but also losses that occur when fish and
other organisms are drawn into plant cooling systems.  The kinds
of damage that may occur to fish and other organisms as a result
of electric power generation at steam electric stations have
recently been summarized by Edsall and Yocom (1972) and by Clark
and Brownell (1973).

     An adequate and reliable demonstration of the effects of
electric power generation with once-through cooling on the fish
populations of Lake Michigan has not been made.   Utility company
records show that large numbers of fish are killed at plants now
operating with once-through cooling on Lake Michigan, but infor-
mation on the distribution,abundance,and dynamics of the fish
stocks of the Lake needed to assess the significance of these
measured mortalities at power plants is not yet available. Con-
sequently, the present basis for concern over the adverse effects
of existing power plants on the fishery productivity of the Lake
is partly conjectural.
          y
                                             -/
     Lack of an empirical assessment of the impact of cooling
water use at existing power plants on the fishery productivity
                                          \
  4
                          245

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of the lake makes 1t Impossible to accurately predict the con-
sequences of future increased use of the lake water for cooling.
Nevertheless, the available Information suggests that the elec-
tric power generating Industry will have a serious impact on the
fishery productivity of the Lake in the future unless alternatives
to open-cycle cooling are employed (Great Lakes Fisheries Lab,
et al.1970).  For example, withdrawals of cooling water and all
discharges of wasteheat by power generating plants on the shores
of Lake Michigan occur within the littoral area.  In Lake Michigan,
these littoral waters are equal in volume to only 0.4 percent of
the volume of the whole lake.  If projected power demands were met
only with plants using once-through cooling, the cooling water
withdrawals by the electric power industry on Lake Michigan in
the year 2000 would be about 91,000 cubic feet per second.  This
rate of withdrawal would require passing a volume equivalent to
one percent of the littoral water of the entire lake through the
cooling systems of power generating plants daily (Great Lakes
Fisheries Lab, et al»1970).  Because damage is probably proportion-
al to the cooling water use rate, extremely high mortalities of
fish in the littoral waters of Lake Michigan could be expected
if these waters were used for cooling at a rate of one percent
per day.

     Although the littoral waters of the lake are only a small
fraction of the total lake water,these littoral waters are vital
to the existence of almost every species of Great Lakes fish.
                              246

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Only the deep water sculpin and a  few species  of deep water chubs
are absent from the littoral  waters.   Fishes such as  yellow perch,
smallmouth bass, northern pike, and walleyes,  are all relatively
permanent residents of the littoral waters.   Other species such
as the lake trout and most of the  whitefishes..use the littoral
waters during the colder portion of the year as feeding and
spawning grounds and as nursery areas for their young.  Fishes
that spawn in tributaries of the lake must pass through the
littoral waters on their way to and from the spawning grounds
and their offspring must pass through these  waters when they
migrate to the Great Lakes for the rapid growth phase of their
lives.  Thus the littoral waters exert considerable influence on
the fishery productivity of the Great Lakes  and there is a great
need to provide protection for fish and their  food organisms in
this important area of the lake.

                    Principal Problem Areas
     Steam electric generating plants operating with  once-through
cooling create both intake and discharge "problem areas" for Lake
Michigan fish (see Edsall and Yocom 1972 for a review).  Although
the Fisheries Section of this panel report was restricted to con-
sideration of only the effects of  power plant  cooling system dis-
charges, it is necessary to present at least a general outline  of
both intake (Fig. VII - 1) and discharge (Fig. VII -  2) problem
areas because the intake and discharge problems at most plants  on
Lake Michigan are not clearly separated.  Many of the fish taken
                            247

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               Figure VII  -  1.    Principle  problem  areas  associated with  power plant  intakes.
                                                              FISH ENTER INTAKE
                         FISH TOO LARGE TO
                   PASS THROUGH TRAVELLING SCREEN
                                                                                    FISH SMALL ENOUGH TO PASS
                                                                                    THROUGH TRAVELLING SCREEN
                                                                                  AND ARE PASSED THROUGH PLANT
ro
4k
03
FISH KILLED IMMEDIATELY OR
ULTIMATELY BY IMPINGEMENT
      FISH REMOVED FROM
        FOREBAY ALIVE
      DISPOSAL
      ON LAND
                  DISPOSAL
                  IN LAKE
[FISH UNHARMED |   [SUBLETHAL EFFECTS
FISH RELEASED
 IN DISCHARGE
                        POSSIBLE ADVERSE
                          EFFECTS ON
                         WATER QUALITY
FISH RELEASED
IN DISCHARGE
t

FISH RETURNED
TO LAKE REMOTE
FROM DISCHARGE
1

FISH RELEASED
IN DISCHARGE
t

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                  Figure VII  -  2.    Principle  problem areas  associated with  power  plant  discharges.
10
                                             FISH EXPOSED TO DISCHARGE
                                                                                 FISH DRIFT INTO DISCHARGE
          FISH SWffl INTO DISCHARGE
                                                                                                           FISH CARRIED INTO
                                                                                                         DISCHARGE FOLLOWW8
                                                                                                            PLANT PASSAGE
                                               FISH ENTRAINED
                                               DIRECTLY FROM
                                               RECEIVING WATER
FISH UNHARMED
   NO FURTHER
EXPOSURE TO PLANT
                                          FISH ENTRAINED
                                                                                NO FURTHER
                                                                             EXPOSURE TO PLANT
                                                                                       FISH ENTRAINED
                                                                                         AT INTAKE
                                                                                        FISH NOT
                                                                                        EXPOSED
                                                                                         AGAIN

-------
in at the intake may pass into the discharge, and fish present in
the discharge may be drawn into the intake when the effluent is
accidentally or deliberately recirculated.

     Although recirculation is recognized as undesirable because
it may result in increased entrainment and impingement of fish,
the seriousness of the problem in Lake Michigan appears to be
virtually unknown.  However, it is clear that all  of the fish
large enough to be impinged on the traveling screens of existing
power plants on Lake Michigan a're killed when they are drawn into
these plants because none of these plants are now equipped with
devices that would permit returning these entrapped or impinged
fish to the lake alive and unharmed.

     The problem of the combined effects of plant passage and
subsequent exposure to adverse conditions in the discharge plume
is one that has received general recognition.  However, until the
level of mortality caused by plant passage alone is determined,
it is impossible to state whether the additional exposure obtained
in the discharge plume is important to these fish.  The available
information (see Coutant and Kedl 1975, Beck and Miller 1974,
Marcy 1973, 1974, and Clark and Browne!! 1973) suggests that
fish small enough to pass through the traveling screens will
probably experience high to very high mortality during passage
through the plant because of exposure to high lethal temperatures,
hydraulic or physical mauling (caused by the pumps and collision
with internal surfaces of the cooling system) and lethal  concen-
                               250

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trations of chlorine.

     A more thorough discussion  of intake problem areas  is  pre-
sented in Section  VIII  of  this report.

     Fish that are entrained  at  the discharge  and those  that sur-
vive passage through the  plant cooling  system  are exposed to
various conditions that may threaten their survival.   These
include:
     1)  hydraulic mauling, particularly  at plants  with  a high
         velocity  discharge (Clark and  Brownell  1973),
     2)  elevated  temperatures (Coutant and Kedl  1975, Clark and
         Brownell  1973, Edsall and Yocom  1972),
     3)  chlorination  (Basch  and Truchan  1973,  Stober and Hanson
         1974),
     4)  gas embolism  (Coutant and Kedl 1975),
     5)  predation:  those that  are incapacitated to  some extent,
         even temporarily, may have reduced ability to avoid
         predators and  have an increased  probability  of  being eaten
         by predators  concentrated in or  near  the plume  (Coutant,
         etaK 1974, Yocom and Edsall 1974, Coutant 1973, Hocult
         1973, Sylvester  1972, Gritz 1971), and
     6)  displacement:  discharge currents may  interfere  with move-
         ments of  young fishes and prevent them  from  reaching
         required  or favored  habitat (see Houde  and Forney  1970,
         Houde 1969b).
                                251

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     The discharge of heated water from a power plant will cause
marked changes in the distribution of fish in the vicinity of the
plant.  Most Lake Michigan species appear to be attracted toithe
heated discharge during a portion of the year and are absent from
or avoid the discharge during the rest of the year (Romberg and
Spigarelli 1973,Edsall and Yocom 1972).  Fish attracted to and
residing in a heated plume in Lake Michigan could be killed or
damaged in a number of ways.  For example:
     1)  fish encountering a sharp thermal gradient may be unable
         to respond and may be killed by high temperature (Gall-
         away and Strawn 1974, Meldrim and Gift 1971, Van Vliet
         1956),
     2)  fish acclimated to high discharge temperatures, especially
         in winter, die or are debilitated by cold shock if the
         plant heat output is interrupted (Coutant, eta!0 1974,
         Clark and Brownell 1973, Edsall and Yocom 1972),
     3)  high gas saturation of the discharge waters, especially
         in winter, may create conditions in which fish would be
         killed by gas bubble disease (Otto 1973, DeMont and Miller
         1971),
     4)  chlorination of the cooling water may kill fish, or drive
         them from the discharge area (Basch and Truchan 1973);
         those driven from the discharge in winter could suffer
         cold shock (see 2 above), or experience reduced repro-
         ductive success (Arthur and Eaton 1971),
     5)  fish residing at elevated discharge temperatures will
                           252

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     concentrate pollutants,  including  mercury  and  DDT,  more
     rapidly than  those  living  at  lower  temperatures  (Reinert,
     et al.1974, MacLeod  and  Pessah  1973),
 6)   toxicity of some  pollutants  is  higher  at higher  temper-
     atures  (Stober and  Hanson  1974,  MacLeod  and  Pessah  1973,
     Macek,  et al.1969,  de  Sylva, 1969).
 7)   the incidence  and lethality  of  various fish  diseases  may
     increase with  temperature  (Fryer and Pilcher 1974,  Plumb
     1973,  Ordal and Pacha  1963),
 8)   reproductive success of  yellow  perch and possibly
     other  species  may be reduced by exposure of  mature  adults
     to overwintering  temperatures  exceeding  those  found in
     nature  (Brungs 1971, Hubbs  and  Strawn  1957,  unpublished
     data,  National Water Quality Laboratory, Duluth,  Minn.).
 9)   reproduction times  may be  altered  significantly  (Adair
     and Demont 1970,  DeVlaming  1972),
10)   demersal eggs  spawned  in areas  with  even small  temperature
     increases (including those  areas impacted  by winter sinking
     plumes) may die (Powles  1974)  or will  have accelerated
     embryonic development  and  hatch early  (Colby and  Brooke
     1973,  Brooke unpublished MS, Berlin  eta!0  unpublished MS);
     the fry may be out  of  phase  with their planktonic food
     supply  and a larger  than normal  percentage may  be lost
     to starvation,
11)   during  the winter months,  fish  residing  in heated ef-
     fluentsmay lose weight because  their metabolism  will  be
     high and their food  supply  may  be  low  (Kelso 1972,  Brett
                       253

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         et al.1969, Marcy 1967),
    12)  migratory fishes may spend a great deal of time at
         various thermal discharges thereby altering migration
         patterns or schedules and substantially increasing their
         exposure to abnormal temperatures (Spigarelli and Thommes
         1973).

              Program for Measurement of Effects
Introduction and Research Priorities
     The research program is divided into five major subsections:
Before and After Studies, Intensive Plume Studies, On-site
Bioassays, Laboratory Studies, and Lakewide Assessment Studies.
The research activities described in these sections are complemen-
tary and are intended (collectively) to provide the basis for
measuring a portion of the effects of power plant discharges on
the fish of Lake Michigan.  (A complete description of the effects
of power plant operation on Lake Michigan fish and the assessment
of the biological significance of these effects requires that data
also be obtained on intake damage to fish and on intake and discharge
damage to the organisms that serve as food for these fish.)

     In each of the five sections we present a list of questions
that we believe should be answered for each cooling water use
site.   It may be possible to answer some of these questions
adequately with information that already exists in the literature
(for example, published information on the low temperature
tolerance of yellow perch suggests that the species would not be

                            254

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susceptible to cold shock death at Lake Michigan power plants)
or from information collected at nearby sites.   Questions that
cannot be-adequately answered with existing information define
the research needs for that site.   These questions are grouped
and assigned numerical priority rankings to reflect a logical
order for programming research efforts.  Some reordering may be
necessary when these guidelines are put into practice at a par-
ticular site because these priorities must be to some extent site
specific.

     Definitions of numerical rankings are as follows:
     Priorities
     1 - Highest priority consistent with achieving the primary
         LMCWSP goal of determining the effect of cooling water
         use on the Lake Michigan  ecosystem.
     2 - High priority item directly supporting priority 1 items.
     3 - Intermediate priority item generally supporting priority
         2 items.
     Categories
     1 - Questions which are answerable with currently available
         data; additional research is not needed.
     2 - Questions which may be answerable with data currently
         available.
     3 - Questions which are not answerable with currently avail-
         able data; additional research is needed.
                           255

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Qualifying Statement on Program Orientation
     This section of the report provides specific methodologies
for use as guidelines in the demonstration of the possible adverse
effects of once-through cooling on the fish populations of
Lake Michigan.  Because of the specific nature of these recommen-
dations, it is appropriate to preface them with some qualifying
remarks.

     Answers to many of the questions posed in the following
sections of this subcommittee report can be best obtained through
the use of conventional time-tested sampling gear and methods
that are of universal acceptance among professionals and resource
agencies with long histories of experience with the Lake Michigan
fishery.  Adoption by the electric power generating industry of
these methods and types of sampling gear recommended in the guidelines
will provide continuity of record and permit direct comparison of
fishery data with data collected over the past several  decades by
fishery resource agencies.
     Despite the need for standardization of gears and  methodologies,
differences among sites and differences in the design,  capacity,
and operating characteristics of the power generating plants on the
Lake, may make it impossible to carry out identical fishery sampling
procedures at all sites.  Studies initiated before these guidelines
were developed may not conform to these guidelines, but data
from these studies may prove to be adequate for the evaluation
of certain local effects at the study site.  It is also
                             256

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clear that methodologies needed to answer some of the questions
posed in the following text (see for example the section dealing
with Intensive Plume Studies)  have not been developed and consid-
erable latitude in approach toward answering these questions is
desirable and necessary.  Deviations from prescribed procedures
and criteria of performance, however, should not be made without
clear justification, nor should they be made in a manner that
prevents acquisition of data directly comparable and equivalent
to data that would be obtainable following the methodologies set
forth herein.
     The level of field sampling effort required to reliably
describe fish stocks will vary greatly among species and life
stages of each species, and it is virtually impossible to specify
the level of effort required at a given site without knowledge of
the kinds and numbers of fish  found on the site and the uses they
make of the site.  Generally,  the level of field sampling effort
expended to answer the questions posed in the methods section of
this report should at least be high enough to permit detection of
true minimum differences of 20 percent at the 5 percent probability
level.  The amount of field sampling effort specified herein may
require adjustment to achieve  this degree of sampling precision.
                            257

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Methods of Investigation
     Before and after studies
     This section describes methodology to determine the size
and composition of the fish stocks at the study site before plant
operations begin and following the onset of plant operation,
and to determine the uses fish make of the site and the extent to
which these uses are altered by plant operation.  The recommended
period of study is at least three years prior to, and three years
subsequent to full plant operation.  The sampling grid (Figure VII  -  3)
is scaled for use at a site occupied by a plant with a cooling water
use rate of 3,000 - 4,000 cfs and a temperature rise across the
condenser of approximately 11C.

     A rescaling of this grid and a change in the effort would be
necessary at sites where the amount of cooling water used or  the
amount of waste heat rejected was markedly different.

          Questions to be Answered
     1.  What kinds and numbers of fish are found in the vicinity
of the plant site and how does this change diurnally, seasonally,
annually, and as a result of plant operation? (Priority 1,  Category 2)
     a.  what is the age, size, and sex composition of these
         populations and how does it change diurnally, seasonally,
         annually, and as a result of plant operation?  (Priority 2,
         Category 2)
     b.  what use is made of the site as a spawning, nursery,
         feeding or over-wintering ground or as a migration route
                              258

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                                                                  (36.4m)
ro
(Jl
                                                                                          Depth Contour
                                                       Discharge on Centerline
              Figure  VII - 3.   Suggested  sampling  stations for  fisheries  investigations
                                 of Lake Michigan.

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     by fish, and does this change as a result of plant
     operation? (Priority 1, Category 2)
 q.  what are the age-specific food habits of each species
     in the vicinity of the site and how do they change
     seasonally and annually, and do these change as a result
     of plant operation? (Priority 2, Category 2)

      Materials and Methods
Trawl sampling of juvenile and adult fish
a.   Sampling Location - All stations shown in Figure VII  - 3.
b.   Gear
    1)  Sixteen-foot semiballoon bottom trawl for stations
        0-10 feet; 16-ft headrope, 19-ft footrope (actual
        spread approximately 12 ft), net made of nylon
        netting of the following size mesh and thread;
        1-1/2" stretched measure No. 9 thread body, 1-1/4"
        stretched measure No. 15 thread cod end, 1/2"  stretched
        measure No.  63 thread knotless nylon inner!iner, head
        and foot ropes of 3/8" diameter Poly-dac net rope
        with legs extended 3 ft and wire rope thimbles spliced
        in at each end with shackles attached to fasten net
        onto doors.   Six 1-1/2" x 2-1/2" Ark floats spaced
        evenly on center of headrope.  1/8" galvanized chain
        hung loop style on footrope.  Net treated in green
        copper net preservative.  Trawl is available from
        Marinovich Trawl Co., Inc., 1317 East First Street,
                        260

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        Biloxi, Miss.  39533*.
    2)  Thirty-nine foot bottom trawl  for all  other stations
        in Figure VII  - 3:  3/4 size Yankee standard No. 35.
        Headropes, 39  ft;  sweep,  51 ft;  wings  and squares,
        3-1/2 inch stretched,  21  thread  nylon; belly, 2-1/2
        inch stretched, 21  thread nylon; cod end 1/2 inch
        stretched nylon seine  netting, 12 ft in length.
        Trawls are available from Gloucester Grocery and Boat
        Supply Co., Inc.,  17-21 Rogers Street, Gloucester,
        Mass. 01930*.                                             ;.
c.  Sampling frequency
    1)  Collect at all stations monthly.
    2)  Make duplicate 10-minute  trawl tows on the bottom
        parallel  to the bottom contour at each station.  Make
        all  tows  for each  depth on the same day.
    3)  Record vertical temperature profile with a bathythermograph
        and  record other pertinent physical data at the time of
        each trawl haul.
d.  Sample processing
    1)  Separate  catch into groups by  species  and when possible
        into subgroups by  age  (young-of-the-year, yearlings,
        and  over-yearlings) on the basis of size.
    2)  Count all fish in  each subgroup  and obtain a total  y
        weight for the subgroups; exception:  when the catch of
        any  subgroup is too large to make enumeration
        practical, obtain  a total weight of the subgroup,
*This  does not constitute  an endorsement by the Lake Michigan
 Cooling Water Studies Panel or  the authors.
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    withdraw a subsample and obtain a total  weight and
    count, so as to permit determination of  total  number
    of Individuals in the subgroup by simple proportion.
3)  Process the catch made during each visit to each
    station as needed to reliably determine  the length,
    weight, sex, state of sexual  maturity and age  of
    individuals in each subgroup.
    a)  Length - Record total  length (distance from tip
        of snout to tip of caudal fin with lobes  compressed)
        in mm (inches) to nearest whole mm (0.1  inch).
    b)  Weight - Record fresh  (wet) weight in grams
        (ounces) to the nearest gram (0.1  ounce).
    c)  Sex and state of sexual  maturity.
    d)  Age determination -  The age of the younger sub-
        groups can often be  estimated from the length
        frequency distribution  for the species.   Scale
        samples provide a reliable method  for determining  the
        age of most fish.
           Remove 10-20 scales  from the left side  of a
        representative number  of  fish in each subgroup
        below the origin of  the dorsal fin and midway
        between the insertion  of  the fin and the  lateral
        line.   Although this should be the best location
        for obtaining scale  samples for age  and  growth
        studies, it is recommended that this be
        verified for the species  and stocks  being  sampled
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               in each geographic area, before large numbers of
               the scale samples are collected.
                   Place the scales from each fish in an indi-
               vidual envelope and record on the envelope the
               species sampled, the location, date, method of
               capture, and the individual length, weight, sex,
               and state of sexual maturity.
                   A plastic impression of the scale can be made
               in the laboratory to facilitate age determination
               (Smith, 1954).  A roller for producing plastic
               impressions is available from Wildlife Supply Co.,
               301 Cass Street, Saginaw, Mich. 48602*.
                   Pack calculation of body length in earlier
               years of life can be accomplished using the scales
               (Hile 1941, Tesch 1968).
       4)  Routine observations
           a)  Record any occurrence of disease or infestation
               by parasites.
           b)  Examine all trout and salmon (and other fishes
               for which tag and release studies are being con-
               ducted) for fin clips, tags, or other marks, and
               record mark, size and conditions of each marked
               fish.
       5)  Preserve samples for laboratory analysis as needed,
           after gathering the data prescribed in previous
rThis  does not constitute an endorsement by the Lake Michigan
 Cooling  Water Studies Panel or the authors.
                           263

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sections.
a)  Feeding habits
    Kill fish selected for analysis and preserve
    stomach contents immediately in 10 percent
    formalin.  Small fish can be preserved whole in
    formalin.  These fish should have the body cavity
    punctured or slit or injected with formalin to
    facilitate preservation (retard digestion) of
    their stomach contents.  For specimens too large
    to preserve and store conveniently, record length and
    weight and assign a code number.  Remove the stomach
    and preserve it in 10 percent formalin after labeling
    with the code number.
         Examine stomach samples, and record the frequency
    of occurrence and the total  volume of each kind of
    organisms eaten, following the methods of Windell
    (1968), or Wells and Beeton  (1963).
b)  Determination of contaminant level
    Kill fish selected for analysis and preserve by
    freezi ng.
         Perform analyses for PCBs ,  pesticides, heavy
    metals, etc., as needed, according to methods
    described in Section IV of this report.
c)  Fecundity estimates
    Small fish can be preserved  whole in 10  percent
    formalin and the ovaries can be removed  and ex-
    amined  in the laboratory.   Large fish should be
                    264

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        weighed,  measured,  and given  a  code  number.   The
        ovaries can then  be removed,  weighed fresh,  and
        preserved in 10 percent formalin  or  in  Gilson's
        fluid (Bagenal  and  Braum,  1968).
             Determine  fecundity according  to methods
        given in  Bagenal  and Braum,  1968.
             The  use of fecundity  data  (in  conjunction with
        information on  the  total  number of  eggs  spawned
        and the size and  sex composition  of  a population
        may be used to  estimate fish  stock  abundance
        (Saville  1964) .
Sample analysis
1)  Population size estimate
    a)  The catch statistics from  trawl samples  (together
        with those from gi 11 net, seine , plankton net, and
        pumped samples — see later  sections)  can  be applied
        toward an estimate  of total  population  based on
        estimates of catch  per unit  effort.   Some methods
        of estimating population from catch  statistics
        are given by Ricker (1958),  Chapman  (1961),
        Saville (1964), Robson and Regier  (1968), Beverton
        and Holt  (1957) and Gulland  (1969).
    b)  Other analyses  concerning  biological  interrelations
        will be outlined  in later  sections.
2)  Use data collected  from trawling  (and  from  gill  netting,
    plankton netting, seining, pumping, and  tagging — see
    later sections) to  determine the  importance  of the study
                        265

