Chesapeake Executive Council
                    903R88113
             Stock Assessment
                      Plan
        Chesapeake
                   Bay
             Program
        Agreement Commitment Report
TD

225

.C54

S861

copy 2
                     July 1988

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  Stock  Assessment  Plan
An Agreement Commitment Report from
    the Chesapeake Executive Council
                    U.S. Environmental Protection Agenqf
                    Region 111 Information Resourca
                    Center (3PM52)
                    841 Chestnut Street
                    Philadelphia, PA  19107
             Annapolis, Maryland

                July 1988

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                            ADOPTION STATEMENT
      We, the undersigned, adopt the Chesapeake Bay Stock Assessment Plan, as developed by
the Chesapeake Bay Stock Assessment Committee, in fulfillment of Living Resources Commit-
ment Number 2 of the 1987 Chesapeake Bay Agreement:

      "...by July, 1988, to develop, adopt and begin to implement a Bay-wide plan
      for the assessment of commercially, recreationally and selected ecologically
      valuable species."

      The Plan proposes improved means of assessing stocks of finfish and shellfish in the
Chesapeake Bay.   It identifies outstanding data needs for stock assessment models for Bay
fisheries. Recommendations include improved ways to collect catch, effort, and biological data
from commercial and recreational landings, in addition to long- term surveys for estimating relative
abundance of important species in all regions of  the Bay  and its tributaries.  There are
recommendations  in the  Plan for studies of early life stages designed to examine natural and
human-caused sources of mortality and to investigate biological effects of pollution, habitat loss,
and disease.

      The data collected in the recommended trawl and seine surveys will be used by the stock
assessment groups to develop short-term management related information and by monitoring
groups to track long-term trends. These stock assessments will be used in the development of
fisheries management plans due for thirteen species between July 1989 and 1992.

      We agree to support the Plan's recommendations for new efforts to collect basic, short- and
long-term data, consistent Bay-wide, that are essential for stock assessment and monitoring. We
recognize the need to commit financial and human resources to the task of developing and
implementing the recommendations of the plan. Finally, we direct the Chesapeake Bay Stock
Assessment Committee to prepare annual reports detailing the progress made in implementing the
Plan's recommendations.
For the Commonwealth of Virginia

For the State of Maryland

For the Commonwealth of Pennsylvania

For the United States of America

For the District of Columbia

For the Chesapeake Bay Commission

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                         FOREWORD
We,  the  undersigned,  adopt  the  Chesapeake  Bay  Stock
Assessment Plan, as developed by  the Chesapeake Bay Stock
Assessment Committee,  in fulfillment of the living  resources
commitment:

   "by July 1988 to develop, adopt and begin to implement
   a Bay-wide plan  for the assessment of  commercially,
   recreationally  and selected ecologically valuable
   species."

The  Plan  proposes  improved means  of  assessing  stocks  of
finfish and  shellfish in  Chesapeake  Bay.    It  identifies
outstanding data needs for stock assessment models for Bay
fisheries.  Recommendations include improved ways to collect
catch,  effort,  and biological data  from  commercial  and
recreational  landings  in addition to long-term  surveys for
estimating relative abundance of  important species in all
regions  of  the Bay   and its  tributaries.    There  are
recommendations  in the Plan for studies of early life  stages
designed  to  examine  natural  and  human-caused  sources  of
mortality and   to   investigate   biological   effects   of
pollution, habitat loss, and disease.

The  data  collected   in the  recommended trawl  and  seine
surveys will  be used by  the  stock  assessment  groups  to
develop short-term  management  related information  and  by
monitoring  groups  to  track  long-term  trends.    Stock
assessment information will also be used  in the  development
of fisheries management plans,  scheduled  for completion for
13 species between July 1989 and 1992.

We agree  to support  the  Plan's  recommendations  for  new
efforts  to  collect  basic,  short  and  long-term  data,
consistent Bay-wide, that are essential for stock assessment
and monitoring.   We recognize the  need to  commit  financial
and  human  resources to  the  task  of  developing  and
implementing the recommendations  of the plan.    Finally,  we
direct  the  Chesapeake  Bay  Stock  Assessment  Committee
annually to prepare reports detailing the  progress made  in
implementing  the plan's recommendations.
                        111

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                        ACKNOWLEDGEMENTS

The development of this plan has been a cooperative effort of
the Chesapeake Bay Stock Assessment Committee (CBSAC)  and its
coopted experts.  The  following  scientists  authored sections
of  the  