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            area as a spawning and nursery ground, and to determine
            the seasonal size distributions of the resident fish
            populations and some of the interrelations of these
            populations.
2.   Gill net sampling of juvenile and adult fish
    a.  Sampling location
        1)  Bottom gill net sets at all  stations 15 ft and deeper
            as shown in Figure VII - 3.
        2)  Oblique sets along center line of Figure VII - 3 at
            30' , 60' , and 120'.
    b.  Gear
        1)  Standard bottom gill net gangs each including 50 linear
            feet of 1-1/2-, and 100 linear feet each of 1-1/2-,
            2-, 2-1/2-, 3-, 3-1/2-, 4-, 4-1/2-, 5-,  5-1/2-, and
            6-inch mesh.  Each mesh size is a separate net and  all  of
            the nets are joined end-to-end, with nets of different
            mesh sizes interspersed randomly.
        2)  Two oblique gill nets.  One  gang with 1-1/2 inch mesh
            and one gang with  4-1/2 inch mesh.  Lengths will  depend
            upon the water depth where  fished.
        3)  Specifications
            a)  Net specifications are  those   proposed for
                standard bottom gill nets by the Great Lakes Fishery
                Commission and currently used by the Michigan
                Department of Natural  Resources.  The net is
                6 ft deep (float line to lead line).  Table
                VII - 2 contains specification for each mesh  size.
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Table VII - 2.   Gill net specifications for various mesh sizes
Stretched mesh
size (inches)
1-1/2
2
2-1/2
3
3-1/2
4
4-1/2
5
5-1/2
6
Net length
(feet)
50
100
100
100
100
100
100
100
100
100
Twine Size
110/3
110/3
210/2
210/2
210/2
210/3
210/3
210/3
210/3
104 thread
No. of meshes
deep
55
41
33
27
23
20
18
16
15
nylon 13
                          267

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b)  All thread to be used in making this gill  netting
    shall  be nylon of American manufacture.   Thread must
    withstand scalding process without injury.   Stretched
    measure is in inches when wet,  as  measured  with an
    8-ounce sliding weight gauge.   Measurement  is  to
    be made after webbing has been  soaked in  water for
    one-half hour or longer.   Webbing  is to  be  pre-
    shrunk and heat set, and knots  must hold  without
    slipping.   Measurement shall  be made of  at  least
    10 different meshes  chosen at  random, but well  away
    from the selvage for each piece of netting.  Mesh
    sizes  shall  not vary over 1/32  of  an inch.   All
    netting must be double selvage  top and bottom.
         The netting is  hung on No.  6  Starlite  braided
    nylon  maitre (or equivalent) with  No. 9  t-spun
    nylon  seaming twine  (or equivalent).  The nets  are
    hung on the  one-half basis, i.e.,  200 feet  of
    netting are  hung on  each  100 feet  of unstretched
    maitre.   Use regular aluminumgill  net floats,  and
    space  7-1/2  feet apart.   Attach a  1/3 pound  lead
    directly under each  float.
         All  specifications  refer  to the nets after
    they are constructed.   When the nets are  being
    hung,  the  maitre should be under a tension  of
    about  100  pounds;  allowance therefore needs  to  be
    made for the stretch of the maitre so that  when
    the tension  is released 200 feet of netting  will
    be on  100  feet of  maitre, and  the  floats will  be
                    268

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                spaced  properly.
    c.   Sampling frequency
        1)   Collect at  all  stations  monthly.
        2)   Make three  replicate  sets  at  each  depth  (overnight
            sets)  on successive  days.
        3)   Measure water temperature  and other  pertinent
            physical factors  at  the  time  of  each net set.
    d.   Sample processing
        1)   Separate catch  by species  and mesh size  and
            whenever possible by  age (young-of-the-year,
            yearlings,  and  older); for oblique sets  separate
            catch  by depth  also.
        2)   Determine age composition, length, weight, state  of
            sexual  maturity and  fecundity, and stomach contents
            of each subgroup  or  an adequate  subsample of each
            age group.
                 If necessary preserve subsamples  in 10 percent
            formalin for  processing  at a  later date.
        3)   See previous  section  on  sample preservation.
    e.   Sample analysis - See previous section on  sample analysis

3.   Seine sampling  for  juvenile  and  adult fish
    a.   Sampling locations  -  All  shoreline stations  shown  in
        Figure VII  - 3.
    b.   Gear
        1)   Gear should include  a nylon bag  seine, 1/2 inch
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           square mesh, TOO feet long and 8 feet deep with an
           8' x 8' x 8' bag of 1/4 inch mesh in the center.
           Seine should be constructed of strong (50 - 80 Ib.
           test) mesh.  The bottom line should be weighted to
           hold the net on the bottom while the net is being
           pulled; floats should be numerous enough to prevent
           sections of the top line from submerging.  A lead
           line of 30 strands of "Regal Rope" around a polypro-
           pylene core will conform to most bottom types.  One
           supplier of such nets is:   The Nylon Net Company,
           P.O. Box 592, Memphis, Tenn. 38101*.
       2)  Larger seines (12' x 1000') should be used where  the
           capture of large  salmonids is probable.
   c.   Sampling frequency
       1)  Collect at all stations monthly.
       2)  Make triplicate seine hauls across contours at each
           station on the same day.
       3)  Estimate wave heights and  measure water temperature,
           turbidity, and other pertinent factors at the time
           of each seine haul.
       4)  Sample processing - See previous sections.
       5)  Sample analysis - See previous sections.
*This does not constitute endorsement by the Lake Michigan
 Cooling Water Studies Panel or  the authors.
                         270

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4.   Plankton net sampling  for  fish  fry
    a.   Sampling locations
        All  stations  on  the  15 foot depth  contour should  be
        sampled as  shown in  Figure  VII  -  3,  plus  one  station  at
        the  intersection of  the centerline and  each of  the  follow-
        ing  depth  contours:  15,  30,  45,  60,  75,  90,  105, and
        120  feet.
             Sample the  0  (surface),  1-,  2-,  4-,  6-,  8-,  and
        10-meter depth  levels  within  the  water  column at  each of
        the  above  stations,  as water  depth permits.
    b.   Gear
        Gear should include  a  one-half  meter  nylon plankton net,
        351  micron  Nitex with  1/2-m ring  diameter, 'nylon  covered
        stainless  steel  bridle,  and PVC bucket  5"  in  diameter
        and  8"  long with 351 micron stainless steel bolting cloth
        window.   Length  of the net  is 2.5  meters.  One  source of
        nets of these specifications  is:   Wildlife Supply Company,
        2200 South  Hamilton  Street,  Saginaw,  Michigan 48602.   The
        approximate cost is  $130.00*.
    c.   Sampling frequency
        1)   Sample  all  stations  weekly  from May through September.
        2)   Make duplicate 5-minute tows  at each  depth  at each
            station on  the same  day.
        3)   Measure water temperature and  other pertinent physical
            factors at  the time  of  each plankton  net  tow.
    *This  does  not  constitute endorsement by  the Lake Michigan
     Cooling  Water  Studies Panel or the authors.
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    d.  Sample processing
        1)  Rinse organisms adhering to inside surface of net
            body into bucket and preserve them in 10 percent
            formal in.
        2)  Sort by species and developmental  stage (prolarvae,
            larvae, post larvae, or juvenile).
        3)  For each developmental  stage:  enumerate,  measure
            an adequate sample of individuals  (total  length in
            mm), and obtain a total dry weight.
    e.  Sample analysis - See previous  section.

5.   Pump sampling of fish eggs
    a.  Sampling locations
        All stations shallower than 75  feet shown in
        Figure VII - 3.
    b.  Gear
        Centrifugal lift pump passing bottom water through  #30
        screen with a flow meter to record  volume of  water
        samples.
             Specifications - None  available at  this  time.
    c.  Sampling frequency
        1)  Make duplicate 5-minute pumpings on  the bottom
            along the depth contour at  each station.
                 All stations must  be sampled  on the  same day.
        2)  Sample weekly, May 1 -  August 1 and  again  on
            December 15 and March 1.
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        3)   Measure water temperature and other pertinent
            physical factors  at the time of each pumping.
    d.   Sample processing
        1)   Sort eggs into major size (species) groups separating
            live (translucent)  eggs from those that are dead
            (opaque, fungused,  etc.)  and record the number in each
            subgroup.
        2)   Measure the diameters  of  an  adequate sample in each
            subgroup of live  eggs.
        3)   Record  the developmental  stage of live eggs in each
            subgroup, if possible.
    e.   Sample analysis - see previous  sections.

6.   Tagging or Marking of Fish
    Fish captured at the site can  be  tagged (or marked) to pro-
    vide information on the local  movements and lakewide migra-
    tion patterns.   Although  some  species, including the Pacific
    salmons, are known to range widely  throughout the lake, the
    extent  to which many important  native species undertake local
    and lakewide movements is poorly  known.  Knowledge of whether
    the fish found  at a cooling water use site are permanent
    residents of the site or  simply migrants passing through the
    area is important in evaluating the  impact of the plant on
    the fish populations of the lake.
    a.   Sampling location
        Capture, tag and release fish at any of the stations
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         shown  in  Figure  VII  -  3,  but  concentrate  on  those
         stations  shallower than  75  feet.
     b.   Gear
         1)  Tags  and  marks.
            a)   Fin clipping may  be suitable  for  short  term
                 population size  data  on  fish  other than  trout
                 and salmon (these salmonids are already  being  fin
                 clipped  for  various studies by state  agencies;
                 further  clipping  would cause  confusion).
            b)   Anchor spaghetti  tags  (FLOY tags*) or other
                 commercially available tag where  recognition of
                 individual fish  is  necessary  (i.e.,  growth and
                 movement studies),  or where fin clipping is
                 not recommended  (Rounsefell and Kash, 1946).
            c)   Dyes  or  pigments
                 Specifications:
                 Imbed biologically  inert  fluorescent  pigment in
                 fish  scales  or integument with compressed air.
                 This  method  permits simultaneous  marking of large
                 numbers  of fish with  a minimum of fish  handling;
                 the method may be suitable for fish  that are
                 sensitive to handling or  are  too  small  for tags
                 or fin clips.  Pigments  persist for  over one year
                 and fluoresce  under black (ultraviolet)  light.
                 Pigments and spraying apparatus are  available  from:
:This  does  not  constitute  an  endorsement by  the  Lake Michigan
 Cooling Water  Studies  Panel  or   the authors.
                            274

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            Wildlife Supply Co.*, and Day-Glo Color Corporation,
            4732 St. Clair Avenue,  Cleveland, Ohio 44103*.
            See Arnold (1966)  and Jessop (1973).
        d)  Hot or cold branding -  See Moav et al. (1960) and
            Raleight et al. (1973).
        e)  Radio or ultrasonic transmitters - See studies  of
            residence time in  thermal plumes discussed on
            Page 280 (Intensive Plume Studies).
    2)  Capture and recapture  equipment - Fish may be taken
        by any means that does  not reduce their viability.
        a)  Seine - 30 ft seine (61  deep) with knotless mesh
            (1/2" or less) to  reduce abrasion to  capture fish.
            One source of such nets  is the Nylon  Net Co.,
            P.O. Box 592, Memphis,  Tenn. 38101*.
        b)  Trap or fyke net - Nylon net with 8'  diameter
            mouth with 2 funnel-shaped  throats  on 2nd and  4th
            hoop.  Wings 50' long.   Whole net tarred.  Mesh
            size 1".  Such nets are  available from Nylon Net
            Co., P.O. Box 592, Memphis, Tenn. 38101*.  The
            approximate cost is $100.
        c)  Electrofishing - We can  make no specific recommen-
            dations at this time.
        d)  Hook and line - As appropriate.
c.  Sampling frequency
    1)  Tag and release fish as frequently as is  needed to
        permit  adequate description  of the movements of fish
        using the site.  Record data and location  of release
* This does not constitute an  endorsement by the  Lake Michigan
  Cooling Water Studies Panel  or the authors.
                          275

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            and if possible length and weight of each fish.
        2)  Recapture as part of general survey.
    d.  Sampling processing
        1)  Record any marked fish taken, the date and location
            of capture, and their lengths, and weights if possible,
        2)  Minimize handling; anaesthetize fish if necessary to
            prevent injury to fish during handling.
        3)  Release fish at capture site unless site-specific
            requirements indicate displacement studies of marked
            fish are also desirable.
    e.  Sample analysis
        Data on time and location of recapture should give
        indications of patterns and rates of movement or migration
        and thus help determine whether populations found at each
        site are local  or transient.  Further information on
        analytical procedures is found in Spigarelli  and
        Thommes (1973).

     Intensive Plume Studies
     These studies are  designed to describe the fish  community in
the discharge plume and the area immediately surrounding the plume
and will determine the  behavioral and pathological  responses of
fish to the physical, chemical, and biological environments that
exist in the plume.
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    It is difficult to present a detailed sampling plan that per-
mits a reliable characterization of the fish populations of heated
plumes, because adequate physical  plume measurements (including
data on sinking plumes)  are not available for most of the plants
now operating (or under  construction)  on Lake Michigan; further-
more,  fish populations in and around these plumes have received
little study until  relatively recently.  In general, the sampling
gear and methodologies described elsewhere in this report can be
successfully adapted to  local conditions for use in sampling the
plume  populations;  new approaches  such as electronic plume mapping
and fish locating and radio tracking may also be needed.

          Questions to be answered
     1.  What kinds and  numbers of fish are residing in the dis-
         charge plume; and what are the diurnal, seasonal, and
         annual patterns and trends?  (Priority 1, Category 3)
         a.   What is the age, size, and sex composition of each
             species composing the resident population and what
             are the diurnal and seasonal trends?  (Priority 2,
             Category 2)
         b.   What are the residence times within specific iso-
             therms in the plume,  of these fish (i.e., to what
             temperatures are these fish acclimated) and what are
             the diurnal, seasonal, and annual  trends?  (Priority 1,
             Category 3)
         c.   What percentage of the fish residing in the plume
             during the  colder months  of the year are killed or
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    made susceptible to predation when plume temperatures
    rapidly decrease to receiving water temperatures, be-
    cause of plant shutdown?  (Priority 2, Category 3)
d.  What percentage of fish killed by cold shock float
    on the surface where they are visible?  (Priority 1,
    Category 3)
e.  What percentage of the fish residing in a discharge
    plume are killed, incapacitated, or driven out of the
    plume during chlorination?  (Priority 2, Category 3)
f.  What percentage of the fish resident in the plume
    during the colder months of the year develop gas
    bubble disease symptoms and are killed, made suscep-
    tible to predators, or driven out of the plume?
    (Priority 2, Category 3)
g.  What percentage of the fish driven out of the plume
    during the colder months of the year suffer cold
    shock and death or are made more susceptible to
    predators residing outside the plume?  (Priority 2,
    Category 3)
h.  What percentage of the fish residing in the plume
    during the warmer months of the year, are killed
    or are shocked and made susceptible to predation
    when plume temperatures drop suddenly because of
    an upwelling that reduces intake water temperatures?
    (Priority 2, Category 3)
i.  Do fish residing in a discharge plume accumulate a
    significantly higher level of contaminants such as

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    mercury, PCBs,  pesticides, etc., than fish in adja-
    cent unheated lake water?  (Priority 2, Category 3)
j.  Does the discharge of waste heat into Lake Michigan
    lower the reproductive success of the lake's desirable
    species of fish, and/or increase the reproductive
    success of less desirable species of fish?  (Priority 1,
    Category 3)
k.  Are any of those species with low temperature or
    "winter chill" requirements (as determined by lab-
    oratory studies) found in heated plumes, and is their
    timing and duration of residence in the plume ade-
    quate to cause a reduction of reproductive success?
    (Priority 2,  Category 3)
1.  What kinds and numbers of fish spawn in areas im-
    pacted by the heated discharge?  (Priority 2, Category 3)
m.  What is the reproductive success of these fish and
    does it compare favorably with the success of members
    of the same stock  that spawned outside the heated
    discharge, or that spawned in the area before the
    plant was constructed and waste heat was released?
    (Priority 2,  Category 3)
n.  What kinds and numbers of fish are prevented from
    spawning in their  "ancestral" spawning areas by the
    heated discharge?   (Priority  2, Category 3)
o.  Will those fish that are prevented from spawning on
    an "ancestral" spawning ground (by the discharge of
                                                       i
    waste heat) be able to locate other suitable spawning '

                   279

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        grounds, or will their reproductive contribution be
        lost because they spawn in areas where the survival of
        eggs and fry will be low?  (Priority 2, Category 3)
    p.  Will the addition of heat to spawning grounds
        accelerate embryonic development and cause premature
        hatching?  (Priority 2, Category 1)
    q.  Will fry that hatch prematurely and out of phase
        with their normal food supply be able to find
        sufficient food to permit good growth and survival?
        (Priority 2, Category 3)
2.  What effect does cooling water use have on the availability
    of suitable food and feeding conditions for Lake Michigan
    fishes?  (Priority 2, Category 3)
    a.  Do fish inhabiting heated plumes in winter lose sig-
        nificant amounts of weight due to the unavailability
        of food?  (Priority 2, Category 3)
3.  Do heated effluents or intake flows serve as barriers to
    fish movements?  (Priority 3, Category  3)
4.  Does the discharge plume affect the numbers and types of
    fish trapped at the intake?  (Priority  2, Category 2)
5.  How does winter deicing by recirculation of heated
    effluent influence patterns of residence or entrapment
    of fishes at the intake?  (Priority 2,  Category 2)
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 Materials and Methods
Conduct simultaneous plume mapping and echolocation of
fish in the plume and in the unheated water surrounding
the plume to determine the abundance of fish within spe-
cific isotherms.   The methodology for a study of this
type is currently under development at the Point Beach
nuclear plant site by Argonne National Laboratory
(Spigarelli, et al.,1973a; Romberg and Spigarelli,  1972)
a.   Sampling location
    The heated plume and surrounding unheated lake  waters;
    sampling stations will not be geographically fixed
    because plumes change shape,  size, and location in
    response to wind and lake currents and level of plant
    operation.
b.   Sampling gear
    Data are collected continuously by electronic means
    with shipboard equipment.
c.   Sampling frequency
    1)   Conduct one or more complete plume mapping  and
        fish echolocation surveys each month for at least
        one year  until the seasonal patterns of distri-
        bution and abundance of the major fish species
        relative  to stable plume  isotherms are reliably
        established.
    2)   Conduct additional surveys as needed to deter-
        mine the  effect of upwellings, plant shutdowns
                  281

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            and chlorination on the distribution and movements
            of the fish populations of heated plumes and
            adjacent waters.
    d.  Sample processing
        See Spigarelli, et al.  (1973a) and Romberg  and
        Spigarelli (1972).
2.  Conduct intensive fish sampling with  nets (in conjunction
    with plume mapping  and fish echolocation  studies)  to
    determine the size, density,  composition, and condition
    of the fish populations in  heated discharges.
    a.  Sampling location
        Collect samples in the  heated effluent and  in  the
        surrounding waters where temperatures  are not
        elevated; whenever possible collect samples  within
        discrete isotherms.
    b.  Sampling gear
        Bottom trawls,  gill  nets (anchored and drifted),
        seines, lift and dip nets  may be  employed as the
        situation demands.
    c.  Sampling frequency - see  previous sections
    d.  Sampling processing
        1)  Sort catch  into subgroups by  net  mesh size,
            species,  and life stage or age group (young-of
            the-year, yearling, and over-yearling)  and  obtain
            and record  a total  weight for each subgroup.
            Count and record all  individuals  in each subgroup
            when number is small,  otherwise count and weigh
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            and record data for a representative sample of
            the subgroup to permit later expansion of the
            data by simple proportion.
        2)  Collect the following according to procedures
            outlined in Materials and Methods  Section of
            Before and After Studies  (Page 260).
            a)   Scale samples (to permit estimates of age
                composition and growth  in length and weight;
                includes length-weight-sex data).
            b)   Stomach contents  (to  establish food habits
                and general level of  feeding).
            c)   Whole fish (for analyses of concentrations
                of pollutants such as DDT, PCBs,  heavy
                metals, etc.);  uptake and concentration of
                some pollutants is higher at elevated
                temperatures and  fish in heated plumes  may
                be accumulating these materials more rapidly
                than those in unheated  lake water.
        3)  Examine fish and record:
            a)   Any brands, tags, fin clips or other
                identifying marks
            b)   Incidence of infectious  diseases or parasites
            c)   Symptoms of gas bubble  disease.
3.   Conduct  studies to determine  residence time  of individual
    fish in  the plume,  and temperatures  to which these  fish
    are acclimated under stable plume conditions.
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Residence time data for individual fish will permit
estimation of the turnover rate of the populations in
the plume.  Data on residence time and acclimation tempera-
ture will also permit more precise judgments concerning
temperature dependent effects of cooling water use.  For
example, when the acclimation temperature of the plume
population is known, data from laboratory temperature
tolerance studies can be used to predict whether an
interruption of the discharge of a heated effluent would
cause low temperature mortality among the plume residents.
It will also be possible to estimate the degree of repro-
ductive impairment occurring among populations of yellow
perch that overwinter in heated plumes (due" to their
winter chill  requirements not being fully met), when
both the population turnover time and acclimation temper-
ature are known.

No single method is entirely suitable for determining
residence time and acclimation temperatures of fish
inhabiting the heated discharge plume and several
complementary methods may have to be applied.
Deep body temperature measurements (Spigarelli et al.,
1973b) made on fish immediately after capture  and
removal from the water give some idea of the temperatures
experienced immediately prior to capture.  Deep body
                    284

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temperatures can be measured by inserting the tempera-
ture sensing probe of an electronic thermometer into the
rectum or muscle tissue of the fish; if the former method
of insertion is used, the fish can also be tagged or
marked and released.  Body temperature measurements
have been made at the Point Beach nuclear plant by the
Argonne National Laboratory (Spigarelli et al., 1973b).

Marking fish by branding, removal of fins, spraying with
fluorescent pigment or the application of an external
tag may yield information on length of plume residence
and migration tendencies (See discussion of tags and
marks on page 273).

Thermoluminescent dosimeter tags (Romberg et al., 1972)
appear to have promise for use as short-term integrating
temperature recorders; they can also trace long-term
movements of the tagged fish.

Temperature sensitive transmitters implanted in fish and
monitored by radio-tracking systems offer perhaps the
greatest potential for obtaining precise, detailed thermal
histories of individual  fish.   Data can be collected
continuously to determine residence times of individual
fish within specific isotherms.  A system using shore
based receivers and capable of tracking several  fish
                      285

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    simultaneously is under development by University of Wisconsin
    researchers for use at the Point Beach nuclear plant.

4.   Conduct studies to determine behavioral  responses of fish
    populations to upwellings of water from the hypolimnion,
    plume shifts, and chlorination.

    All  of these events can result in sudden exposure of the
    plume fish population to  temperatures  considerably lower
    than those to which they  are acclimated.  During upwelling,
    the  temperature of the water entering  the plant cooling
    system intake may drop as much as IOC  (18F)  in a few
    hours, causing the discharge temperature and the inshore
    water temperature to fall  by a similar amount.  Plume
    shifts in response to wind and lake current  changes  occur
    relatively frequently and may cause portions of the  plume
    population to drift away  from the discharge  in isolated
    "lenses"  of heated water  that can be observed when plume
    shifts occur.

    Although  very low concentrations  of chlorine are lethal
    to  some fish (trout and salmon and possibly  others),
    studies have shown that fish may  be able to  detect and
    avoid even sublethal  concentrations.   As a  consequence,
    chlorination of cooling waters,  especially  during the
    colder months  of  the year,  may force fish residing in
    the  plume to leave the heated plume waters,  thereby
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         risking cold shock and low temperature death; those that
         remain in the plume may receive lethal exposures to chlor-
         ine.

         No single method is entirely suitable for documenting
         behavioral responses of plume fish populations to sudden
         changes in water temperature or to chlorination (which
         may result in the population moving out of the heated
         plume to areas  with lower temperature).  A combination
         of the methods  detailed in the section on plume mapping
         and fish location and those which  propose to determine
         plume residence time and  acclimation temperatures will
         be adequate to  the task (see also  Kelso,  1974).

     On-site Bioassays
     These studies are required to produce  data of a site specific
nature.   For example,  chlorine toxicity may vary widely with water
quality, which in turn may vary widely among sites.   Therefore,
chlorine toxicity studies should be conducted at each cooling water
site where chlorination  is practiced.

          Questions to be Answered
     1.   What are the  acute and chronic effects of intermittent
         chlorination  on fish in the thermal discharge area  and
         how do these  effects vary with species, life stage,
         water temperature and other seasonal  changes in  lake
         water quality?   (Priority 2,  Category 2)
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2.  What are the acute and chronic effects on fish in the
    thermal discharge area of cold shock caused by plant
    shutdown?  (Priority 2, Category 2)
3.  Is there a higher incidence and virulence of infectious
    of contagious diseases among fish in the plume than
    among fish in unheated areas of the lake?  (Priority 2,
    Category 3)
4.  Do fish in the plume exhibit symptoms of gas bubble
    disease and if so, what are the consequences to the fish
    that are displaying those symptoms?  (Priority 2, Catego-
    ry 3)

     Materials and Methods
1.  Effects of intermittent chlorination on caged fish held
    in the thermal  discharge.   Recommended procedure:  see
    Basch and Truchan (1971).
2.  Acute and chronic effects  of continuous and intermittent
    chlorination and temperature on fishes found in power
    plant thermal  plumes.   Recommended procedure:   Arthur
    and Eaton (1971).
3.  Effects of plant shutdown  on caged fish held in the
    thermal discharge.  Recommended procedure:   see Basch
    and Truchan (1971) for details  on cage construction and
    installation;  see Brett (1952)  and Fry, Hart,  and Walker
    (1946) for details on  conducting thermal  bioassays and
    interpreting results under conditions of constant and
    changing temperature.
                      288

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     4.  Effects of plume residence on incidence of gas bubble
         disease.  Recommended procedure:  No specific procedure
         has been developed that appears totally satisfactory for
         direct application to all Lake Michigan situations; but
         see Bouck etal. (1970), and Ebel (1969) who provide
         background information on GBD; DeMont and Miller (1971)
         who report the first incidence of GBD among fish in a
         thermal plume and Otto (1973) who provides information on
         the tolerance of Lake Michigan fishes to GBD.
     5.  The rate and severity of infection of contagious diseases
         among caged fish in a thermal plume.   Recommended pro-
         cedure:  None developed at this  time  but see Plumb
         (1973).

     Laboratory Studies
     Laboratory studies produce information on the physiological
and ecological  requirements  and tolerances  of  organisms,  that can
be used for independent interpretation and  verification of field
observations and field bioassay studies.   It is  our intent that
these laboratory studies  be  broad in  scope  and applicability of
results so  that the  necessity  for repetition as  part of the  demon-
stration of effect  at  each  plant is precluded.

          Questions  to be Answered
     1.  What are the  preferred and avoidance  temperatures of
         Lake Michigan fishes?  (Priority 2, Category 2)
     2.  How are fish  fry and  eggs  affected by the  shear  forces
                           289

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    generated by turbulent cooling water?  (Priority 3,
    Category 3)
3.  What are the temperature tolerances of the egg, larvae,
    juvenile, and adult life stages of the fishes of the
    lake?  (Priority 1, Category 2)
4.  What are the effects of sublethal exposure to elevated
    temperatures and rapid temperature drops on fish repro-
    duction and predator avoidance?  (Priority 2, Category 2)
5.  What are the effects of temperature on the feeding
    requirements and on the growth and conversion efficiency
    of fishes?  (Priority 3, Category 2)
6.  What are the swimming capabilities of larval  and juvenile
    Lake Michigan fishes relative to power plant  intake current
    velocities?  (Priority 2,  Category 2)
7.  What are the effects of temperature on the uptake of
    pesticides and other contaminants by fish residing in the
    plume?  (Priority 3, Category 2)

    Materials and Methods
1.  Preferred and avoidance temperatures of Lake  Michigan
    fishes.  Recommended procedure:  See McCauley and Tait
    (1970), and Meldrim and Gift (1971).
2.  Studies of the deformation and disruption of  fish fry and
    fish eggs in turbulent, shear-flow conditions.   Recommended
    procedure:   No procedure for experimentation  has yet
    been developed.   The problem was discussed by Goodyear
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    and Coutant (U.S.  Atomic Energy Commission,  1973);
    see also Cox and Maxon (1971),  Csanady (1973), Coutant
    and Kedl (1975), and Pommeranz  (1974).
3.  Temperature and tolerance of larval,  juvenile, and
    adult fish.  Recommended procedure:   Use method of  Brett
    (1952) for sudden  continuous exposure to an  elevated
    constant temperature.
4.  Effect of sublethal  thermal  shock  on  the ability of larval
    and juvenile fishes  to avoid predation.   Recommended
    procedure:   See Yocom  and Edsall  (1974), Coutant
    et al. (1974).
5.  Swimming speeds of juvenile  and larval inshore fishes of
    Lake Michigan.   Recommended  procedures:   Methods are
    currently under development  by  T.G.  Yocom at the Great
    Lakes Fishery  Laboratory, Ann Arbor,  Michigan; see  also
    Houde (1969a).
6.  Effects  of temperature on food  intake, conversion effi-
    ciency,  and growth of  juvenile  and adult Lake  Michigan
    fishes.   Recommended procedure:   See  McCormick et al.
    (1971 ),  and Brett  et al.  (1969) .
7.  Effects  of temperature on maturation, spawning, fertili-
    zation,  and embryo survival  of  fishes.  Recommended
    procedure:   See Hokanson  et  al .  (1973),  and  Colby and
    Brooke (1970).   The  National  Water Quality Laboratory,
    Duluth,  Minnesota  has  also developed  a procedure for
    determining temperature  requirements  for the maturation
    of the gonads  and  reproductive  success of the  yellow
                         291

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         perch  (MS  in preparation) that should be suitable for
         investigating these temperature requirements of other
         Lake Michigan fishes.
     8.  Effects of elevated temperatures on the rate of uptake
         and concentration of toxic materials directly from lake
         water  by fish.  Recommended procedures:  See Reinert
         etal.  (1974), Reinert (1970), Willford etal. (1973), and
         MacLeod and Pessah (1973).

     Lakewide Studies
     Lakewide fish stock assessment is needed to determine the
distribution and abundance of fish in Lake Michigan and to obtain
the vital statistics including the age composition and age-specific
birth, death, and growth rates of the populations.  These data, wheiy
treated according to currently accepted methods for the analysis
of fish population dynamics will  permit an evaluation of the lake-
wide effect of  cooling water use  on the fish populations of Lake
Michigan.
     Lakewide studies of the scale needed to evaluate the effects
of cooling water use on Lake Michigan fish will require careful
planning and execution if useable results are to be obtained.
Studies to assess the fish populations of the lake are already
underway by the various state and federal resource protection and
management agencies with proprietary interest in the lake.  Any
additional studies designed to describe these populations for the
purpose of determining cooling water use effects should be closely
coordinated with these ongoing efforts.
                           292

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     We have not attempted to present a review of the ongoing
fish population assessment activities on the lake, but reports of
these studies may be seen in the minutes of the annual Lake Michi-
gan Lake Committee Reports of the Great Lakes Fishery Commission.
Recently completed estimates of biomass for several  Lake Michigan
fish populations are available in Fisheries Report No. 1813 of
the Michigan Department of Natural  Resources (1974)  and in Edsall
et al.  (1974).
     The sampling program presented in the "Materials and Methods"
Section that follows, if conducted  independently of  ongoing
assessment studies,  is the minimum  effort that would permit
adequate description of the areal and depth distribution and rela-
tive abundance  of the populations of important fish  in the lake
(Item 1 in the  "Questions to be Answered" Section).   Coordination
of the  Lakewide Studies program with those of the various resource
agencies may permit  a reduction in  the effort required of the
Utilities  as  outlined in the Materials and Methods  Section that
follows.
          Questions  to be Answered
      1.  What  are the areal and depth distributions and relative
          abundance  of the various  fish populations  of the lake
          throughout the year?  (Priority 1, Category 2)
      2.  What  is the absolute size (age specific numerical
          abundance  and biomass) of each of the populations of
          fish  in Lake Michigan?  (Priority 1,  Category 3)
      3.  What  are the age specific rates of growth, reproduction,
          mortality  (including fishing mortality) and the food
          habits for each population of Lake Michigan fish
                             293

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      (Priority 2, Category 3)
  4.  What magnitude of age specific loss or damage caused
      by cooling water use can each population sustain without
      a significant decline in productivity and in the ability
      of each of these populations to recover to former levels
      of importance and abundance if the cause of loss or
      damage from cooling water use is removed?  (Priority 1,
      Category 3)

      Materials and Methods
Trawl sampling of juvenile and adult fish
a.  Sampling location - Cross-contour sampling transects, at
    least every 50 miles of lakeshore.   Trawl  hauls at 2.5,
    5, 7.5, 10, 12.5, 15, 17.5, 20, 25,  30, 35, 40, 45, 50,
    60,  70, and 80 fathoms across each transect (parallel to
    the  bottom contours).
b.  Gear - See Materials and Methods in  Before and After
    Studies (Page 260).
c.  Sampling frequency
    1)  Visit all  stations in spring and in fall  for at least
        one year.
    2)  See additional notes on frequency in Materials and
        Methods Section of Before and After Studies (Page 261).
d.  Sample processing - See processing information in Materials
    and  Methods Section of Before and After Studies (Page 261).
e.  Sample analysis - See Materials and  Methods Section of
    Before and After Studies (Page 265).
                         294

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2.   Gill net sampling  of juvenile  and  adult  fish
    a.   Sampling location
        Cross-contour sampling transects,  every  50  miles  of
        shoreline.
        1)   Bottom  gill  net sets  at 1,  5,  10,  15,  20,  30,  40,
            50,  60,  70,  and 80 fathoms  across  each  transect
            (nets  set parallel to bottom contours).
        2)   Oblique  gill  nets  set at  5,  15,  and  30  fathoms across
            each transect  (parallel  to  bottom  contours).
    b.   Gear -  See  gill  net specifications  in  Materials  and
        Methods  Section  of Before and After  Studies  (Page  266).
    c.   Sampling frequency
        1)   Visit  all stations in spring and in  fall.
        2)   See  discussion of  frequency  in  Materials  and
            Methods  Section of Before and  After  Studies  (Page  269).
    d.   Sample  processing  - See processing  in  Materials  and Methods
        Section  of  Before  and  After Studies  (Page  269).
    e.   Sample  analysis  -  See  analysis  of  samples  (Page  265).

3.   Seine  sampling  for juvenile and adult  fish
    a.   Sampling location
        Cross-contour sampling transects,  every  50  miles
        of  lakeshore.

        Seine hauls  in beach zone water  (0-10  ft).
    b.   Gear -  See  Materials and  Methods of  Before  and After
        Studies  (Page 269 ).
                             295

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c.  Sampling frequency
    1)  Visit all stations in spring and fall  for at least
        one year.
    2)  See sections on sampling frequency in  Materials  and
        Methods of Before and After Studies (Page 270).
d.  Sample processing - See discussion of processing in
    Materials and Methods of Before and After  Studies
    (Page 261 ).
e.  Sample analysis - See analysis of samples  in  Materials and
    Methods of Before and After Studies (Page  265).

Plankton net hauls for fish fry assessment (see Wells.  1973).
a.  Sampling locations
    Cross-contour sampling transects, at least every 50  miles
    of lakeshore.
    Sampling stations at 15, 30, 45, 60, 75, 90,  105,  and
    120 feet.
    Sample the 0 (surface), 1-, 2-, 4-, 6-, 8-, and  10-meter
    depth levels within the water column at each  of  the  above
    stations, when water depth permits.
b.  Gear - See Materials and Methods of Before and After
    Studies (Page 271).
c.  Sample frequency - See Materials and Methods  of  Before
    and After Studies (Page 271).  Sampling to continue  for
    at least one year.
d.  Sample processing - See Materials and Methods of Before
    and After Studies (Page 272).
                          296,,

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    e.   Sample analysis  -  See  Materials  and  Methods  of Before
        and After Studies  (Page  265).
5.   Pump sampling of fish  eggs
    a.   Sampling locations
        Cross-contour sampling transects,  at least every 50
        miles  of lakeshore.
        Make triplicate  5-minute pumpings  on the  bottom along
        the contour at each  station  at  0.5,  1,  1.5,  2.5, 3,
        3.5, 4,  4.5, 5,  7.5,  and 10  fathoms.
    b.   Gear - See Materials  and Methods  of  Before and After
        Studies  (Page 272).
    c.   Sample frequency - See Materials  and Methods  of Before
        and After Studies  (Page  272).   Sampling  to continue for
        at least one year.
    d.   Sample processing  -  Materials and  Methods  of  Before and
        After  Studies (Page  273).
    e.   Sample analysis  -  Materials  and  Methods  of Before and
        After  Studies (Page  265).
                            297

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                        LITERATURE CITED
Adair, W. D. and D. J. Demont. 1970.  Effects of thermal  pollution
    upon Lake Norman fishes.  N. Carolina Wildlife Res,  Comm.,
    Summary Report Job IX-C, Raleigh, N. C.
Arnold, D. E. 1966.
    Bureau of Sport
    44 pp.
          Marking fish with deys and other chemicals
          Fisheries and Wildlife, Technical  Paper No
                                  10
Arthur, J. W., and J. G. Eaton, 1971.
    amphipod, Gammarus pseudolimnaeus
    Pimephales
      promelas
FTsh
   Chloramine toxicity to the
  and the fathead minnow,
Res.  Board Can.  28:  1841.
Bagenal , T. B. , and E. Braum, 1968.   Egg.s and early life history.
    In  W.E. Rlcker (ed.).  Methods  for assessment of fish  pro-
    duction in fresh waters.  I.B.P.  Handbook No.  3.  Blackwell
    Scientific Publications, Oxford  and Edinburgh.  313 pp.

Basch, R., and J. Truchan, 1971.  A  caged fish study  on the  toxicity
    of intermittently chlorinated condenser cooling waters  at the
    Consumers Power Company's J. D.  Weadock Power  Plant, Essexville,
    Michigan, December 6 - 10, 1971.   Bur.  Water Manage., M1ch.
    Water Resources  Commission.
Basch, R. E. and J. G. Truchan. 1973
    residual chlorine concentrations
    Resources Comm.  Bureau of Water
    Natural Resources.  37 pp.
                             Interim report on  calculated
                           safe for fish.   Mich.  Water
                           Management,  Mich.  Dept.  of
Beck, A. D. and D. C. Miller, 1974.   Analysis of inner plant passage  on
    estuarlne biota.  In:  Electric  power and the civil  engineer:
    Power division specialty conference.   Am. Soc. Civil  Eng.
    New York.  676 pp.
Beverton, R. J. H., and S. J
    ploited fish populations
    533 pp.
                    Holt,  1957.   On
                     Fishery invest
                the  dynamics
                ,  London.(2)
                       of ex-
                        19,
Bouck, G. R. G. A. Chapman, P.  W.  Schneider,  and D.  G.  Stevens.  1970
    Observations on gas bubble  disease in adult Columbia River sock-
    eye salmon Onchrhynchus nerka.   Pacific Northwest Water Labora-
    tory (FWQA), Corvallis, Oregon.   19 pp.

Brett, J.
    genus
R. 1952.  Temperature
Oncorhynchus.  J.  Fish
  tolerance in  young
   Res.  Board  Can.
               Pacific salmon,
               9:  265-323.
Brett, J. R., J. E. Shelbourn, and
    body composition of fingerling
    in relation to temperature and
    Board Can. 26:  2363-2394.
                         C.  T.  Shoop.   1969.  Growth  rate
                         salmon,  Oncorhynchus nerka,
                         ration size.  J.  F1sh.  Res.
                            298

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Brungs, W.A.  1971.   Chronic effects of constant elevated tempera-
     tures on fathead minnow (Pimephales promelas Rafinesque).
     Trans.  Am.  Fish. Soc.  100:659-664.

Chapman, D.G. 1961.   Statistical  problems in dynamics of exploited
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Clark, J.  and W.  Brownell.   1973.   Electric power plants in the
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Colby, P.O.  and  L.T.  Brooke.  1973.  Effects of temperature on
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Coutant, C.C. 1973.   Effect of thermal  shock on vulnerability of
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Coutant C.C., H.M.  Ducharme, Jr.,  and  J.R. Fisher,  1974.
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De Vlaming,  V.L.  1972.   Environmental  control of teleost repro-
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                             299

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Edsall, T, A, and T, Gj, Yocom, 1972,  Review of recent technical
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                             300

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Houde, E.D. and J.L. Forney.  1970.   Effects of water currents
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Hubbs, C, and K.  Strawn,  1957.   The effects of light and tempera-
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Hubbs, C.L. and K.F. Lagler,  1958.   Fishes of the Great Lakes
     Region.  Univ.  Mich. Press, Ann Arbor, 213 pp.

Jessop, B.M. 1973.   Marking alewife fry with biological stains.
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Kelso, J.R.M. 1972.   Conversion, maintenance, and assimilation
     for walleye,  Sti zostedion  vitreum vitreum, as affected by
     size, diet,  and temperature.  J. Fish Res. Board Can.
     29:1181-1192.

Kelso, J.R.M. 1974.   Influence  of a thermal effluent on movement  of
     brown bullhead  (Ictalurus  nebulosus) as determined by  ultrasonic
     tracking.   J.  Fish Res.  Board  Can. 31:1507-1513.

Macek, K.J., C. Hutchinson, and O.B. Cope. 1969.  The effects of
     temperature  on  the susceptibility of bluegill and rainbow trout
     to selected  pesticides.   Bull. Env.  Contam. Toxicol.  4:174.

MacLeod, J.C. and  E. Pessah,  1973.   Temperature effects on  mercury
     accumulation,  toxicity,  and metabolic rate in rainbow  trout
     (Salmo gairdneri).  J. Fish. Res. Board Can. 30:485-492.

Marcy, B.C., Jr.  1967.  Resident fish population dynamics  and
     early life history studies of  the fishes in the lower  Connecticut
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Marcy, B.C., Jr.  1973.  Vulnerability and survival of young
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     J. Fish. Res.  Board  Can.  30:1195-1203.

Marcy, B.C., Jr.  1974.  Vulnerability and survival of entrained
     organisms  at  water intakes, with emphasis on young fishes.
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McCauley, R.W., and  J.S.  Tait.  1970.  Preferred temperature of
     yearling lake  trout, Salvelinus namaycush.  J.  Fish.  Res.
     Board Can. 27:1729-1733.

McCormick, J.H.,  B.R.  Jones,  and R.F. Syrett. 1971.   Temperature
     requirements  for  growth  and survival of larval  ciscoes
     (Coregonus a r t e d i i Le  Sueur).   J. Fish.  Res. Board Can.
     28 (6):924-927.
                             301

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Meldrim, J.W., and J.J. Gift. 1971.  Temperature preference,
     avoidance, and shock experiments with estuarine fishes.
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     Del. 74 pp.

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     Report No. 5. 105 pp.

Michigan Department of Natural Resources. 1974.  Estimates of biomass
     of principal fish species in the Great Lakes.   Fisheries
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Moav, R., G. Wohlfarth, and M. Lahman. 1960.  An electric instrument
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Ordal,  E.J.  and R.E. Pacha. 1963.  The effects  of temperature on
     disease in fish.  In:  Water temperature.   Influences, effects
     and control. Proc.T2th Pacific N.W. Symp. Water Poll.
     Res. p. 39-56.

Otto, R.G. 1973.  Report to Commonwealth Edison Co.  Effects of
     gas supersaturation of fishes in southwestern  Lake Michigan.
     Industrial Bio-Test Laboratories, Inc.   Project XV, I.B.T.
     No. W 1286, January 1972 - April 1972.   48 pp.

Plumb,  J.A.  1973.  Effects of temperature on mortality of finger-
     ling channel catfish (Ictalurus punctatus) experimentally
     infected with channel catfish virus.  J.  Fish. Res. Board Can.
     30.568-570.

Pommeranz, T. 1974.  Resistance of plaice eggs  to mechanical stress
     and light.  In:  J.H.S. Blaxter [ed.]  The  early life history
     of fish.  SprTnger-Verlag.  New York.  765  pp.

Powles, P.M. 1974.  Survival of Australian  anchovy  (Engraulis
     austral is) eggs and larvae in a heat trap.  In: jTH.S. Blaxter
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Raleigh, R.F.,  J.B. McLaren, and D.R. Graff.   1973.  Effects of
     topical location,  branding techniques  and  changes in hue on
     recognition of cold brands in centrarchid  and  salmonid fish.
     Trans.  Am. Fish. Soc. 102(3):637-641 .

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     Pest. Monit. J. 3:233-240.

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     temperature on accumulations of mercury and Ł,Ł' DDT from
     water by rainbow trout (Salmo gairdneri).   J.  Fish. Res. Board
     Can. 31:1649-1652.
                              302

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                            303

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     Scientific  Publications,   Oxford  and  Edinburgh.   313  pp.

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                           305

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                  SECTION VIII





MEASUREMENT OF THE EFFECTS OF COOLING WATER USE



      ON ENTRAPPED AND ENTRAINED ORGANISMS

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Section VIII   MEASUREMENT OF THE  EFFECTS OF COOLING WATER USE
               LON ENTRAPPED AND ENTRAINED ORGANISMS
               *i     1
                           Table of  Contents
Introduction	310
Entrapped Organisms.  	  311
     Introduction  	  311
     Monitoring Program for Existing  Water  Intakes  	  312
           Objectives .	31.2
           Sampling Frequency  	  313
           Sampling Methods	313
           Sampling Data Required	313
     Monitoring Program for New and Proposed  Water  Intakes	314
           Objectives .	314
           Methods of Investigation  	  314
Entrained Organisms   	  314
     Introduction   	  314
     Phytoplankton  	  316
            Introduction  	  316
           Objectives	317
           Methods of Investigation	k  ....  317
           Methods of Sampling	1  •          323
            Sampling  Interval	I  ....  324
            Sampling  Frequency  	1  	  324
            Sampling  Site Selection	'/....  324
            Special  Problems	  325
                                     308

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Zooplankton and  Entratnable Benthos. , .  .  .   .   .   .   ...   . .  .   .325
     Objectives   .   .   .   .  .  .  ....   .   .   .   .   .   .   .   .   .326
     Methods of  Sampling   .  .  .	   .   .   .   .   .   .326
     Sampling Frequency and Interval  	 328
Ftsh .   .   .	 328
     Introduction.   .	328
     Objectives	328
     Questions to be answered.  	 329
     Methods of  Investigation and Sampling  	 331
           Plant Entrainment	331
           Plume Entrainment	 335
Priority Research   	 337
Literature Cited    	 341
                                309

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Section VIII, MEASUREMENT OF THE EFFECTS OF COOLING WATER USE ON
                ENTRAPPED AND ENTRAINED ORGANISMS

                           Introduction
       The possible ecological effects of entrapment   and en-
   trainment of Lake Michigan organisms in water intake systems  are
   of significant concern.   Entrapment  is defined here as the  trap-
   ping or confinement of organisms within an intake  system,  or  im-
   pingement of organisms on screening devices  such that the  organ-
   isms are unable to return to their natural habitat.   Organisms
   with potential for becoming entrapped are of a size  sufficient  to
   preclude passage through a  3/8 inch  screen mesh  and whose  swim-
   ming ability is insufficient to permit them  to swim  against  in-
   ward moving intake currents.  Fish are of primary  concern  although
   larger invertebrates may also become entrapped or  impinged.
       Entrainment is defined as a process whereby small organisms
   in the lake water are passively carried with the cooling water
   into an intake structure, through a cooling  system and thence back
   to the lake.  Entrained  organisms are small  organisms drawn  into
   an intake system whose size does not preclude their  passage   through
   a  3/8  inch screen mesh and on through a cooling  water system.
   Planktonic forms entrained in the effluent plume by  mixing processes
   are also included within the category of entrained  organisms.  These
                               310

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two types of entrainment are referred to as plant and plume entrain-
tnent, respectively.   Entrainable organisms include members of the
phytoplankton and zooplankton communities, small  fish, fish eggs
and larvae and small  benthic forms  periodically in the water column.
     The published literature does  not contain an abundance of
information relating  to the problems of entrapment and entrainment.
However, a considerable amount of information has been collected
at operating power plants and is made available in published reports.
A report prepared by  the Lake Michigan Cooling Water Intake Technical
Committee, 1973,  specifically relates to water intakes on Lake Michi-
gan.  This contains  an excellent review and discussion of intake
structures, and entrapment problems on Lake Michigan.  Others of
more general context  include Sonnichensen, et al., 1973;  Sharma,
1973; and U.S. EPA,  1073; these are excellent review documents on
cooling water intakes and entrapment problems.  A recent  publica-
tion edited by Jensen (1974) contains 35 papers dealing with both
entrapment and entrainment research at power plants and other
water intake facilities.  Papers in this report cover the entire
spectrum of concern  from phytoplankton entrainment to fish entrap-
ment and include  current bibliographic citations  for further
reference.

                      Entrapped Organisms

Introduction
     The entrapment  of organisms in a water intake system depends
on the area of the lake from which  the water is withdrawn, the
                            311

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physical arrangement and hydraulics of the particular system and
the specific location of the intake, whether it is onshore, off-
shore at the surface or submerged.  The proximity of an intake to
aruds highly populated with lake organisms, spawning grounds, etc.,
are also important in determining the numbers of organisms which
may be entrapped.
     Before the impact of intake systems on populations of Lake
Michigan organisms can be evaluated, information is needed on the
numbers of species, and life history stages currently being en-
trapped.  The program outlined below is designed to document the
numbers of organisms which are or may be entrapped or impinged
at intakes.  It is suggested that these data be evaluated in terms
of such factors as intake location and type to determine if certain
areas of the lake or specific intake designs contribute  dispro-
portionately to the entrapment of organisms.  This information is
essential to the evaluation of the impact of entrapment on Lake
Michigan populations.  If design and location factors are signifi-
cant, it will also be necessary for the proper evaluation of exist-
ing intake systems and for the design of future intake structures.
Monitoring Program for Existing Water Intakes
Objectives
     The primary objective of this program is to determine the
daily and seasonal variations in numbers, size and weight of all
species entrapped in intake systems.  This monitoring scheme is
adapted from that suggested by the Lake Michigan Cooling Water In-
take Technical  Committee, 1973.
                             312

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     Sampling Frequency
     Sampling should be conducted through  one calendar year.
Data on organisms  which become  impinged  on the intake screens
should be collected daily.
     Sampling Methods
     Collection of large invertebrates,  juvenile and adult fish
impinged on screening devices  can be  accomplished using collection
baskets in the backwash sluiceway.   Mesh size of the collection
baskets should be  equal to  or  smaller than the intake screen  mesh.
     Sampling Data Required
1.   Plant operating data required  during  monitoring period:
     a.  Flow rate
     b.  Temperature - intake  and discharge
     c.  Time started, duration and amount of warm water
         recirculated for intake deicing.
     d.  Total residual chlorine contained in recirculated
         water during condenser cleaning.
     e.  Current velocity at intake(s)  over the range of
         water volumes used in  plant  operation.
     f.  Number of times screens are  operated between sampling
         intervals.
2.   Data required from biological  collections:
     a.  Species,  life stage,  number  and size of each organism
         collected from the screens.
     b.  Volume of water sampled.
     c.  Number, length, weight, and  age group (young-of-the-year,
         yearlings ar.J older)  of all  fish  collected from
         screening devices.
                            313

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      d.  Representative samples of each species for determina-
          ion of sex and breeding condition.
      e.  Numbers of naturally occurring dead fish in the area
          ahead of the intake screening system should be estimated.
Monitoring Program for New and Proposed Water Intakes

      Objectives
      The primary objective for preoperational biological sampling
is to determine the abundance of potentially entrappable organisms
in the area of proposed intakes and to determine if fish are using
the area as spawning, nursery or feeding grounds, and/or as migra-
tion routes.

      Methods of Investigation
1.    Field studies to obtain this information are discussed in
      the fisheries, benthos, and microbiology sections of this
      report.
2.    Model studies may be necessary to determine the optimal  de-
      sign of intake structures which would reduce potential loss
      through entrapment or impingement.
3.    Initial operation: When a new intake system becomes operational
      it should be closely monitored for one year as prescribed above
      for existing intakes.
4.    Design modification:  If a new intake system entraps an  un-
      acceptable number of organisms, design modifications should
      be considered, tested as per 2 above, and implemented.
                     Entrained Organisms
Introduction

     Organisms in the intake water not stopped by the plant screens,
diverted, or otherwise removed from the circulating water intake
flow, pass through circulating water pumps, steam condensers and,
                            314

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related appurtenances and back into the receiving water.  Passage
through the cooling system may place stresses on the organisms
including:  mechanical  abrasion due to turbulence and irregular
surfaces in the sys.tem, pressure effects caused by pumping and
head losses, temperature effects caused by heat transfer in the
condenser and, on occasion, toxic effects caused by addition of
biocides to control fouling.
     Because of the small size of entrained organisms, and their near
neutral buoyancy, it is assumed that each organism behaves hydrody-
namically as a water parcel during passage through pumps and conden-
sers.  Organism travel  paths  are probably dissimilar, so effects may
also differ.  For instance, the position of organisms relative to
pump impellers and the  vertical distance an organisms must be raised
to reach the level of a given condenser tube in a system can result
in slightly different pressure histories.  Hence, it is necessary
to deal with averages rather  than individual organisms,,  This is
consistent with physical measurements made in circulating water
systems, such as pressure, velocity and temperature gradients which
are also described in terms of averages.  Pressure through a system
typically varies from one atmosphere to positive pressures of about
20 psig after passage through the pumps.  Negative pressures may
also be encountered.  The temperature conditions experienced by a
hypothetical organism passing through a cooling system are more
uniform than pressure.   The temperature history may be determined
by assuming a linear increase in temperature through the length
                            315

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of a condenser tube equal to the average temperature rise through
the condenser.  The effluent temperature rise can be quite variable,
depending on the amount of water circulated, and variations in plant
load.  Typical temperature rises through a condenser range from
about  0C  to  15C  with flow velocities in the condenser tubes
ranging from 1.5 to 3.0 m/sec.
     The following sections describe investigations necessary to
determine effects of entrainment on phytoplankton, zooplankton
(including entrainable benthos), and fish (including fish eggs and
larvae).  Specific sampling techniques are suggested for use at
power plants on Lake Michigan.  In addition, suggestions for labora-
tory studies are included which could be instituted if necessary
to isolate causes of entrainment effects.
     The results of these studies should be carefully evaluated
with information on lakewide populations of entrainable organisms
to determine the impact of entrainment on the lake ecosystem.

Phytoplankton
     Introduction
     The phytoplankton of Lake Michigan (described in the Micro-
biology section of this report) are susceptible to entrainment
and possible damage in cooling water systems.  Two major concerns
regarding the effects of entrainment on the phytoplankton are:
1.   Does entrainment affect the rates of mortality, growth,
     reproduction, and primary production?
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2.  Do the effects of entrainment influence lakewide populations
    of phytoplankton and other species dependent on them?

    If the answers to these questions indicate that there is a
significant effect on the ecology of the lake resulting from en-
trainment, additional questions may be asked to isolate the causes
1.  Is the effect caused by thermal, mechanical or chemical
    perturbations?
2.  Where does the effect occur, at the intake, in the plant,
    at the discharge, or in the discharge plume?
3.  What corrective measures could be employed to reduce adverse
    effects.

    Objectives
1.  Determine the effects of entrainment on phytoplankton.
2.  Determine if these effects influence local and lakewide
    phytoplankton populations.
3.  If warranted, based on answers from 1 and 2 (above) determine
    the causes of observed entrainment effects within the cooling
    system.

    Methods of Investigation
    Studies to determine the effects of entrainment on phytoplank-
ton should involve one or more basic types of observations:
1.  microscopic examination of phytoplankton,
2.  measurement of chlorophyll concentrations,
3.  measurement of rates of primary production, and
4.  observations of cell growth and division.
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     Without elaborating on specific procedure, the following re-
search outline is presented to answer basic questions concerning
phytoplankton entrainment.   Procedures involve both field and
laboratory studies.
         Effects of Plant Entrainment on Phytoplankton Mortality
            Immediate Effects
            It is extremely difficult, if not impossible to de-
termine living or dead cells from visual observation of a sample of
phytoplankton.  It is necessary therefore to rely on an indirect
physiological measurement.   Following are some measurements that
might be made:
            1.  Rate of Carbon Uptake
                Measurement of carbon uptake rates using an isotope
                of carbon ^C is a sensitive indicator of the general
                viability of the algae.   A comparison of uptake
                rates at the intake and  discharge of  a power
                plant may be used as a measure of the effects of
                plant  entrainment on the phytoplankton.

            2.  Chlorophyll measurements
                Chlorophyll "a" is a plant pigment common to all
                phytoplankton.  It is easily and accurately measured,
                and it degrades rapidly  when a phytoplanker dies.
                A comparison of the concentration of chlorophyll
                "a", and its degraded forms at the intake and
                discharge of a power plant provides another indirect
                measure of plant entrainment effects.
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           3.   Other physiological  measurements
               Other physiological-biochemical  techniques,
               such as  ATP  determination,  have  been  employed to
               assess entrainment effects  on  phytoplankton.
               These techniques  are not specific  for phytoplankton
               and are  not  acceptable  for  this  purpose without
               careful  control.
           'Long-Term Effects
               The long-term  effects of entrainment  on phytoplankton
           may be more  important to the lake  than immediate  effects.
           What happens to  a  phytoplankter several  hours  or  days
           after it has been  discharged?  Is  it  dead when it leaves
           the plant only  to  decompose 1n  the lake?   Is it  living
           when discharged  but  unable  to reproduce?   Or,  is  its
           rate of growth  and division accelerated  as a result of
           entrainment? Are  some species  affected  more drastically
           than others?
     The following are  techniques which could be  used in  an  attempt
to answer these questions:
           1.   Observation  of cultures
               Intake and  discharge water  maintained at ambient
               temperature  over  a period of several  days  provides
               one means for  answering these  questions.  Subsamples
               from such cultures may  be periodically examined for
               changes  in  species composition and abundance, chloro-
               phyll content, and carbon uptake  rates.
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2.   The effect of plant entrainment on phytoplankton
    growth, division and primary productivity
    Studies outlined under "Immediate Effects," coupled
    with No.  1 above, are also suitable for determining
    the influence of entrainment on growth, division,
    and primary productivity of the phytoplankton.
3.   The effect of plume entrainment on phytoplankton
    Although  organisms entrained in the plume do not
    pass through the plant, they may be exposed to
    turbulence, elevated temperatures, and residual
    biocides.  Comparisons of phytoplankton samples
    collected in the plume with samples obtained from
    the intake of the plant and from a reference area
    may provide insight into plume  entrainment effects.
    Studies similar to those outlined above for plant
    entrainment effects are suitable here for compara-
    tive purposes.  In addition, samples of intake and
    discharge waters may be mixed in various proportions
    to simulate the dilution of effluent water in the
    plume to observe plume entrainment effects under
    more controlled conditions.
4.   Determination of the cause of observed plant entrain-
    ment effects
    If preliminary studies of plant and plume entrain-
    ment demonstrate a significant adverse effect, the
    following studies should be initiated to isolate
    the cause:
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a.   Carbon uptake studies
    Through a series of sample manipulations and com-
    parisons it is possible to assess  the total
    effect of plant entrainment on carbon uptake
    rates and to discern the individual  effects  of
    temperature evaluation, biocide addition,
    mechanical  action and the duration of exposure
    to elevated temperatures.  Table VIII-1 summarizes
    these manipulations and the effects  measured.
b.   Phytoplankton growth and cell  division studies
    Observations of chlorophyll concentrations,  and
    species composition and abundance  on a series
    of cultures manipulated as shown in  Table VIII-1
    would yield information concerning plant effects
    on these parameters.
c.   Experiments of opportunity
    When a power plant is out of service for mainte-
    nance, the  plant often has the capability of cir-
    culating cooling water without the addition  of
    heat.  During these periods information may  be
    obtained on the mechanical effects of the cool-
    ing system  and the addition of biocides exclusive
    of thermal  effects.
d.   Preoperational studies
    A complete  assessment of entrainment effects on
    phytoplankton cannot be made prior to startup,
    but tests which simulate entrainment conditions
               321

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Table VIII - 1. Sample manipulation and comparison to assess the effects of the power plant on rate of primary
                                     production through the use of   C uptake.
                                                                              1
Effect
Measured
Total
Plant entrainment
(temp. .pressure,
pumps, turbulence)
Mechanical
CO
Ł (pumping, pressure,
turbulence, cavitation)
Temperature
(thermal elevation)
Biocide addition
Duration of exposure to
elevated temperature
Sample
Collected At
Intake
Discharge
Intake
Intake
Intake
Intake
Intake
Incubation Compared
Temperature With
Intake 	
Discharge 	
or
Intake 	
Intake 	
or
Intake 	
Intake 	
Intake 	
Sample
Col lected At
Discharge
Intake
Discharge
Intake
Intake
Discharge
and
Biocide
Intake
Incubation
Temperature
Discharge
Discharge
Intake
Discharge
Other tempera-
ture increases
above and be-
low discharge
temperature
Intake
Various elevated
temperature for
various lengths
of time
     Adapted  from Brooks  et  al.,  1974.

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                   can  be  conducted  before  final  plant  design.
                   Similar tests may be  conducted to  those  discussed
                   above for  operating  power  plants  but which  simu-
                   late expected plant  condition.

                   A  thorough  literature review  and  a series of  well-
                   designed experiments  could provide preoperational
                   information  applicable to  the  entire lake which
                   could then  be used to design  cooling systems  to
                   minimize ecological  impact.
     Methods  of  Sampling

     Each of four basic types  of observations (carbon  uptake,
chlorophyll,  microscopic examination and culturing)  should  be  made
on subsamples of a larger, well-mixed sample  to  assure  that all
measurements  are performed on  the  same  water  mass.   It  would be
beneficial  if a  subsample  could also be  taken for chemical  analysis
of plant nutrients and  toxic  substances.  Subsampling  a single
large sample maximizes  the amount  of information for interpretation
and minimizes sample  collection.
     All samples of water  for phytoplankton investigations  should
be collected in  non-metallic,  non-toxic  vessels  such as a plastic
bucket or Van Dorn bottle.  The use  of  pumps  and nets which may
damage organisms or which  are size selective  are not acceptable
for the collection of phytoplankton.  Samples should be held  in
glass or non-toxic plastic containers.   Transferring samples
through rubber or Tygon-type  tubing, which  are toxic to phytoplank-
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ton, must be avoided.
    Sarapi ing Interval
    During the initial phases of study, samples should be collected
and observations made monthly for a period of at least one year.
One sampling site such as the intake should be monitored weekly to
note sudden changes in the phytoplankton populations.   Drastic
population shifts in the weekly samples should trigger full-scale
investigations described above.
     Sam pi ing  Frequency
     During monthly  sampling, phytoplankton should be  collected
at  least  three  times  during  24-hours:   early  morning, midday,
and  late  evening.   This  schedule could  be  reduced to one  collec-
tion per  day when diuvnal patterns  for  the area have been  deter-
mined.

     Sampling  Site Selection
     The  exact point of collection is difficult to designate in
general guidelines  since nearly every power plant has a different
cooling system  design.   The  following points  in the cooling system
are  appropriate for sample collections:
1.   at the intake,  ahead of  any pumps or screens,
2.   at the point of discharge, and
3.   in the discharge  plume.
     If more detailed  investigations are necessary to determine
the  causes  of entrainment effects, additional samples may be ob-
tained within the cooling system i.e., before and after pumps and
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condensers.
     Special  Problems
     For valid comparison of two points in the cooling system, it
is imperative to collect samples from the same well-mixed water
mass as it flows through the plant.   Preliminary studies should
be conducted  with tracers to determine travel  times through the
cooling system from intake to discharge.   It is also extremely
important to  make sure that samples  collected  at the intake,  for
example, are  representative of the water  actually entering the
plant.   Stratification and nonhomogeneous conditions have often
been observed in what appear to be turbulent well-mixed waters.
The same caution would hold for the  discharge  of the plant.

Zooplankton  and Entrainable Benthos
     The zooplankton of Lake Michigan, described in another section
of this report, are susceptible to entrainment and possible damage
in cooling water systems.  Primary concerns regarding the effects
of entrainment on the zooplankton are:  1) Does entrainment affect
the rates of  mortality, growth, reproduction?   2) Do the effects
of entrainment influence lakewide populations  of zooplankton  and
other species dependent on them?  If the  answers to these questions
indicate that there is a significant effect on the zooplankton popu-
lation  of the lake resulting from entrainment, additional questions
may be  asked  to isolate the causes:
1.  Is  the effect caused by thermal, mechanical or chemical
    perturbation?
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2.  Where does the effect occur, at the intake, in the plant,
    at the discharge or in the effluent plume?
3.  What corrective measures could be employed to reduce any ad-
    verse effects?
    Objectives
1.  To determine the kinds and numbers of zooplankton entrained.
2.  To assess the effect of entrainment on survival and repro-
    duction of zooplankton.
3.  To describe the seasonal and diurnal patterns of entrainment.
4.  To relate research findings to lakewide studies.
5.  If warranted, to distinguish between mechanical and chemical
    damage and thermal effects in relation to plant design.
    Methods of Sampling
1.  Pumped samples are more desirable than net samples provided
    the pump does not damage the organisms.  A pump which will
    transfer small fish without harm is satisfactory for zoo-
    plankton and benthos.   Non-toxic material should be used
    throughout the sampling system.
    Nets used to concentrate zooplankton and benthos  from the
    pumped sample should have a maximum mesh size of 160 microns
    and should be metered, or the pumping rate should be timed
    to provide an accurate determination of the volume filtered.
2.  Samples should be taken in duplicate.   If no vertical strati-
    fication of organisms  occurs, duplicate mid-depth or integrated
    samples may be taken.
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3.  Sampling sites should be established in the forebay, immediately
    ahead of the traveling screens, and as close as possible to the
    point of discharge.   Sites  for plume entrainment studies are
    dictated by plume  characteristics.
4.  Samples should be carefully concentrated in non-toxic containers
                               »
    and inspected microscopically  for mortality and damage as soon
    as possible after collection.  (See 1  below).

    The following studies could be undertaken  at one or two sites
to answer the questions  pertaining to  the  entire lake,  or major
regions.
1.  Special studies  should be  conducted to establish criteria
    for damage and to examine  the relationships of motility,
    vital  dye uptake, or other  indices to  long-term effects.
2.  Time-temperature studies should be conducted to establish
    thermal tolerances  of important species and to permit an
    estimate of plume entrainment effects.
3.  Zooplankton and  benthos  entrained  in the plant and/or the
    plume may experience a non-lethal  thermal  shock that will
    adversely affect normal  reproduction.   Special  studies should
    be conducted in  which zooplankton  and  benthos are exposed to
    a thermal regime through time for  observations of growth and
    reproduction.
4.  If biocides are  added to the cooling water, special studies
    should evaluate  effects  on  zooplankton and benthos.
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     Sampling Frequency and Interval
     Samples should be taken in the forebay and at the discharge
during a 24-hour period at least monthly.  Duplicate samples
should be taken every 3 to 4 hours during the 24-hour survey.
Fish
     Introduction
     Entrainment of fish, fish eggs, and larvae has been observed
in once-through cooling systems of plants located on the Lake Mich-
igan shoreline, but the species and numbers of these organisms and
their fate have been poorly documented.  The potential for damage
to the lake fish populations by entrainment depends on the numbers
of organisms that pass through the condenser system and on the
conditions experienced during passage.   Fish, fish eggs, and larvae
also can be entrained directly in the effluent plume from the
receiving water when the effluent is discharged into the lake,
especially at plants where diffuser systems are used to enhance
mixing for rapid temperature reduction.
     Objecti ves
          Plant Entrainment
          1.  Determine the species and numbers of fish, fish
              eggs, and larvae drawn into and discharged from
              cooling systems using Lake Michigan water.
          2.  Determine the immediate and delayed effects of
              cooling system passage on these organisms.
          Plume Entrainment
          1.  Determine the species and numbers of fish, fish
              eggs, and larvae entrained directly into the
              discharge plume from the  receiving water.
          2.  Determine the immediate and delayed effects of plume
              entrainment on these organisms.
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Questions to be Answered
     Plant Entrainment
     1.  What species  and  numbers  of  non-screenable fish,  fish  eggs,
         and larvae are drawn into and  discharged from cooling  water
         systems?
     2.  Are there statistically significant differences in the
         species and numbers of non-screenable fish, fish  eggs, and
         larvae drawn  into cooling water systems on a diurnal,
         seasonal and  annual basis?
     3.  Assuming 100% mortality of the fish, fish eggs and larvae
         that are entrained, is it reasonable to expect that this
         loss in itself,  or when added  to the other losses resulting
         from cooling  water use will  significantly affect  fish  popula-
         tions?  If so, the following questions should be  answered to
         more clearly  identify the specific causes of the  entrained
         losses.
     4.  Is there a statistically significant difference between the
         numbers of viable, non-screenable fish, fish eggs, and larvae
         drawn into a  power plant and the numbers discharged from the
         cooling system?
     5.  Is there a statistically significant correlation  between
         densities of  non-screenable  fish, fish eggs, and  larvae in
         the area of the  lake near the  cooling system intake and the
         species and numbers in the cooling water drawn into the
         plant?
     6.  Will eggs that survive plant passage be able to complete
         development;  will fish and fish larvae that survive plant
         passage be mobile and able to  locate and capture  food
         effectively?
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7.  Will fish and fish larvae surviving plant passage be more
    susceptible to capture by predators concentrated in or near
    the discharge plume?
3.  Will the simple physical  transport of undamaged fish, fish
    eggs, and larvae from the intake area into the discharge plume
    reduce survival?
9.  If the answers to the above questions confirm the potential
    for significant detrimental effect on lakewide fish populations
    caused by entrainment, to what extent are the following factors
    responsible:  pressure changes; elevated temperatures, changes
    in gas saturation; chlorination; collision with screens, pump
    impellers and other internal  surfaces of the cooling system;
    and shear forces created  by turbulence?
Plume Entrainment
1.  What kinds and numbers of fish, fish eggs, and larvae are en-
    trained directly into the discharge plume from the receiving
    water?
2.  What are the diurnal, seasonal, and annual discharge entrain-
    ment patterns?
3.  What percentages, if any, of the entrained fish, fish eggs,
    and larvae are killed because of the conditions encountered?
4.  If the answers to questions 1 - 3 above demonstrate a signi-
    ficant detrimental effect on the fish populations caused
    by plume entrainment, to  what extent are each of the following
    factors responsible:  gas saturation; chlorination; shear
    forces created by turbulence; probable decrease in ability to
    avoid predators concentrated in or near the plume; displacement^
    of entrained organisms from one habitat to a second, perhaps
                        330

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     less favorable habitat?
Methods of Investigation and  Sampling
     Plant Entralnment
          Sampling with a Pump  Sampling  System
     A pump sampling system is  recommended  as  the  primary method
for determining species and number  of  non-screenable fish, fish eggs,
and larvae of each species passing  through  plant cooling systems.   A
pump sampling system is preferred  because a standardized system can
be built that can be used at  most  if not all  plants, thereby providing
a basis for comparability of  data  collected among  plants.  Pumped
systems also are easier to automate than systems in  which sampling
is done with nets suspended directly in  the mainstream of the cooling
water flow.  (An automated pump sampling system is under develop-
ment at the Great Lakes Fishery Laboratory.)
     Continuous pumped sampling is  recommended as  the primary method
for determining species and numbers of fish,  fish  eggs, and larvae
of each species entrained and passing  through  power  plant cooling
systems, because (a) the numbers of these organisms, even in areas
known to be good spawning and nursery  areas,  are typically low, and
(b) their distribution in time  and  space is usually  either changing
rapidly or patchy as a result of natural conditions.  Therefore,
adequate representation of these organisms  can only  be obtained
with continuous sampling.
     The actual volume of water to  be  pumped to provide an adequate
sample is dependent on the densities of fish,  fish eggs, and larvae
in the water surrounding the  cooling system intake structure.  If the
maximum recorded density of 6.4 alewife larvae per cubic meter at the
                             331

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Cook Plant intake on July 20, 1973 (see Wells, 1973) is taken
as an example, a continuous pumping rate of 0.75 cubic meters per
minute or about 1,090 cubic meters per day would have to be main-
tained to obtain a sample of approximately 7,000 larvae.  By the
same logic, reducing the larval  density in the influent water by
two orders of  magnitude (to 0.064 per cubic meter) would reduce the
number captured .to about 70 per day — probably still an adequate number
from which to estimate the daily larval entrainment rate.  However,
reduction of larval density by 3 orders of magnitude (to 0.0064 per
cubic meter) would require a higher pumping rate to insure adequate
representation of this species in the sample.
     Alewife larvae are probably more abundant in the lake than those
of any other species of fish, e.g. perch never exceeded 0.071 per
cubic meter and most samples had less than 0.047 perch larvae per
cubic meter (Wells, 1973).   Smelt were even less abundant (0.038 per
cubic meter)  than perch, and few if any larvae of other important
species were captured at all.  The available data, therefore, indicate
that continuous sampling at a pumping rate of at least 0.75 m^/min.
would be needed to detect the entrainment of these species.
Sampling Location
Pump intake ports of the sampling system should be located:
1.  Immediately behind the  traveling screens, if possible; other-
    wise, immediately ahead of the traveling screens.
2.  At a suitable point in  the discharge system.
3.  One sampling port should be  located near the surface, one
    near the bottom, and one at  mid-depth.  If uniform mixing can
                            332

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     be demonstrated,  one sampling depth may suffice.
Sampling Frequency and Duration
Sample continuously for one year to determine the kinds  and numbers
of non-screenable fish, fish eggs, and larvae that pass  through the
plant; sample for at least one additional  year during  periods of
peak entrainment to provide a measure of year-to-year  variability.
     The 24-hour sampling day should be divided into four parts
corresponding to the four major  diel periods (dawn, daylight, dusk,
darkness) and a single composite sample should be obtained daily
for each of these periods.
Sample Processing
1.  Preserve each sample in 10 percent formalin.   (Note:  It is not
    necessarily intended that every sample collected under this
    continuous sampling routine  be examined and analyzed; rather
    the sampling objectives, the sample variance, and  the required
    level of precision will dictate which of the  preserved samples
    are to be subjected to the following additional processing).
2.  Sort preserved fish by species and by developmental  state
    (prolarvae, larvae, post-larvae, or juvenile) within species,
    enumerate each subgroup separately, and measure an adequate
    sample (total length in mm).
3.  Sort eggs by size group or species; measure diameters of an
    adequate sample in each group.
             Sampling with Anchored Plankton Nets
    These experiments are designed to provide data for comparison
of sampling efficiency of pumped and non-pumped sampling methods
and to provide data on the number of non-screenable, live and dead
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fish, fish eggs, and larvae that are drawn into and discharged from
the plant.  Note:  The need for estimates of in-plant mortality of
these non-screenable fish, fish eggs, and larvae depends on the
answers obtained to questions 1 - 3 above for Plant Entrainment.
     Sample Location
     Suspend one plankton net immediately downstream from each of
the intake ports of the pumped sampling system, in the traveling
screen well or at another plant location upstream from the con-
densers, where comparative studies can be made.
     Sampling Gear
     A conventional 1/2 meter oceanographic plankton net with a
maximum mesh  aperture  of 351 microns and with a flow meter in-
stalled in the net opening, and a large "non-flow through" collecting
chamber in .the apex is the gear of choice.
     Sampling Frequency and Duration
     Collect net and pump samples simultaneously for as long as
necessary to permit comparison of the effectiveness of the two
methods and to provide the needed data on in-plant mortality of
non-screenable fish, fish eggs, and larvae.  Note:  It will be
necessary to determine the filtering efficiency of the suspended
nets by comparing the flow rate recorded by the net flow-meter for
the complete net (net frame, flow-meter, net bag, and collecting
vessel) fished in the normal sampling location, with the flow rate
recorded by the net flow-meter after the net bag and collecting
vessel have been removed.  Flow rates obtained under the latter
conditions also will provide information needed to expand the
catches obtained by the pump sampling system.
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Sampling Process
1.   Sort eggs by size group or species,  measure diameters of
    an adequate sample in each group,  and  record the condition of
                                         f
    each egg (live or dead).
2.   Preserve the entire catch  in  10  percent  formalin after live
    examination.
3.   Sort fish by species and  by developmental  state (prolarvae,
    larvae,  post-larvae, or juvenile)  within species,  and enumerate
    each subgroup separately;  record the condition of  each fish
    (1ive or dead).
4.   Measure  an adequate sample (total  length in mm) of each
    subgroup.
5.   Preserve the entire catch  in  10  percent  formalin after live
    examination.
6.   Methods  should be developed to permit  rapid distinction
    (under field conditions)  between live  and  dead fish,  fish  eggs
    and  larvae, and  between live, damaged  individuals  and those
    that have suffered subtle  but irreversible damage  that will
    directly or indirectly cause  their death,  or otherwise prevent
    them from completing their normal  life cycle.   Vital  staining
    techniques currently under development may prove helpful in
    making these determinations.
         Plume Entrainment
         Determine the species and numbers of  fish and fish eggs
    and  larvae entrained directly into the discharge plume, and the
    effects  of the entrainment on these  organisms  by sampling  with
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towed plankton nets in and around the discharge plume.
     Sampling Locations
     Collect samples simultaneously at the discharge, in the
plume, and in unheated waters adjacent to the plume.  If a physical
plume model can be developed to show the amount of receiving water
that is mixed with the heated effluent at various points along the
longitudinal axis of the plume, only information on the density of
the entrainable fish, fish eggs, and larvae in the receiving waters
adjacent to the plume is needed to estimate the kinds and numbers
of these organisms that may be entrained.  Sampling at intervals
on the longitudinal axis of the plume within discrete temperature
isotherms permits evaluation of the condition of fish and fish eggs
found there, so their condition can be related to the effects of
plant and plume entrainment.
     Sample Gear
     The gear of choice is a conventional one meter, 351 micron
mesh, oceanographic plankton net with a flow meter installed in
the net opening and a large non-flow through collecting chamber
installed in the apex of the net.   When towing these nets at the
appropriate speed to capture small fish (maximum of about 4 mph,
true net-speed through the water)  a steel towing cable (about 1/8
inch) and a heavy metal "net depressor" (about 45 pounds) will
be required.
     Sampling Frequency and Duration
     No estimates of sampling frequency can be made until reliable
descriptions are obtained of the species and numbers of fish,
                           336

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fish eggs and larvae entrained fr,om the receiving water.
     Sampling Process
     See above section for processing live fish, fish eggs, and
larvae on page 335.
                    Priority Research
     The research priorities listed below are designed to provide
answers to questions concerning the local and lakewide effects of
entrapment and entrainment at cooling water intakes and discharges
on the biota of the lake.
1.  What are the effects of entrainment on the phytoplankton
    and zooplankton populations of Lake Michigan?
2.  What are the effects of the entrainment of fish and fish
    eggs and the entrapment of fish on the Lake Michigan
    fishery?

    An adequate answer to  each of these questions clearly demands
a rather complete understanding of the spatial and temporal aspects
of the populatio.n dynamics of Lake Michigan phytoplankton, zoo-
plankton, and fish.  Distinguishing the effects of entrainment and
entrapment on the biota of the lake from natural background
variation will be difficult and expensive but will be necessary
if we are to predict the effects of cooling water use.
     The following is a list of priority research topics of a
more specific nature.  Priority values have been ranked according
to the following scheme:
                         337

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1.   - highest priority, consistent with achieving primary goals
     of the Panel ,
2.   - high priority studies supporting priority 1 items,
3.   - intermediate priority, but ultimately providing support
     to priority  1,
4.   - low priority supporting other programs but not of critical
     importance in itself,
5.   - deferred priority of a general supporting nature.

Categorical values may be interpreted in the following way:

     Answers to these questions should be developed:

     1.   - as soon as possible using available data,

     2.   - using data currently being collected,
     3.   - by means of individual research projects  which
            are not now underway.
A.   Entrapment
     1.   To evaluate the data on the numbers of fish currently
          entrapped at Lake Michigan cooling water intakes and
                                338

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          determine if this  loss is detrimental  to the local
          and lakewide fish  populations.

          Priority 1,  Category 1 and 2

     2.    To evaluate  fish entrapment data  to determine which
          of the existing  intake designs  entrap  the fewest
          fish.

          Priority 2,  Category 1 and 2

     3.    To investigate alternate  intake designs  of fish
          diversion devices  to minimize  fish  entrapment.
          Priority 2,  Category 3

B.    Entrainment

     1.    To evaluate  existing data concerning the effects of
          plant  and plume  entrainment on  the  phytoplankton,
          zooplankton  and  fish populations  of Lake Michigan.
          The following sequence should  be  followed:
          a.  Determine the  species and  numbers  of each species
              entrained.

          b.  Determine percentage  mortalities resulting  from
              entrainment, based on available data.  Where
              data are lacking for  specific groups of organisms,
                                339

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         assume 100 percent mortality.
     c.  Gather existing data on concentrations of en-
         trainable organisms in representative zone around
         the lake, and estimate the size of the local  and
         lakewide populations.

     d.  Obtain data on flow rates of cooling water through
         selected plants within these zones and the volumes
         of water entrained by  the effluent plume within
         the l.OC isotherm.
     e.  Calculate percentage loss of the local and lakewide
         population of each organism group within the
         representative zone.

     f.  Determine whether these losses will  significantly
         affect the local  and lakewide populations of  these
         organisms and what effects will be manifest in the
         overall Lake Michigan  ecosystem.
     Priority 1, Category 1 and 2
2.   If significant data gaps are found or if adverse  effects
     are predicted from the analyses outlined above, proceed
     with the monitoring program suggested.

     Priority 3, Category 3
                          340

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                  Literature Cited
Brooks, A.S., R.A. Smith, and L.D.  Jensen.   1974
     Phytoplankton and Primary Productivity.  In:   Environ-
     mental  responses to thermal  discharges from the
     Indian  River Station, Indian River,  Delaware.   Ed. by
     L.D. Jensen.  Rept. No.  12.   Cooling Water Discharge
     Research Project (RP-49).  The Johns Hopkins  Univ.
     205 pp.

Jensen, L.D. 1974.  Entrainment and Intake  Screening
     Proc. of the Second Entrainment and  Intake Screening
     Workshop,,   Report No. 15.  The Johns Hopkins  Univ.
     Cooling Water Research Project.  Electric Power
     Research Institute, Palo Alto, California.  347 pp.

Lake Michigan Cooling Water Intake  Technical Committee, 1973,
     Lake Michigan Intakes:  Report on the  best technology
     available.   U.S. EPA, Region V, Chicago.   152  pp.

Sharma, R.K. 1973.  Fish Protection At Water Diversion  and
     Intakes:  A bibliography of  published  and unpublished
     references.  ANL/ESP-1.   Argonne National Laboratory,
     Argonne, Illinois.   33 pp.

Sonnichsen,  J.C., Jr., B.W. Bentley, G.F. Bailey and
     R.E. Nakatani, 1973.
     A Review of Thermal Power Plant Intake Structure
     Designs and Related Environmental Considerations.
     HEDL-TME 73-24 UC-12.  Hanford Engineering Development
     Lab., Richland, Wash.  93 pp.

U.S. Environmental Protection Agency. 1973.
     Development Document for Proposed Best Technology
     Available  for Minimizing Adverse Environmental  Impact
     of Cooling  Water Intake  Structures.   EPA  440/1-74/015.
     175 pp.

Wells, L. 1973.   Distribution of  fish fry in nearshore
     waters  of  southeastern and east-central Lake  Michigan,
     May - August 1972.   Great Lakes Fishery Laboratory.
     Ann Arbor,  Michigan Administrative Report.  (processed)
     24 pp.
                        341

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               SECTION IX



RADIOECOLOGICAL CONSIDERATIONS RELATED  TO



            COOLING WATER  USE

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Section IX.  RADIOECOLOGICAL CONSIDERATIONS RELATED TO COOLING
             WATER USE

                      TABLE OF CONTENTS

 General Discussion of Problem .   	 345
 Conclusion	   . 346
 Priority Effort  	 347
                           3.44

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Section IX.   RADIOECOLOGICAL CONSIDERATIONS RELATED TO COOLING
                            WATER USE

                 General  Discussion of Problem
     Within  the scope of  the charge to the Lake Michigan Cooling
Water Studies Panel,  radioecological  considerations are limited
to the area  of the cooling water discharge where temperature and
other effluents remain measurably higher than ambient levels.
The effect of radiation from both internal and external sources
on a wide variety of  aquatic biota have been examined in consider-
able detail  in the laboratory,  and to  a lesser extent in the field.
The objective of much of  this work was to establish the lethal
radiation dose (LD50) for various aquatic organisms.  The effects
of radiation on reproductive capacity, spawning behavior, and life-
span have also been investigated in laboratory and field experiments.
     It is clear that radiation does  effect some biological  para-
meters in adverse manner  although the  one of outstanding concern
is reproduction.  These effects increase as a function of increased
temperature.  Radiation should  be regarded as a biological  stress
similar to temperature variations from the norm, chemical toxicants,
and disease  states except that  long-term and cumulative effects
must be considered.  Under the  "as low as practicable" concept for
routine releases from nuclear operations, it is doubtful if biota
resident immediately  in the discharge  will receive an additional
radiation dose equal  to natural background (about 125 mrad/year).
Hence, radiation per  se will be a minor contributing factor rather
than a primary causative  factor in the biological effect of
                            345

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discharges from once-through cooling of nuclear power stations.
However, in order that observed biological effects (if there are
such) in the outfall region not be falsely attributed to radia-
tion, or conversely to another causative agent if radiation levels
are high, the following measures are recommended:
     1.  Radiation exposure levels to aquatic biota should be
         calculated on the basis of radiological monitoring data
         at specific nuclear plant sites.
     2.  Radionuclide analyses should be performed at least
         seasonally on representative biota collected in the dis-
         charge region and the internal dose from such analysis
                                     i
         should be calculated for these same biota.  This recom-
         mendation is probably fulfilled by most current radiologi-
         cal monitoring programs.
     3.  Deploy clams or other suitable shellfish as biological
         accumulators and indicators of maximal radionuclide up-
         take and exposure; TLD dosimeters should be employed along
         with these biological probes.   Taken together, these
         devices (Clams and TLD's) should provide a reasonable
         estimate of the upper limit of radiation exposure ex-
         perience by resident biota at  any given site.
                            Conclusion
     In summary, the subcommittee feels that biological effects due
to radiation under routine operation of nuclear power plants will
be minimal, and in all probability unmeasurable.   For the sake of
completeness, however, it is felt that  a quantitative fix on
radiation levels should be obtained at  various plant sites to test
                            346

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the validity of this prediction.
                         Priority Effort

     In light of limitations  of the interest of the Panel to radio-
ecological  aspects of the cooling water alone, and to the findings
of the author, that biological  effects  due to radiation during
routine operation of nuclear  plants will be minimal, no research
priorities  have been assigned.
     The author has recommended the following effort in order to
insure that these limitations may be satisfied.  Obviously no
priority value or categorization  is necessary.
     A priority effort should be  made to establish whether data on
radioactivity from present monitoring programs is adequate to
reliably predict the dose to  the  biota  entrained or otherwise in-
teracting with thermal  discharge.  Field measurements of radiation
exposure are a necessary part of  this effort.
                            347

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                APPENDIX
 Comments of Members and Participants
of the Panel related to Report Number 1

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                               Appendix

                 Comments of Members and Participants

               of the Panel related to Report Number 1


During the course of preparation of Report Number 1, a number of comment
periods were designated by the Panel.  On June 6, 1975, the final draft
was forwarded to members and active participants of the Panel (those
individuals who had commented on the previous draft report) for a final
comment period.  At the July 8, 1975 meeting, comments were distributed to
authors of various sections of the report.  Following discussion, authors
agreed to incorporate comments where possible and prepare a written response
to those comments which they did not choose to incorporate.

The following comments and written replies are the product of this endeavor:


                   Comments related to Section III

                 Measurement of the Effects of Cooling

                   Water Use on Physical  Parameters


Comment of Jacob Verduin, Southern Illinois University, Carbondale, Illinois:

There is a great deal of data available concerning the chemical  changes associated
with once-through cooling.  The data show that the chemical changes are small.
No attempt has been made to summarize, review, or reference such data in the
report.

Numerous studies have been made concerning the present, and projected level
of thermal loading in Lake Michigan.  These contain estimates of the temperature
increment that can be associated with present and projected (year 2000) thermal
injections.  Such studies have not been reviewed, or referenced in the report.

Pertinent information on lake currents near the shore has been ignored.  Bellaire
made a study of currents in Lake Michigan (Publ. No. 10, Great Lakes Research
Division, University of Michigan, Ann Arbor, 1963) that can be used to assign
approximate values to alongshore currents.  He portrays a net northward flow
parallel to the west shore of about 0.3 miles per hour.  Such a current pattern
will move water from the Chicago area to the Milwaukee area in about 20 days.
Consequently, any data obtained in the Milwaukee area probably reflect a strong
influence of contributions from the Chicago area.

During 1973 six current meters were maintained near Zion, Illinois, by Hydrocon,
Inc.  These records confirm the net northward flow described by Bellaire, and
show that periods of near-zero current flow usually last for only a few hours.
Current reversals occur at 2-3 day intervals, there is an average northward
flow of 4.6 miles per day, an average southward flow of 2.2 miles per day,
yielding a net northward flow of about 2.4 miles per day.
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Such currents have a profound influence on the dispersal  of thermal  (and other)
injections, and they have a distinct bearing on proposed monitoring programs.
For example:  A "Reference" station located 8 miles north of a point of injection
will be occupied by water that has moved up from the injection point within the
previous few days.  All  direct evidence of a thermal injection will  have been
obliterated, but the biota sampled will not be "Reference" biota but will
contain individuals that have recently passed through a thermal plume area.

There are many other pertinent data that should be referenced and evaluted if
the report were to comply with the initial charge (page 2) to review background
information	relating to thermal discharges....

A written reply to these comments was not received.
                    Comments related to Section IV

                    Measurement of the Effects of

               Cooling Water Use on Chemical  Parameters
Comment of J.J. Ney, Wisconsin Electrict Power Company, Milwaukee, Wisconsin:

Operational Monitoring (pp. 114-115) presents an unjustifiably intense intake-
discharge monitoring program.   Studies at Lake Michigan power plants have
demonstrated that concentration of nutrient and general water quality parameters
are not perceptibly affected by condenser passage.   However, concentrations do
change on a seasonal basis.  The parameters included in weekly measurement
(p. 115) need be measured only seasonally.

A written reply to this comment was not received.
                    Comments related to Section V

                    Measurement of the effects of

                Cooling Water Use on Primary Producer

                       and Consumer Communities


Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

The field study guides described in this section are based to a large extend  on
two assumptions.  It is assumed that residence time of plankton is sufficiently
long that plume populations can be defined and thermal effects (through plume
vs. reference area comparisons) isolated.   A second, related assumption is that
thermal input induces first-order perturbation such that change in lake populations
can be traced to heat as the causative agent.  Evidence to data from numerous
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studies tends to negate these assumptions.  Plume entrainment time is generally
limited to a few hours.  Nutrient input from agricultural runoff and point
sources is the primary agent of historical change in Lake Michigan planktonic
communities.

While the 16 mile-transect sampling program in the various biological provinces
as detailed for both phytoplankton and zooplankton assemblages should enable
documentation of changes over time, it does not in itself permit determination
of the sources of change.  The site-specific program utilizing as many as 64
sampling stations at all depths is incapable of defining heat-induced changes
to the transient populations.

A more constructive approach, partially outlined in this section, involves the
development of predictive models of the reaction of the plankton communities
to thermal addition.  Input would include-quantification of plumes, entrainment
time and characterization (seasonal composition and abundance) of nearshore
planktons assemblages.  Short-term and repeated exposure bioassays and in-situ
productivity experiments should be employed to determine thermal tolerance and
response.  Ultimately, models could be tested by field observation and simulation
techniques.  Like other studies described in this section, some of the necessary
methodology remains to be developed.  However, the total effort should be
considerably less intensive and more fruitful since general models could be
adapted to site-specific situations.

It is of interest that this approach is being used to define water quality
standards for nekton, which are capable of establishing resident discharge-area
populations.  The fact that planktonic populations are incapable of such residency
further recommends developnent of the modeling approach to assess thermal effects.

Written reply of E.F. Stoermer, University of Michigan, Ann Arbor, Michigan:

The possibility of greater reliance on modeling was discussed at considerable
length by this subcommittee.  Two major points became obvious from these
discussions:  (1) There is a great deal of uncertainty if state of the art
simulation models can deal with the time transients possible in the near-shore
zone of Lake Michigan; and (2) Data requirements for viable model would certainly
be no less stringent than those proposed.  It is probably desirable to work
toward developing realistic ecological models of the scale Dr. Mey envisions,
but it should be recognized that this would require considerable effort and
resources beyond those presently employed by contractors engaged in site studies
on Lake Michigan.

Comment of R.P. Herbst, The University of Wisconsin, Waukesha, Wisconsin:

General Comments:

These items have not been adequately addressed in the Microbiology Section.

     1.  The study area and areas of concentration should be indicated along
         with a rationale for those limits.

         a.  Extensive and statistically sound use should be made of reference
             locations and times.

     2.  Collection of data on each environmental parameter should be justified.
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Specific Comments:

Page 137 - Sub-paragraphs numbered 2 and 3 of. Measurements which should be
made.„„,,  Rationale is not provided nor study design!   Again justification is
needed as to why ten stations are required when a minimum of two will  be
sufficient.  Why are depth samples measured when the plume floats?  Depth
sampling will provide information on light penetration but why is this necessary?
What is the justification for estimating nitrogen fixation?  I cannot  identify
any rationale as to why this information would serve to be useful or how it
would be applied to thermal  discharges with the possible exception of  baseline
academic information.  I think some rationale should be presented as to its use
and validity for some environmental parameter affected by thermal discharges.
Is it to be a metabolic indicator of the blue-green algal populations„ or the
amount of nitrate added to Lake Michigan from this source compared to  sewage,
industrials agricultural, and natural inflows such as  rivers and rainfalls etc.?

Page 138 - First and second paragraphs on the page beginnings "In addition....
There is very little justification for doing any of this work as well  as more
speculative statements without support.  For instance  why should there be an array
of stations to "16 statute miles from shore" if the thermal discharge  never
reaches this far and "significant changes" in the algal populations occur over
very short distances?!" It is further stated that these stations could serve as a
possible monitor of whole lake effects.  I see no way  that this could  be possible
especially when it was stated earlier that the open lake's populations are
completely different!  Therefore9 how could whole lake effects be determined from
this sampling pattern?  This is better attempted from  the experimental procedures
mentioned in the following paragraphs although there are severe limitations.  In
additions the Statistical Analysis Section also presents the procedures for
detecting variability as well as differences between locations and neither implies
nor suggests a sampling scheme as indicated here.  If  the authors provide a
statistical design for this "16 mile transect" perhaps its purposes etc. can be
ascertained.  If again this is a "gut feeling" or a "nice bit of information" it
should be so stated.  If it can be justified that this will indeed provide some
"monitor of possible whole lake effects" it should be  so indicated.

In summation of my comments, I think it would be especially important  for this
section to have an economic assessment.  It would be very noteworthy if extended
to detail the information considered essential for thermal discharges  and that
which is of academic interest.  This would enable a more precise evaluation of
suggested studies and techniques for not only the writers but potential users.
A great deal of the material in the Microbiology Sections while necessarily being
the opinions of the authors and not the consensus of the Panel, would  not answer
with anymore validity9 statistical designs of a more basic nature to assess effects
of thermal discharges.  Further, when costs for redundant data are examined, the
financial consequences to taxpayers via grants, etc. as well as potential users
are extremely high and might better be channeled into  special studies  of a nature
which would delineate cause, effect and possible redesign.

Finally, I would like to compliment both Dr. Stoermer  and Dr. Neese for a fine
effort.  Having actively participated in the many Panel discussions regarding the
report and their section it becomes only too apparent  that it is easy  to criticize
but that not enough recognition is given to the good parts.  All aspects of this
section cannot be completely satisfactory to everyone  nor will they necessarily
answer with any finality many of the questions asked.   I think both men have
attempted to provide the necessary background, etc. for this section.   With only
a few exceptions they have done an excellent job.
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A written reply to these comments was not received.


Comment of Roy F. Heberger. U.S. Fish and Wildlife Service, Ann Arbor.
Michigan:

In the current draft, most of my technical comments were adopted.   I  remain
firmly opposed to use of the trophic level references.  They are confusing and
often misleading.  The footnote on page 146 is, in my opinion, inadequate with
regard to this problem.  The only purpose the footnote served was  that  of
avoiding necessary changes in the text.

A written reply to this comment was not received.


Comment of Jacob Verduin, Southern Illinois University, Carbondale, Illinois:

The recommendations concerning investigation of phytoplankton are  unrealistic.
The intensity of sampling number of depth intervals, number of stations,  and
biochemical analyses recommended (chlorophyll, organic nitrogen, organic  carbon,
nutrient uptake rates, nitrogen fixation rates, etc.) are not justified by any
explanation  of the goal such analyses are designed to achieve.  It seems, rather,
that most of the phytoplankton researches that have appeared in the literature
during the past twenty years are here recommended for a monitoring program at
an unprecedented level of sampling intensity in the hope that such a  program may
reveal some evidence of thermal impacts on the communities.

The program does not hold real promise of such a result.  The postulated  effects
of thermal injection are:

     a.  injury by superoptimal temperature

     b.  stimulation of metabolism by increased temperature within the  range
         of tolerance

     c.  shift in major component species from desirable to nuisance  forms

However, none of these effects are specific for thermal injuections.

Injury to aquatic organisms has been a demonstrated effect of chlorination, and
it is well known that chlorination of sewage effluents is required by Health
Department regulations.  Moreover, the currents along the west shore  of
Lake Michigan are of such magnitude and direction that waters from the  Chicago
area are distributed along the shore all the way to Milwaukee.  If one  were to
establish a detectable injury to phytoplankton between Waukegan and Milwaukee, how
would one distinguish between damage from chlorinated sewage effluents  and damage
from postulated thermal injury?

Stimulation of phytoplankton metabolism is a well-known effect of nutrient enrich-
ment.  Sewage outfalls, storm runoff from lawns and fields, provide such  injections.
If one were to establish a detectable increase in phytoplankton metabolism between
Waukegan and Milwaukee, how would one distinguish between the stimulus  derived
from nutrient enrichment and that derived from the postulated thermal stimulus?

The trickling filters of sewage treatment plants are heavily populated  with blue-
green algae, which constantly break away from the filter and enter the  lake as a
potential innoculum of nuisance algae.  If one were to detect an increase in


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nuisance algae between Waukegan and Milwaukee how would one distinguish between
the importance of this source and the postulated influence of thermal impacts?

There is no  evidence in the report that the serious problem of separating such
effects is recognized.  There certainly are no recommendations which will serve
to isolate these effects so that a clear conclusion can be reached as to which
source is responsible for a particular kind of community perturbation.  The
presence of sewage outfalls and the plant nutrient injections from the watershed
must have an order of magnitude larger impact on lake ecology than the thermal
injections of power plants on the lake.

Finally, there is an abundant literature concerning the response of aquatic (and
other) organisms to temperature change.  This literature makes it possible to
evaluate the metabolic changes that are likely to occur in a thermal plume.
Analyses of this kind have been made and are available, both in the scientific
literatures, and in testimony presented at operating permit hearings.  They reveal
that phytoplankton and zooplankton passing through a plume in Lake Michigan are
likely to experience a 15 percent increase in their metabolic rate for a period
of about two hours, after which they will return to ambient temperatures and
normal metabolic rates.   There is  no  evidence that such an experience has any
prolonged or deleterious effects.  Moreover, photosynthetic and respiratory rates
have been measured within thermal plume areas under normal plant operation.  These
studies confirm the correctness of the predictions based on temperature coefficients
gleaned from the literature.  The failure to reference any of this literature, and
to summarize and evaluate the predictions concerning metabolic rates in thermal
plumes which have been derived from it, represents noncompliance with the first
paragraph of the charge to the panel,  as quoted on page 2 of this report.

Written reply of E.F. Stoermer, University of Michigan, Ann Arbor, Michigan:

It would appear to me that the substance of Dr. Verduin's extended comment is
that anthropogenic effects on the Lake Michigan ecosystem are multiple, complex,
and synergistic.  It would appear to me that this is precisely why a reasonably
comprehensive data collection program is needed to partition thermal effects.  It
is, unfortunately, a fact of life that Lake Michigan is a highly perturbed system.
At this time it is entirely futile and unproductive to speculate what might be if
other environmental insults did not exist.   What is needed are studies which will
evaluate the impact of thermal  loadings on the real world Lake Michigan system
as it exists.  I agree with Dr. Verduin that it may eventually be necessary to
extend studies to include synergisms,  which presently appear improbable, such as
the imput from trickling filters, but I do not think it possible to anticipate all
possible effects in the  present document.
                     Comments  related  to  Section  VII
                      Measurement of the  Effects  of

                    Cooling  Water Use on  the Fishery


1.   Comment of J.H.  Hughes,  Commonwealth  Edison,  Chicago,  Illinois:

    As per your July 1,  1975S  request to  Mr.  Howe,  we  have rewritten  my
    June 25, 1975,  letter concerned  with  the Fisheries Section  of the Panel


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    Report in order to meet your needs for the final report.  Commonwealth
    Edison requests that this section of the Report be deleted unless
    Mr. Edsall and Mr. Yokum reply to our January 16, 1975, comments as per the
    Minutes of the October 1, 1974, meeting.

    Written reply of T.A. Edsall. U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We responded verbally to the comments in your letter of January 16, 1975,
    (as directed by the Panel on October 1, 1974) at a meeting held in the
    Region V EPA office (Mr. Howe represented your company at that meeting).
    We were advised by Mr. Bremer on July 1, 1975, that you subsequently
    requested a  written reply to your letter of January 16, 1975, and we
    provided that reply on July 2, 1975.


2.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    Unless they have already done so, they should also reply to comments of
    Dr. Verduin, Dr. Ney and Mr. Patriarche.  The authors rebuttal to these
    comments should subsequently be appended to the report along with the
    comments.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service. Ann Arbor,
    Michigan:

    We responded verbally to Mr. Patriarche who seemed satisfied with our
    reply and prepared a written response to Dr. Ney; we have not been advised
    that Dr. Verduin requested a written response and so did not prepare one.


3.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    Because we believe based on past experience that no substantial changes
    will be made in the Fisheries Section, we also request that the Qualifying
    Statement (page iii)be identified. This modification should emphasize that
    the various Sections reflect primarily the opinion of the authors and are not
    a result of Panel  consensus and do not constitute Panel  approval.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We believe the comment regarding our unwillingness to make substantial
    changes in the Fisheries Section is untrue.  We invite the reader to
    examine the 10/1/73, 2/22/74, 5/23/74, 10/29/74 drafts of Fisheries Section
    and to compare these earlier versions with the most recent one, which is being
    readied for publication.  For example,  as the result of discussions with
    Mr. Howe (and others), we:

         1.  updated and increased (nearly doubled the length of) the Literature
             Cited Section of the Fisheries portion of the Report;

         2.  altered the text of the Report relating to the tagging program to
             make it clear that mark and recapture studies are not recommended
             for use in the estimation of population size;

         3.  changed the performance criterion that asked the field sampling


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             program be adequate to  detect  differences  of 5% (at  a  =  0.05)
             to one adequate  to  detect true differences of only 20% (at  a =  0.05);

         4.   added the Qualifying Statement on  pages  256-257;

         5.   revised, reordered, and "nested" our research priorities;

         6.   expanded and revised the Introduction;

         7.   added Figures VII-1 and 2 to provide a basis for bridging the
             gap between the  intake  and discharge effects sections  of this
             report;

         8.   we did not attempt  to present  a complete review of the literature
             regarding cooling water use effects  but  rather selected  for
             presentation only what  we believe  were important overview papers
             or papers that would lead the  reader to  the most current, relevant
             literature or to  important ongoing studies.

             See also our response to comment 4.


4.  Comment  of J.H. Hughes, Commonwealth Edison,  Chicago, Illinois:

    We have  prepared a modified  Qualifying  Statement  which is attached for
    Panel consideration.  (Statement not attached - cf. written reply to
    this comment).

    Written  reply of T.A. Edsall, U.S.  Fish and Wildlife Service, Ann Arbor,
    Michigan:

    The Report now carries a Qualifying Statement that  was  approved by a majority
    of the Panel  on July 8, 1975.


5.  Comment  of J.H. Hughes, Commonwealth Edison,  Chicago, Illinois:

    Our last general consideration relates  to impingement and station entrainment
    of various fish life history stages.  A different committee addressed these
    considerations, and all reference in the Panel Report to fish impingement and
    entrainment should be deleted as referenced to the  Intake Committee  Report.
    We further note that neither consideration  was a  charge of the  Panel in  the
    November 9, 1972, U.S. EPA Statement which  established the Intake Committee
    and Panel.

    Written  reply of T.A. Edsall, U.S.  Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We believe that the Panel was charged by the Region  V Administrator to deal
    with the subject of cooling  water use,  which  includes consideration  of the
    entrapment/entrainment issue.

    As authors of the Fisheries  Section we  exercised  our prerogative  of  modifying
    the content of that section.  The opportunity to  comment on that  section in
    your letter of July 3, 1975, was afforded you.
                                  357

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6.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    We strongly recommend that this Panel meet all  of the original directives
    before assuming additional responsibilities.  For example, the charge to the
    Panel was "to review background information dealing with past, present and
    future studies relating to thermal discharges in Lake Michigan".  This has not
    been done, and in fact this charge should have been addressed before any
    recommendation related to additional studies was made.  The recommendation
    for additional studies was the last and not first charge of the Panel which
    is the logical order by which the charges should be addressed.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We believe the record shows that the Panel reviewed the ongoing research
    programs at the Cook, Zion and Point Beach plants.


7.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    The Fisheries Section consists entirely of additional studies without review of
    past, present and planned future studies to support their proposal or list
    of priorities.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We cannot comment on the companies "planned future studies" because we have
    not been privileged to see these plans (but see also our response to
    comment 6).


8.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    The Fisheries Section should also delete references to impingement since the
    previous report we reviewed did not discuss impingement.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor.
    Michigan:

    We have discussed impingement only to the extent we believed necessary to
    provide an adequate perspective for viewing discharge effects.


9.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

    We strongly disagree with the statement on page 245 which indicates that
    current information on rhe abundance and dynamics of fish stocks is inadequate
    to assess impingement losses as they relate to respective populations.  There
    is an abundance of literature or unpublished information related to stocking
    rates, commercial catch and standing crop of several species.  Losses at
    screens are currently being computed and these losses can easily be compared
    to these population statistics to determine if there is a concern.
                                  358

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     Written reply of T.A.  Edsall.  U.S.  Fish  and  Wildlife  Service.  Ann  Arbor,
     Michigan:

     We point out on page  293  of the  Report that  limited information  does  exist
     on the abundance and  dynamics  of the fish  populations of Lake  Michigan
     (and indeed reference  our unpublished report dealing  in  part with  alewife
     abundance in Lake Michigan).   However, we  believe, as stated in  the Report,
     that the available information is not yet  adequate to assess the significance
     of the impingement losses at Lake Michigan power plants, and (as also stated
     in the Report)  that the present  basis for  concern over the  adverse effects
     of existing power plants  on the  fishery  productivity  of  the lake is partly
     conjectural.

     We assume that if an  adequate  demonstration  of the significance  (or non-signif-
     icance) of these impingement losses  could  be made on  the basis of  the available
     data that such  a demonstration would probably have been  made.


10.   Comment of J.H. Hughes, Commonwealth Edison, Chicago. Illinois:

     On page 293, the authors  reference  a report  which contains  a standing crop
     estimate of alewives.  This is undoubtedly the species which constitutes most
     of the biomass  removed at traveling  screens.  Yet from reading page 245, one
     is led to believe there is no  information  available.

     Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife  Service,  Ann  Arbor,
     Michigan:

     We certainly did not  intend to imply that  no information is available and
     would be agreeable to  inserting  a parenthetical  statement on page  245
     directing the reader  to page 285 of  the  report.


11.   Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois;

     We have no additional  general  comments about the Fisheries  Section and would
     like now to specifically  address the before  and  after studies  described on
     pages 258-276.   The following  is basically a reiteration of our  comments in
     my January 16,  1975,  letter which the authors have not addressed.

     Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife  Service.  Ann  Arbor,
     Michigan:

     See our response to comment 1.


12.   Comment of J.H. Hughes, Commonwealth Edison. Chicago. Illinois:

     The tremendous  effort  which the  study plan recommends will  not meet the
     stated objectives of  determining size of fish stocks  at  the specific sites.
     The authors indicate mark and  recapture  methods  will  be  used in  making these
     estimates.  All models, using  such a technique,  assume no immigration or
     emigration in the area for which the population  estimate is to be  made.  The
     authors should  review  the assumptions in those references they used to support
     their techniques on page  265.
                                   359

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     Written reply of T.A. Edsall, U.S.  Fish and Wildlife Service,  Ann  Arbor.
     Michigan:

     We are aware of the assumptions inherent in the use of mark and  recapture
     data to estimate population size.   The Before and After Section  of the
     Report does not recommend that mark and recapture studies  be used  for this
     purpose (see page 273 of the Report), but rather that they be  used to
     provide an assessment of which populations or stocks are resident  or not
     resident in the site area.

13.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     There is more than adequate information to document that considerable movement
     takes place within a given study area and plume area.  The authors should
     review some of the work conducted by Spigarelli (1972) at  Point  Beach.

     Written reply of T.A. Edsall. U.S.  Fish and Wildlife Service,  Ann  Arbor,
     Michigan:

     We refer the reader in particular to the following papers  which  describe
     onshore-offshore movements of fishes and movements of fishes within and
     between effluent plumes in Lake Michigan:  Wells, L. 1968.  Seasonal depth
     distribution of fish in southeastern Lake Michigan.  U.S.  Fish and Wildlife
     Service, Fish. Bull. 67(1): 1-15,  and to papers by Spigarelli, Spigarelli
     et al., Romberg et al., and Thommes et al. that appear in  the  Argonne
     National Laboratory Annual Report for 1973 (full  citations of  these latter
     papers are giver, in the Fisheries  Section of the Report).

14.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     Results of studies by Cochran (1974) at Waukegan Station demonstrated that
     the plume does not interrupt seasonal onshore-offshore movements,  and in
     general, plume abundance is not much different than abundance  in reference
     areas.

     Written reply of T.A. Edsall, U.S.  Fish and Wildlife Service,  Ann  Arbor,
     Michigan:

     We suggest the reader study carefully Cochran (1974) and also  those papers
     cited in the response to comment 14.

15.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     Not only would the program not determine population size,  which  is the stated
     objective, but it could result in  a greater kill  of sport  salmonids than
     impingement.

     Written reply of T.A. Edsall, U.S.  Fish and Wildlife Service,  Ann  Arbor,
     Michigan:

     Given a 6-year Before and After sampling program (as outlined  in the Report),
     an annual bottom gill net catch of 686 salmonids (data for 1973-1974; Table 1
     of your letter), a four-fold increase in sampling effort (comment  19), and
     100% mortality of fish caught in these nets (comment 20),  we assume you
     would calculate a maximum kill in  bottom gill nets, of (6 x 686 x 4 =) 16,486
     salmonids at the sampling site; using the data from Table  1  for  the 6 months


                                     360

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     in 1974 we assume you  would  calculate  a maximum  kill of  (6  x  474  x  2 x 4 =)
     22,752 salmonids  as  a  result of  the  sampling  plan.  Using a three-fold
     increase in sampling effort  (comment 20) we assume you would  calculate a
     kill  of (6 x 686  x 3 =)  12,348 salmonids at the  sampling site on  the basis
     of your 1973-1974 data (your Table 1)  and  a kill  of (6 x 474  x  2  x  3 =)
     8,532 salmonids on the basis of  your 1974  data  (your Table  1).

     Given an impingement kill  of 145 salmonids per year (1973-1974  data from
     Table 1 of your letter)  for  the  estimated  40-year life of the Zion  Plant
     (316a demonstration  for  the  Zion Plant) we calculate a maximum kill of
     (145  x 40 =) 5,800 salmonids by  impingement;  using the 1974 data  we calculate
     an impingement kill  of (138  x 2  x 40 =) 11,040  salmonids due  to impingement.

     The validity of the  above  estimates  for the field sampling  program  must be
     viewed in respect to the responses we  made below to comments  19-25  and 28-29.
     Likewise the estimates of  the impingement  loss  cannot be verified by us with-
     out information on the seasonal  pattern of entrainment during one calendar
     year  of full plant operation.

     We agree that the loss of  salmonids  and other valuable fishes killed by
     impingement and by the field sampling  program is regrettable, but we cannot
     offer any alternative  to measuring the effects  of cooling water use that does
     not require the sampling of  stocks and the killing of fish.

     As stated in paragraph 3 of  page 256 and paragraph 2 of page  257  of the Report,
     we clearly recognize that  sampling plans and  levels of sampling effort other
     than  those proposed  in these guidelines may be  adequate for answering tEe
     questions posed in these guidelines.   A clear demonstration of  which of these
     questions can or  cannot  be answered  with existing data or with  data from ongoing
     studies would be  of  great  interest to  the  Panel  and to us.


16.   Comment of J.H. Hughes,  Commonwealth Edison,  Chicago, Illinois:

     This  is the only  effect  of power plant operation, outside of  speculations about
     chlorine, for this group which has been documented.

     Written reply of  T.A.  Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     We refer the reader  to pages 35-46 and 71-74  in  Edsall and  Yocum  (1972)
     and to the papers of the Argonne National  Laboratory cited  in response to
     comment 13.

     We believe that no adequate  studies  have been done at Great  Lakes  power plants
     of the effects of plant  shutdown during that  period of the  year when
     salmonids in the  plume would be  susceptible to cold shock kill, despite the
     fact  that shutdowns  occur  at this time of  the year and that salmonids are
     present in the plumes  at this time of  the year;  adequate data are also lacking
     for the effects of gas bubble disease  despite the fact that conditions exist
     in effluent plumes during  the colder portion  of  the year that could cause
     mortality (see Otto, 1973; full  citation is given in the Fisheries  Section of
     the Report.)
                                   361

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17.  Comment of J.H. Hughes. Commonwealth Edison,  Chicago.  Illinois:

     Most State Conservation Departments would probably be  reluctant  to  allow
     such a program.

     Written reply of T.A.  Edsall,  U.S.  Fish and Wildlife Service. Ann Arbor,
     Michigan:

     We believe that the State Conservation Departments will  make the appropriate
     decision in this regard.
18.   Comment of J.H. Hughes, Commonwealth Edison,  Chicago.  Illinois:

     We made a comparison of salmonid impingement  at  Zion with  numbers  collected
     in the monitoring program.   Our sampling effort  is  about 3-4  times less than
     that recommended in the Report, and the results  of  this comparison can be
     found in the following table:

                    Comparison of salmonids  collected at
     Study
   Interval
   July 1973
      to
   June 1974
     Total
   July 1974
      to
   Dec. 1974
     Total
travelling screens
lake monitoring by gi
Species
with numbers collected in
11 nets, trawls
Sampling
and seines
Method
Gill Net Trawl Seine
Lake Trout
Rainbow Trout
Brown Trout
Coho Salmon
Chinook Salmon

Lake Trout
Rainbow Trout
Brown Trout
Coho Salmon
Chinook Salmon

237
11
41
339
58
686
152
24
55
116
127
474
12 0
3 3
18 12
2 0
4 330
39 345
1 0
0 1
1 0
0 0
1 16
3 17
Impingement



      1

      5

      4

    133

      2

    145


     13

     60

     21

     44

      0

    138
                                 362

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     Written reply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann Arbor.
     Michigan:

     We cannot  respond to this  comment without  being  advised  of  the manner  in
     which this estimate was  obtained  (see  also our response  to  comment  24).

19.   Comment of J.H.  Hughes,  Commonwealth Edison,  Chicago,  Illinois:

     Assuming 100% kill  of only gill net collected fish, the  number of sal mom'ds
     killed in  Zion's present monitoring program was  four  times  higher than the
     number impinged  in  the first year of operation,  at what  admittedly  was
     reduced operating levels.

     Written reply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann Arbor,
     Michigan:

     We have no basis for not accepting  this  statement.

20.   Comment of J.H.  Hughes,  Commonwealth Edison,  Chicago,  Illinois:

     The monitoring program for the last six  months of 1974 killed  about 2  1/2
     times more salmonids than  were impinged.

     Written reply of T.A.  Edsall,  U.S.  Fish  and Wildlife  Service,  Ann Arbor,
     Michigan:

     We believe the correct value,  based on the data  in Table 1  and the
     assumption of 100%  mortality is 3.4 rather than  2.5.

21.   Comment of J.H.  Hughes,  Commonwealth Edison,  Chicago,  Illinois:

     Assuming a proportional  increase  in the  number of salmonids killed  in
     'onitoring if the proposed study  plan  were initiated,  approximately 1350
     salmonids  would  have been  lost or about  10 times the  number impinged.  This
     projection was based on  increasing  the number of bottom  gill nets from
     16/month in our  present  monitoring  program to 46/month in the  Panel  Report.

     Writter raply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann Arbor.
     Michigan:

     See response to  comment  16.

     We believe the stated  assumption  of 100% mortality of salmonids captured
     in gill nets (and the  apparent implied assumption of  zero mortality of fish
     collected  in trawls and  seines?)  is open to debate.   Mortality would depend
     on a number of factors including:   the manner in which the  nets and their
     catch were handled; the  season of the  year (water temperature  is important);
     the size of the  individual  captured relative  to  the size of the net mesh in
     which the  individual was captured;  the species captured  (large coho salmon
     die quickly in gill nets and chinook salmon less rapidly whereas lake  trout
     can survive gill  net capture and  release if proper precautions are  taken).

     Assuming a 100%  kill  of  the 474 salmonids  captured in  gill  nets (comment 20)
     and a three-fold increase  in sampling  effort  (comment  19) you  would expect
     a kill  of  1,422  fish;  likewise a  four-fold increase in sampling
                                    363

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     effort would result in a kill of 1,894 salmonids—more than a ten-fold
     increase.  However, we believe these estimates of kill are open to debate
     because the assumption of 100% mortality is not verified (see response to
     comment 20) and because it has not been shown that estimates of a three- to
     four-fold increase in sampling effort reflect sampling effort that would
     occur at times and places where salmonids would be present (see comment 22).


22.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     These estimates did not include any salmonids which would be killed by the
     oblique nets which would substantially increase the number killed.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     Generally oblique gill nets catch far fewer fish per linear foot of net
     than do bottom gill nets, unless fish are distributed throughout the water
     column or are much less abundant on the bottom than at higher levels in
     the water column.

     See also our response to comment 21.


23.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     It can also be expected that the number killed would increase for power
     plants located in states where extensive salmonid stocking programs are
     underway.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     We agree that larger numbers of salmonids probably would be captured and
     killed in areas of higher salmonid abundance.


24.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     We did not have time to stratify these projections by depth contour...

     Written reply of T.A. Edsall. U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan;

     This is essential if your statements regarding the magnitude of the loss
     of salmonids resulting from implementation of the sampling plan outlined
     in the Fisheries Section of the Report are to be accepted at face value.


25.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     ...but we did not use the general tactic employed by Mr. Edsall and
     Mr. Yocum in their review of power plant studies.  In this case we would
     have selected the single gill net with the highest number of salmonids  and
     multiplied by 552 or the total number of sets for each year.
                                 364

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     Written reply of T.A.  Edsall.  U.S.  Fish  and  Wildlife Service,  Ann  Arbor,
     Michigan:

     This comment appears  to be related  to a  review we prepared for the Panel
     of the PL  92-500, section 316a demonstration for the Zion Plant.   We
     believe it would not  be proper to deal with  it here but wish to point out
     that it suggests that the view expressed in  comment 6 is not entirely
     justified.


26.  Comment of J.H.  Hughes, Commonwealth Edison, Chicago, Illinois:

     The before and after  studies  are estimated to cost approximately $1 million
     dollars/year or $6 million dollars  for a new station with 3000-4000 cfs
     intake flow.

     Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife Service,  Ann  Arbor,
     Michigan:

     We cannot  respond to  this comment without access to the cost factors  on
     which the  estimate is based.


27.  Comment of J.H.  Hughes, Commonwealth Edison, Chicago, Illinois:

     In light of the above review,  the studies should be substantially  reduced.
     We recommend that sampling be  done  only  within the 10 meter depth  contour
     as recommended by Mr.  Patriarche.  In addition, sampling for quantitative
     purposes should also  be designed to evaluate primarily the dominant species
     as recommended by Dr.  Verdiun.
     (NOTE:  Six lines of  comment  have been deleted here and are presented
             below as comment 28.)
     An attempt to detect  these differences at each location over time  and between
     locations  within time in Figure VII-3 for most species would be ecologically
     irresponsible and should require an Environmental Impact Statement.

     Thus, we urge that for quantitative purposes only two locations,  one  reference
     and one experimental, be sampled with sufficient intensity to  detect  a 20%
     change. This experimental design would  permit an evaluation of preoperational-
     operational abundances as well as attraction - avoidance to the thermal  plume.
     Furthermore, the sampling effort should  be restricted only to  dominant species.
     These studies, including the  bottom trawls,  use relative abundance as an
     index to population change and do not estimate population size.

     Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife Service.  Ann  Arbor,
     Michigan:

     We believe that the Questions  to be Answered that are presented in the
     Fisheries  (and Entrapment/Entrainment) Section(s) of the Report require
     answers if the effects of cooling water  use  on the fish and the fisheries
     of Lake Michigan are  to be adequately assessed.  These Questions can  be
     answered with existing data if adequate  data exist, or with new data  yet
     to be collected.

     We enclose a copy of  our response to Dr. Ney's letter of July 1, 1975, which
     deals with the issues raised  in your comment above.  (Enclosure is not a
     part of this appendix.)


                                  365

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28.  Comment of J.H. Hughes, Commonwealth Edison, Chicago, Illinois:

     On page 257, the authors recommend a sampling effort which can detect a
     20% change in population size with a = 0.05.  This should only be done for
     major species at a few locations since the number of replicates  at each
     location would also have to be substantially increased above the two
     replicates the authors recommend if they wish to detect a 20% change.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     We believe Mr. Howe informed us that a 20% change in population  size with
     a = 0.05 could be obtained with the data currently being collected for
     your company which we believe involves duplicate (two replicates) sampling
     (Cochran 1974).


              **************************
 1.   Comment of J.J. Ney, Wisconsin Electric Power Company,  Milwaukee,  Wisconsin:

     It is unfortunately not possible to endorse this section or even  to  provide
     brief constructive comments which render it more scientifically acceptable.
     A number of fisheries biologists who have reviewed it have expressed strong
     reservations about both the feasibility of the proposed program and  its
     ability to answer relevant questions concerning cooling water effects.
     Alternative methodology has been suggested but largely  ignored.

     Written reply of T.A. Edsall, U.S.  Fish and Wildlife Service, Ann  Arbor,
     Michigan:

     Approximately 100 copies of the Lake Michigan Cooling Water Studies  Panel
     Report were distributed for comment and we have attempted to respond (as
     directed by the Panel on 10/1/74) verbally or in writing to each person
     who offered comments of substance on the fisheries section of the  Report
     and to make changes in the text of the Report that we believed would improve
     the usefulness of that section of the Report as a guideline for assessing
     the local and lakewide effects of cooling water use on the fish and the
     fisheries of Lake Michigan.

     Issues of substance in these written comments that did  not result  in modifi-
     cation of the text of the final  draft of the Report should be included in the
     Appendix of the Report.


 2.   Comment of J.J. Ney, Wisconsin Electric Power Company.  Milwaukee,  Wisconsin:

     The description of intake effects on Lake Michigan fishes (pp.  246-248 and
     p. 250) is completely out of place in this section.   The situation has been
     thoroughly discussed in the Lake Michigan Cooling Water Intake Structure
     Technical Committee Report (1973) and in Section VIII of this document.
     Inclusion of a separate interpretation of the problem here serves  only to
     further confuse the issue.
                                   366

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    Written reply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann  Arbor,
    Michigan:

    We believe that the charge to  the  LMCWSP by the Region  V Administrator
    included consideration of intake effects.   We  have  discussed  intake effects
    in Section VII of the  Report only  to the extent necessary to  provide an
    adequate perspective for viewing discharge  effects.


3.  Comment of J.J. Ney. Wisconsin Electric  Power  Company,  Milwaukee.  Wisconsin:

    The presentation of conjecture (e.g. "it is clear that  all  of the  fish large
    enough to  be impinged  on the travelling  screens of  existing power  plants  on
    Lake Michigan are killed"...p.  250)  as fact is especially deleterious to
    objective  analysis of  entrapment effects.

    Written reply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann  Arbor,
    Michigan:

    The reader is directed to paragraph  2 of page  250 of  the Report from which
    the above  quote was excerpted.  The  remainder  of the  quote is, "...when they
    are drawn  into these plants because  none of these plants are  now equipped
    with devices that would permit returning these entrapped or impinged fish
    to the lake alive." We believe this is  a true statement and  as such can  only
    aid in the objective analysis  of the effects of cooling water use.


4.  Comment of J.J. Ney, Wisconsin Electric  Power  Company,  Milwaukee,  Wisconsin:

    Most of the survival-threatening conditions noted on  pp. 251-254 have not
    been observed to occur as a result of Lake  Michigan cooling water  discharge.

    Written reply of T.A.  Edsall.  U.S.  Fish  and Wildlife  Service.  Ann  Arbor,
    Michigan:

    Various published studies (see pages 251-254 of the Report for references)
    suggest that high velocity jet-type  discharges may  cause damage to fish.
    Therefore, we believe  that this potential problem area  should be systematically
    investigated at Great  Lakes plants.

    We believe that the potentially adverse  effects of  chlorine in waste heat
    discharges have been adequately demonstrated (item  3  on page  251 of the Report).
    We also believe that predation on  fish fry  incapacitated by heat shock and
    mechanical damage has  been observed  in the  discharge  of the Nanticoke generating
    plant on Lake Erie (item 5 on  page 251 of the  Report).


5.  Comment of J.J. Ney, Wisconsin Electric  Power  Company,  Milwaukee,  Wisconsin:

    Laboratory experiments and studies of other ecosystems  serve  only  to define
    areas of potential  concern.

    Written reply of T.A.  Edsall,  U.S.  Fish  and Wildlife  Service,  Ann  Arbor,
    Michigan;

    We agree in part.  We  would add .that the behavioral responses  of unconfined
    fish at the cooling water use  site must  be  studied  to provide a completely


                                      367

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    satisfactory interpretation of laboratory or on-site bioassay studies.


6.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

    This report was designed as a guide for study design.  As with any guide,
    flexibility in implementation of procedures is a requisite.   While standardi-
    zation of methodology is a commendable goal, it should not be realized  at
    the expense of rational design.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We agree in principle (see pages 256 and 257 of the Report);  however, see  also
    our response to comment 18 as it relates to Lakewide Studies  and the attendant
    need for intersite standardization of sampling plans.


7.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

    Deviation from prescribed procedures (p. 257) do  not require "clear justifi-
    cation" (to whom?) since these procedures are often arbitrary in themselves
    (See comments 8, 9, 10, and 11)

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We had hoped that the Report would be viewed as an attempt to provide a
    comprehensive guide to aid in objectively determining the effects of cooling
    water use on the fish and fisheries of Lake Michigan.  We believe that  the
    accumulation of a scientifically acceptable body of fact regarding the  effects
    of this use of the waters of the lake is the best approach to resolving this
    issue objectively.  To this end we propose that the word "scientific" be
    inserted between the words "clear" and "justification."


8.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

    Encompassing and saturation of the plume area with sampling stations is
    exorbitantly expensive and unnecessary to determine cooling water effects.

    Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
    Michigan:

    We agree that the proposed sampling plan for Before and After studies will
    be expensive, but have no way of determining its cost relative to the cost
    of ongoing studies at Lake Michigan plants because information on the latter
    costs are generally unavailable to us.


9.  Comment of J.J. Ney, Wisconsin Electric Power Company. Milwaukee, Wisconsin:

    Stations should be limited to 6-foot-interval depth contours  within the
    plume area and at similar depths in a representative reference area.
                                    368

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     Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife  Service,  Ann Arbor,
     Michigan:

     We doubt that this  proposed  alternative  plan would  be an  adequate substitute
     for the plan offered in  the  Report.   (See  also  our  respone  to  comment  10).


10.  Comment of J.J.  Ney, Wisconsin Electric  Power  Company, Milwaukee,  Wisconsin:

     Adoption of the  pattern  in Figure VII-3  would impose  a degree  of rigidity
     on the study design which can't be  justified relative to  the variable
     configurations of plumes and lake morphometry for each unique  facility.

     Written reply of T.A.' Edsall.  U.S.  Fish  and  Wildlife  Service,  Ann Arbor,
     Michigan:

     The sampling grid (Figure VII-3) was  chosen  after examining a  large number
     of other study plans.  It incorporates what  we  believe are  the most desirable
     features of these other  study  plans as these features could be adapted to
     the situation on Lake Michigan (for example, see:  Carton,  R.R. and
     R.D. Hawkins. 1970.  Guidelines:  Biological surveys  at proposed heat
     discharge  sites. U.S. Environmental  Protection Agency.   Water Pollution
     Control Research Series. 16130—04/70.   99 pages).

     Two of the major considerations we  took  into account  in designing the  grid
     were lake  morphometry/bathymetry(one  determinant of the station locations
     are the depth contours)  and  the variable nature of  the effluent plumes (the
     grid was designed to cover that portion  of the  lake in which the waste heat
     from the plant could be  expected to be detectable,  plus a surrounding
     reference  or control area in which  no temperature elevation could be expected
     to occur).

     The area of highest station  density within the  grid reflects what we believe
     to be the  area in which  the  plume will be  most  frequently located.   Shoreline
     extensions of stations (up to  7.5 m in both  directions from the center line
     were included to take into account  the poorer mixing  conditions that occur
     when an offshore wind holds  the effluent against the  shoreline, thus creating
     a more elongate  plume.   The  lakeward  extension  of stations  (those along the
     center line on the  90-120 foot depth  contours)  was  included primarily  to
     permit documentation of  the  offshore-onshore distribution and  movements of
     fish in the site area, as these would affect seasonal  changes  in vulnerability
     of the various fish species  and their life stages to  the  effects of the plant.
     For example, if  it  could be  demonstrated that the offshore  waters of the lake
     (rather than only the waters of the littoral zone)  were an  important nursery
     area for most species of fish, our  concern over locating  plant intakes and
     discharges in the littoral zone would be greatly reduced.

     The "bilateral"  symmetry of  the grid  (stations  at depths  of 60 feet and
     shallower) was included  as a design feature  because it permits nested  analysis
     of the data.


11.  Comment of J.J.  Ney. Wisconsin Electric  Power Company. Milwaukee, Wisconsin:

     As a workable alternative, the following design should be considered:
                                    369

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               Sampling stations should be located at 6 foot-interval
               depth contours within the plume.  Owing to the variable
               configuration of plumes, potential sampling stations
               should be located on a grid, with actual stations dependent
               on the plume configuration on each sampling day.  One
               station should be located in the immediate proximity of
               the discharge.  Fixed stations should be located on the
               same depth contours in a representative, thermally-
               unaffected reference area.  To illustrate:  if the area!
               extent of a plume is limited to the 30 foot depth contour,
               stations would be located along the 6', 12', 18', 24',
               and 30' depth contours in the plume and in the reference
               area.  In this instance, a total of 10 stations would
               be sampled.

     Written reply of T.A. Edsall,. U.S. Fish and Wildlife Service. Ann Arbor.
     Michigan;

     Because the stations are fixed,they can provide the time-series data needed for
     a Before and After type analysis.  We believe that the alternate sampling plan
     outlined in the above comment would be more suitable for use in answering
     questions posed on pages 276-280 (Intensive Plume Studies) of the Report
     (see also our response to comment 10).

12.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

     The Materials and Methods described beginning page 260 are unnecessarily
     intensive to obtain answers to basic questions.  The costs (biological  and
     economic) of this type of sampling program cannot be justified, especially
     since direct evidence for significant adverse effects of thermal addition on
     Lake Michigan fishes is negligible.

     Written reply of T.A. Edsall. U.S. Fish and Wildlife Service. Ann Arbor.
     Michigan:

     To our knowledge it has not been adequately demonstrated that the effects of
     power plant discharges on the fishes of Lake Michigan are negligible.


13.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

     Comparison with the results of previous sampling indicate that the  gill net
     sampling program along would kill in excess of 20,000 salmonids/site/year.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     The validity of this statement cannot be determined by us because the  basis
     for the estimate is not given.


14.  Comment of J.J. Ney. Wisconsin Electric Power Company, Milwaukee. Wisconsin:

     This is clearly intolerable to the various management groups; no one wants to
     destroy the fishery in order to save it.
                                    370

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     Written  reply  of  T.A.  Edsall,  U.S.  Fish  and Wildlife  Service. Ann Arbor,
     Michigan:

     See our  response  to  comment  18.  Without answers  to the Questions posed on
     pages  293  and  294 of the  Report, we are  left with  little  on which to base
     our assessment of the  significance  of  the effect  of cooling water use.

     If use of  the  sampling plan  results in an intolerable kill of salmonids and
     other  desirable fish,  we  believe the management groups with proprietary
     interests  in the  fish  and fisheries of the lake would order a reduction in
     that kill.


15.   Comment  of J.J. Ney, Wisconsin Electric  Power  Company, Milwaukee, Wisconsin:

     The following  modifications  are suggested for  consideration in  development
     of a realistic sampling plan:

     Page 260 - la.  Trawling  should be  conducted on transects along contours,
     not at stations.

     Written  reply  of  T.A.  Edsall,  U.S.  Fish  and Wildlife  Service, Ann Arbor,
     Michigan:

     This is  covered in item c.2. on page 261 of the Report.


16.   Comment  of J.J. Ney, Wisconsin Electric  Power  Company, Milwaukee, Wisconsin:

     Page 260 - lb(l). Use of the  16 ft. bottom trawl  results in redundant sampling
     in the 0-10 ft. zone.   b(l)  can be  deleted in  favor of using the 39 ft. trawl
     at depths  greater than 6  feet  and the  seine from  0-6  feet.

     Written  reply  of  T.A.  Edsall.  U.S.  Fish  and Wildlife  Service. Ann Arbor.
     Michigan:

     The vessel  required  to tow a 39-foot trawl effectively would probably not
     be able  to operate safely in less than 10-12 feet of  water; the 16-foot trawl
     could  be towed effectively and safely  with smaller, shallow draft vessels at
     water  depths of less than 10 feet.


17.   Comment  of J.J. Ney, Wisconsin Electric  Power  Company, Milwaukee, Wisconsin:

     Page 260.   Bottom trawling is  often not  possible  due  to obstacles (rocks, trees,
     etc.).  Provision should  be  made for substitution  of  midwater trawl, so that
     sampling will  cover  those depths contacted by  the  plume on the  sampling day.

     Written  reply  of  T.A.  Edsall.  U.S.  Fish  and Wildlife  Service. Ann Arbor.
     Michigan;

     If bottom  trawling in  shallow  water is not possible,  we would recommend the
     use of a seine or trapnet.   We believe midwater trawling  technology has not
     been developed to the  point  that we would recommend that  it be  used routinely
     as a substitute for  bottom trawling in shallow water.
                                     371

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18.  Comment of J.J. Ney, Wisconsin Electric Power Company.  Milwaukee,  Wisconsin;

     Page 262- 1.3d.  Age determination, if it is to characterize populations,
     is an involved, laborious process which must be performed for each species.
     Length-frequency analyses and condition factor determinations will  provide
     sufficient information concerning population structure  and well-being  to
     reveal  harmful effects.  Aging, if conducted at all,  should be confined to
     species known to be resident.  Applying this effort to  transients  in a
     localized study is fruitless.

     Written reply of T.A. Edsall. U.S. Fish and Wildlife  Service. Ann  Arbor.
     Michigan:

     Section VII of the Report deals with the assessment of  both local  and  lake-
     wide effects.  The objectives of the lakewide studies are stated on page 292
     of the Report and include a description of the age structure of the fish
     populations of importance.  The (local) studies we have outlined for
     implementation at cooling water use sites are designed  to provide  data that
     will contribute to the success of the lakewide study  effort.

     We would be agreeable to insertion of the following paragraph in the text
     of the Report on page 262 between paragraph 2 and 3 of  section 3d:

     Scale samples should be taken monthly from at least 300 fish (age  group I
     and older) of each of the following species:  smelt,  alewife, yellow perch,
     and each species of coregonine captured.  If subsequent analyses of the age
     composition o^ the annual catch shows agreement with  estimates obtained by
     resource agencies conducting similar research on the  fish stocks of the
     lake, this sampling effort can be reduced so that scales are collected
     annually only during one of the fall sampling series.


19.  Comment of J.J. Ney, Wisconsin Electric Power Company.  Milwaukee,  Wisconsin:

     Page 264-265-(5)(a) through (5)(c) - Feeding habits, contamination,  and
     fecundity analyses should be limited to only those species known or suspected
     of prolonged plume residence.  Killing deepwater ciscoes, for example, to
     perform these analyses is both superfluous and deleterious.   (5) should
     include a provision limiting sample preservation to those species  suspected
    . of plume residence.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife  Service. Ann  Arbor,
     Michigan:

     We agree that items 5a-c should be performed on fish  known or suspected
     of prolonged plume residence.  However, we do not wish  to exclude  the
     possible need to study plume effects on those other fish species which may
     avoid the plume or reside in the plume briefly.  For  example:  if  the
     periodic presence of the plume in a given area alters the benthos  community
     in that area, the feeding opportunity of fish (that avoid the plume but
     move into that area after the plume has departed) may be altered;  also
     the successful incubation of fish eggs spawned in a given area when the
     plume is not impacting that area, may be reduced when the plume returns.
                                  372

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20.   Comment of J.J.  Ney, Wisconsin  Electric  Power  Company, Milwaukee, Wisconsin:

     Page 265 e(l).   Population estimates  should  only  be made  for  resident
     populations.  As with  aging,  population  estimation is a laborious and  some-
     what sophisticated  process and  should not  be performed on transient  species,
     estimates for which would be  useless.

     Written reply of T.A.  Edsall. U.S.  Fish  and  Wildlife Service,  Ann Arbor,
     Michigan:

     See paragraph 1  of  the response to  Comment 18.


21.   Comment of J.J.  Ney, Wisconsin  Electric  Power Company, Milwaukee, Wisconsin:

     Page 266 2(a).   Gill net sets should  be  located as follows:   one oblique and
     one bottom net at near field  and at far  field  stations in the  plume  and at
     comparable depths in the reference  area.   Sampling frequency  should  be
     limited to four  successive 12-hour  sets.

     Written reply of T.A.  Edsall, U.S.  Fish  and  Wildlife Service,  Ann Arbor,
     Michigan:

     Reduction in  the sampling effort below levels  specified on pages 266 and
     269 of the Report is desirable  (see paragraph  2 on page 257 of the Report),
     if it can be  demonstrated (for  the  entire  area impacted by the plume during
     all seasons of the  year) that the "Questions to be Answered"  on page 258 of
     the Report can be adequately  answered with a reduced sampling  effort.

     We do not believe the  alternate sampling program  proposed in  the above comment
     would be an adequate substitute for the  sampling  plan presented for  use in
     the Before and After Section  of the Report;  we believe the alternate sampling
     plan presented in the  comment above may  be better suited  for  studies of the
     type outlined in the Intensive  Plume  Studies portion of the Report (pages 276-
     287).


22.   Comment of J.J.  Ney, Wisconsin  Electric  Power  Company, Milwaukee, Wisconsin:

     Page 271  4a.  Fry sampling should be  conducted on transects along contours
     from 6' to edge  of  plume and  over same depths  in  reference area.  Sample at
     surface, middle  depth  and, where possible, bottom.  4c (2) should advise
     night sampling to reduce larval  avoidance.

     Written reply of T.A.  Edsall, U.S.  Fish  and  Wildlife Service,  Ann Arbor.
     Michigan:

     See response  to  comment 21.


23.   Comment of J.J.  Ney, Wisconsin  Electric  Power  Company, Milwaukee, Wisconsin:

     Page 272 5a.  Pump  sampling  stations  should  be confined to 6'  interval
     depth contours in plume and  reference area.  5b -  Water should  be passed
     through 351 micron  mesh to be compatible with  entrainment sampling.
     5c(2) Sampling should  commence  April  15, unless smelt are not  considered.
                                  373

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     Written reply of T.A. Edsall. U.S. Fish and Wildlife Service. Ann Arbor.
     Michigan:

     See response to comment 21.

     A number 30 mesh screen would retain the smallest fish egg that would be
     encountered in Lake Michigan, therefore, there is no need to use a 351
     micron mesh for pump sampling for fish eggs.

     We agree that pump sampling should begin early enough in the spring to
     assess deposition of eggs by smelt.


24.  Comment of J.J. Ney, Wisconsin Electric Power Company. Milwaukee, Wisconsin:

     Page 275 6(b) (2).  Tagging should be performed coincidental to other
     sampling, with viable fish tagged and returned.  The separate effort outlined
     here is unnecessary unless viable fish are not captured by trawl, seine and
     gill net.  Tagging should also be confined to these species suspected of
     plume residence e.g., if brown trout members are seasonally higher in the
     plume than in the reference area, tagging studies should be performed to
     determine potential interference of the plume with migratory behavior.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service. Ann Arbor,
     Michigan:

     We agree that "coincidental tagging" may provide enough fish to meet Before
     and After study needs; but see also pages 276-287 of the Report.


25.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

     Intensive Plume Studies (page 276) and Laboratory Studies (page 289) afford
     the best means of defining real  problems of fish relative to cooling water
     discharge.  In the logical sequence of investigation, the seasonal plume
     residence patterns of the various species should first be determined.  Results
     of thermal laboratory bioassay and behavioral studies can then be applied to
     focus concern on those species for which adverse effects can be anticipated.
     The field sampling program should then be refined to determine the magnitude
     of such effects.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     In general we agree that the most obvious direct effects of cooling water
     discharges on Lake Michigan fish will be most easily defined by means of
     Intensive Plume Studies and Laboratory Studies.  We are in general agreement
     with the rest of the comment.


26.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee. Wisconsin:

     The results of both Intensive Plume and Laboratory Studies should have
     general application and need not be replicated at each site.
                                   374

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     Written reply of T.A.  Edsall.  U.S.  Fish and Wildlife  Service. Ann Arbor.
     Michigan:

     We believe that some of  the  studies conducted at  each cooling water  use
     site may not have to be  repeated  at other sites.


27,,   Comment of J.J.  Ney, Wisconsin Electric Power Company,  Milwaukee, Wisconsin:

     Intensive Plume Study  No.  4  (p. 286)  is only relevant if  ATs experienced  in
     plume shifts or upwelling  have a  potential for  deleterious  effects.  This
     information has been,  or can be,  obtained in bioassay.  The same holds for
     chlorination.   This study  guide should note that  efforts  should be confined
     to those species which show  adverse effects at  the AT or  chlorination levels
     observed at the site.

     Written reply of T.A.  Edsall.  U.S.  Fish and Wildlife  Service. Ann Arbor,
     Michigan:

     We agree that information  from the  literature,  or from the  results of on-site
     bioassay studies or studies  conducted in the laboratory,  together with infor-
     mation on plant operating  characteristics and local limnological conditions
     can be used to provide a demonstration of the likelihood  of damage to fish as
     a result of the discharge  of waste  heat and toxic chemicals at a given site;
     therefore, we also agree that  these "non-field" studies can serve adequately
   .  as the basis for excluding species  of fish from study of  specific effects at
     particular cooling water use sites.


28.   Comment of J.J.  Ney, Wisconsin Electric Power Company,  Milwaukee, Wisconsin:

     There is little evidence that  water quality in  Lake Michigan varies  so widely
     as to necessitate site-specific chlorine toxicity tests (p. 287).  Section III
     of this report, while  describing  chemical parameters  makes  no mention (other
     than influence of adjacent tributary  streams) of  intra-lake water quality
     differences.  Information  obtained  using water  within the range of normal
     Lake Michigan chemical composition  should be of general application.

     Written reply of T.A.  Edsall.  U.S.  Fish and Wildlife  Service. Ann Arbor.
     Michigan:

     We have seen no evidence to  indicate  that water quality in  Lake Michigan  at
     the various cooling water  use  sites is so uniform as  to preclude the need
     for onsite or site-specific  chlorine  toxicity tests.   Furthermore the design
     and operating characteristics  of  plants on Lake Michigan  vary widely and  these
     may be important in determining the probability of damage to fish occurring
     as the result of chlorination.


29.   Comment of J.J.  Ney, Wisconsin Electric Power Company,  Milwaukee, Wisconsin:

     (Pages 287-289).  Although on-site  bioassays can  be of value in determining
     actual effects of chlorination, cold  shock etc. as they occur in the field,
     it should be recognized  that in-situ  bioassays  which  require caging  of fisK
     apply artificial stress  which  can have an additive effect.  Results  of such
     studies must be considered relative to their limitations.  If the natural
                                  375

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     environment cannot be successfully simulated, on-site bioassays and
     behavioral experiments may be worthless.  Cage studies can be used to verify
     results of laboratory experiments - an iterative procedure.  However, results
     at odds with lab findings are of value in inverse proportion to the artifi-
     ciality of the situation.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor.
     Michigan:

     We realize the laboratory studies and on-site bioassays cannot be expected
     to reproduce exactly the field conditions that result from cooling water use
     at a particular site.  We recognize that the behavioral responses of unconfined
     fish at a cooling water use site must also be studied to provide a completely
     satisfactory interpretation of non-field studies and therefore of the effects
     of cooling water use.

     The procedures that we recommend on pages 288 and 289 of the Report represent
     the best methodological approaches available at the time we drafted our contri-
     bution to the Report.  As better methods become available they should be used.


30.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee. Wisconsin:

     Materials and Methods 1, 3, and 5 (pp. 288-289) are completely artificial
     situations and results can have, at best, limited relevance.  They should
     be discounted.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     We disagree (see responses to comments 27 and 29).


31.  Comment of J.J. Ney, Wisconsin Electric Power Company, Milwaukee, Wisconsin:

     In addition, all cage studies must include control  groups and both groups
     should be tested for sub-lethal physiological stress.  It should also be noted
     that results of all of these experiments have general application.

     Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
     Michigan:

     We agree that the use of control or reference groups is essential and that
     measures of both acute and sub-acute effects may be necessary and that some of
     the results of these studies may have application at more than one cooling
     water use site.


                     Comments related to Section VIII
              Measurement of the Effects of Cooling Water Use

                   on Entrapped and Entrained Organisms
                                   376

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Comment of R.S.  Benda, Aquinas  College,  Grand  Rapids,  Michigan:

Pump Location -  Pumps should be located  behind the  traveling  screens  if at
all possible to  avoid the problem of pumping adult  fish  in  the collecting
nets.  We have experienced several  pump cloggings when  numerous adult  fish
inhabit the intake bays.
        reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife  Service,  Ann Arbor,
Michigan:

I agree completely.


Comment of R.S. Benda, Aquinas College,  Grand Rapids, Michigan:

Planktonic eggs - It has been  impossible to  establish numbers  of planktonic
eggs being entrained due to the problem  referred to in Pump  Location (above)  and
compounded by the occurrence of ripe  females in  the intake that  expel   their
eggs during the stress of impingement.   These eggs  would be  sampled on either
side of the screens  thus possibly resulting  in a significant error in  estimates
of planktonic eggs.

Written reply of T.A.  Edsall,  U.S.  Fish  and  Wildlife  Service,  Ann Arbor,
Michigan:

I believe that the freshwater  drum (Aplodinotus  grunniens) is  the only fish
species in the Great Lakes that has a truly  planktonic egg.

The problem of distinguishing  between eggs entrained  from the  lake and those
expelled by entrained fish may be a difficult one,  however,  sampling simultane-
ously at the intake  crib and in the traveling screen  well  should provide  a  basis
for determining the  relative importance  of the two  sources.


Comment of R.S. Benda, Aquinas College,  Grand Rapids, Michigan:

Net Mesh Size - The  recommended 351 micron size  is  not a normal  stock  size  at
Wildco, thus necessitating a special  size.   Why  is  351 micron  mesh so  critical.
Why not their 363 micron size?  Its been our experience that the small 333
micron size we are using collects so  much zooplankton and suspended material
that samples take much longer  to pick at times.   We are alsp using 571 micron
mesh at the Monroe Plant, due  to the  heavy organic  load, and still collect  eggs
and all developmental  stages of fish.

Written reply of T.A.  Edsall ,  U.S.  Fish  and  Wildlife  Service,  Ann Arbor,
Michigan:

Our experience has show us that 351-micron mesh  is  about the largest mesh size
that will capture the smallest fish eggs and larvae found in the Great Lakes.
We have conducted no mesh selectivity studies using 363-micron mesh but suspect  '
that it would result in a slightly lowered catch of the earliest life  stages
of some Great Lakes  species.  There can  also be  little doubt that 571-micron
mesh would permit the loss of  a considerably higher percentage of the  earliest
life stages of several species of Great  Lakes fish  than would  either 351- or
363-micron mesh.                                          '
                                 377

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Comment of R.S. Benda, Aquinas College, Grand Rapids, Michigan:

Pump Type - What type of pump can be used to insure an adequate sample size and
still not cause damage and mortality to the larval fish?  This should be
included in this report, and also inclusion of the basic plan for the Great
Lakes Fishery Laboratory's  automated pump system, if that is the recommended
type.

Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor.
Michigan:

The Report suggests (pages 333-334) that "damage and mortality" assessment be
made with samples collected in plankton nets suspended in the cooling system
flow rather than with the samples obtained by pumping.


Comment of R.S. Benda, Aquinas College, Grand Rapids, Michigan:

Pump Numbers - What procedure should be utilized to establish exact pump
locations when the plant has more than one unit?  This should be in this
section, especially when investigators are asked to "document horizontal and
vertical stratification" in the intake and now I assume in the discharge.

Written reply of T.A. Edsall, U.S. Fish and Wildlife Service, Ann Arbor,
Michigan:

I can only suggest that the investigator take the empirical  approach in
answering this question.  If the investigation cannot demonstrate that he has
satisfied the assumptions implicit in sampling, then his results surely will
be open to debate.


Comment of R.S. Benda, Aquinas College, Grand Rapids, Michigan:

Determination of Live and Dead Larva.  Has any work been done on survival
rates of larval fish pumped and collected in nets and the effect on them?
How long can a larval fish survive retention in a net, a matter of minutes or
several hours.  This will directly affect frequency of sample removal  and
determination of mortality.

Written reply of T.A. Edsall. U.S. Fish and Wildlife Service. Ann Arbor,
Michigan:

I agree that information of this kind is needed to adequately evaluate the
effects of entrainment in some situations.


Comment of R.S. Benda, Aquinas College, Grand Rapids, Michigan:

I agree this is probably one of the most important parts of the overall
evaluation of the impact.of once-through cooling, but it seems that aspects
are going to be difficult if not impossible to determine (i.e. page 330,
number 9).  Thank you for allowing me to comment on the section.   I'm sure
its been a difficult task to accomplish.
                                 378

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Written reply of T.A.  Edsall.  U.S.  Fish  and  Wildlife  Service.  Ann  Arbor.
Michigan:

I agree that it may be difficult to answer question 9 on  page  330, but  if the
answer to question 3 on page  329 is "yes", then  it becomes  necessary to
address question 9 if means other than closed cycle cooling are sought  to
reduce entrainment damage.


Comment of J.R. Gammon, De  Pauw University,  Greencastle,  Indiana:

I have expressed the view previously concerning  the entrainment section of the
Report, but let me briefly  reiterate my  views.   I  believe that the research
program outlined in this section is a very complete and ambitious  one.  I
would very much like to see it implemented at one  or  more (up  to four strategi-
cally located) stations to  test its capability and search out  its  difficulties.
However, I feel that such a program at each  and  every power station would not
be reasonable in terms of use  of time, effort, and money.

A written reply to this comment was not  received.


Comment of J.J. Ney, Wisconsin Electric  Power Company, Milwaukee,  Wisconsin:

Page 329, Number 3.  The phrase "when added  to the other  losses resulting from
cooling water use" should be  deleted.  Evaluation  of  cooling water intake
structure impact should be  made separately (per  Public Law 92-500, Section 316 (b))
from other cooling water use  effects.  Remedial  (best available) technology for
cooling water intakes to alleviate entrainment/entrapment impact can be applied
without substantial modifications to other facets  of  power plant operation.
Since evaluation of the impact and the application of potential corrective
measures for cooling water  intakes are not dependent  on other  aspects of  cooling
water use, the issue is self-contained.   If  cooling water use  effects are
considered in toto, it will be extremely difficult to determine appropriate
corrective action.  If the  present wording is retained, it could be construed
that Questions 4 - 9 on pp. 329-330 should be addressed in situations where
entrainment/entrapment is negligible, but other  cooling water  use  effects on
fish populations are significant.  In this instance,  considerable  effort  and
expense would be directed toward answering irrelevant questions.

Written reply of T.A.  Edsall.  U.S. Fish  and  Wildlife  Service.  Ann  Arbor.
Michigan:

I have asked to have the words, "...in itself, or...", inserted immediately
ahead of the phrase you suggest be deleted.  I believe that this addition  will
help convey to the reader the  idea that evaluation of the significance  of the
effects of entrainment on "non-screenable" fish, fish larvae,  and  eggs  should
first be made independently of the other possible  adverse plant impacts on
these classes of organisms.  However, it should  also  be apparent to the reader
that the incremental loss of  fish, fish  larvae,  and eggs  cannot be judged
insignificant until it is added to the incremental losses caused by all of the
other aspects of plant operation and until this  "total" loss is evaluated in
respect to its impact on the  local and lakewide  fish  population for the (one)
plant operating alone and for the plant operating  in  concert with  other similar
plants on the same water body.
                                379

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 Comment of J.J.  Ney,  Wisconsin  Electric  Power  Company, Milwaukee, Wisconsin:

 Page  333,. Sampling Frequency and  Duration.   Sampling  should be performed
 continuously every fourth  day of  plant operation April 15  - October 31, during
 one year.   Sampling in additional years  should be  contingent on the results
 of the  first year's study  and may not be required.  The Lake Michigan Cooling
 Water Intake Technical Committee's  Report on the Best Available Technology
 (1973)  recommends  one day  per week  sampling  as a minimum.  The several regulatory
 agencies which are currently administering Lake Michigan entrainment survey
 programs have suggested sampling  of approximately this frequency.

 Written reply of T.A. Edsall. U.S.  Fish  and  Wildlife  Service, Ann Arbor,
 Michigan:

 I have  seen no data which  shows that "...sampling  every fourth day..." (etc.)
 would be adequate  to  describe the kinds  and  numbers of fish eggs and larvae
 (ichthyoplankton)  that are entrained (continuously),  and until such data
 demonstrating the  adequacy of that  sampling  frequency are  made available for
 public  review, I believe it is  appropriate for me  to  support the sampling
 program outlined in the Report.


 Comment of J.J.  Ney,-Wisconsin  Electric  Power  Company, Milwaukee, Wisconsin:

 Sample  Processing  (p. 333) and  Sampling  Process (p. 335) should be identical;
 instructions need  not be repeated.

 Written reply of T.A. Edsall, U.S.  Fish  and  Wildlife  Service, Ann Arbor,
 Michigan:

 I disagree.   The Sampling  Process outlined on  page 335 is  for studies
 designed to permit assessment of  in-plant mortality of non-screenable fish,
 fish  eggs  and larvae  and requires examination  of the  samples at the time they
 are collected.   The Sampling Process outlined  on page 333  is intended only to
 determine  the kinds and numbers of  non-screenable  fish, fish eggs, and larvae
 that  pass  through  the plant;  this can be done  from preserved samples as indicated
 on page 333.
                            General  Comments

                       related to Report Number 1


Comment of F.R. Boucher. Wisconsin Electric Power Company. Milwaukee.  Wisconsin:

I have reviewed and diseased with my staff the Lake Michigan Cooling  Water
Studies Panel (LMCWSP) Report recently entitled "A Statement of Concerns  and
Suggested Ecological Research" and offer the following general  comments as  a
member,;of the LMCWSP.

     1)  While the document may well represent a "best efforts" attempt
         by a panel of diverse technical background and interest, the  report
         unfortunately retains much of the inconsistency of approach,  format
         and possible purpose which plagued its earlier drafts.  Most  sections
         are reasonably well-organized, defining pertinent questions concerning


                                    380

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         cooling water effects  and proposing logical  measures  to  provide answers.
         This is especially true of the  Macrozoobenthos  Section.   Other sections,
         notably those dealing  with Primary Producer  and Consumer Communities
         and with Fisheries, appear significantly less rationally developed and
         may negatively affect  the utility of the entire report.   In  these
         sections, study measures of immense magnitude are  described,  often with
         no clear explanation of why they might be either necessary or even
         capable of providing useful  answers relative to cooling  water effects.
         Little or no concern is given to the feasibility of their implementation.
         It is obvious that the clarity  and logic of  these  sections must be
         markedly improved if our report is to reflect the  quality and intention
         of the Panel and be the meaningful  document  which  we  all  intend it to be.

     2)  As I understand the motion adopted by the Panel  at our October 1,  1974,
         meeting, comments on the program were to be  solicited for incorporation
         into the October 29th  draft of  the Report.   Comments  not incorporated
         were to be rebutted by the section authors.  It is apparent  that comments
         on several sections were neither incorporated nor  rebutted.   For example,
         Dr. J.J. Ney and other fisheries biologists  have charged (ref.  J.  Ney
         letter to T. Edsall» December 26, 1974)  that the Fishery sampling  program
         would bill an intolerable (to management groups) number  of sport fish.
         This allegation, if true, could jeopardize acceptance of the  entire
         report; yet no response to it has been made. To satisfy the  explicit
         intention of the Panel expressed by its  action  of  October 1st,  the Report
         cannot be finalized until the solicited  comments are  considered in this
         manner.

     3)  As you yourself have noted in your June  6th  memorandum,  sections of
         the Report reflect the view of  a particular  author.   The Report clearly
         is not a product of the Panel on the whole.  It was for  this  very  reason
         that comments of other acknowledged experts  were requested so that a more
         balanced overview might be presented.  It is fundamental  to  the production
         of the Report as an objective and useful  document  that expert commentary
         not be ignored and that the procedure adopted by the  Panel be followed
         prior to its completion, printing and distribution.

Written reply of E.F. Stoermer, University of Michigan,  Ann Arbor,
Michigan:

Studies of the type outlined under the section on Primary Producer and Consumer
Communities are routinely accomplished by any number  of  scientific institutions.
I see no reason why the feasibility or implementation of such  a project should
present "immense" problems to any qualified investigator.

Reply of K.E. Bremer, U.S. Environmental Protection Agency, Chicago,  Illinois:

A reply to comment 2 is furnished on page 356, reply  to  comment number 2.


Comment of J.Z. Reynolds, Consumers Power Company, Jackson, Michigan:

This is in response to your request for  consideration and comment on  the final
draft of the Lake Michigan Cooling Water Studies  Panel Report  Number  1.   Inasmuch
as I have commented in detail on previous draft sections of the report,  I will
limit my remarks here to general observations of how  I feel about the  final
version of the report.
                                    381

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The improvements that have been made from earlier drafts are largely editorial
and do not reflect much responsiveness of a technical or objective nature to
the comments received.  The various sections remain largely the product of the
invividual authors, and are not a concensus of the Panel or those who commented.
The Microbiology and Fisheries Sections suffer most in this respect, since they
received the most critical comment but, lacking a formalized review procedure,
this must be the case to some degree for all sections.  Therefore, the Qualifying
Statement should more clearly emphasize that the different sections represent
the personal views of the authors and various references to "Panel" views scattered
throughout the report are generally those of the section authors.

The final title for the report adequately characterizes the content, but much of
the "suggested ecological research" has not been justified in terms of scientific
validity or cost effectiveness.  Suggested data collection activities are not
related to study objectives or the Panel's role of determining what is ecologically
significant or important.  Further, while the priorities for research in each
category reflect some ordering of concerns, there has been no attempt to relate
the priorities of one category to the relative needs in another.  This is a severe
limitation on the usefulness of the report.

I regret that I am not being very constructive in my comments, as you requested,
but I feel compelled to note also that the findings related to the charge to the
Panel, of reviewing and assessing the adequacy of studies relating to thermal
discharges, are not reflected in the report.  In many cases the Panel, in reviewing
specific study plans, determined them to be adequate, but comparison with the
"suggested ecological research" would indicate they are totally inadequate.  Such
contradictions without explanation, in my opinion, severely threaten the credibility
of the Panel as a technical advisory group.

A written reply to this comment was not received.
                                  382

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                                  TECHNICAL REPORT DATA
                           (Please read Instructions on the reverse before completing)
1. REPORT NO.
 EPA-905/3-75-001
                                                          3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
 A Statement of Concerns and Suggested  Ecological
 Research:  Report Number 1 of the  Lake Michigan
 Cooling Water Studies Panel
                                   5. REPORT DATE
                                    November, 1975
                                   6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
 Lake Michigan Cooling Water Studies  Panel
 C.D. Meyers and K.E. Bremer, editors
                                                          8. PERFORMING ORGANIZATION REPORT NO.
                                    Report Number  1
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Lake Michigan Cooling Water Studies  Panel
 U.S. Environmental Protection Agency
 230 South Dearborn Street
 Chicago, Illinois 60604
                                                          1O. PROGRAM ELEMENT NO.
                                   11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
 U.S.  Environmental Protection Agency
 Surveillance and Analysis Division, Region V
 230 South Dearborn Street
 Chicago, Illinois 60604
                                                          13. TYPE OF REPORT AND PERIOD COVERED
                                   14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
      This report presents a statement of concerns and suggested  research  by the
 Lake Michigan Cooling Water Studies  Panel.   The intent of the statement is to assist
 the development of investigations  of the effects of cooling water  use on  Lake Michi-
 gan.
      The introductory considerations of Lake Michigan are presented  in the first
 section.  The second section presents recommendations toward objective quantification
 of the effects of cooling water  use  through proper statistical planning,  study design,
 and data collection.  The remaining  seven sections relate information the authors
 consider basic to an understanding of the effects of cooling use on  physical and
 chemical aspects, primary producer and consumer communities, macrozoobenthos, fishery,
 entrapped and entrained organisms, and radioecology of Lake Michigan.
      All sections of the report  attempt to produce improvement in  research design and
 a trend toward standardization of  results.   In addition, questions are posed and
 ranked resulting in numerical priorities with the intent to guide  research in those
 areas of knowledge which are barriers to an adequate understanding of the effects of
 cooling water use.
17.
                               KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
                      b.lDENTIFIERS/OPEN ENDED TERMS  C.  COS AT I Field/Group
 Cooling Water
 Aquatic Biology
 Biostatistics
 Entrainment
 Benthos
 Plankton
 Fisheries
Hydrology
Water Chemistry
Limnology
Ecology
Lake Michigan
Thermal Effects
Radioecology
 6 F
13 B
18. DISTRIBUTION STATEMENT
 Limited number of copies  from  U.S.  EPA,
 Chicago.  At cost of publication  from NTIS,
 5285 Port Royal Rd., Springfield.Va.  22161.
                                             19. SECURITY CLASS (ThisReport)
                                                                        21. NO. OF PAGES
                      20. SECURITY CLASS {Thispage}
                                                22. PRICE
EPA Form 2220-1 (9-73)

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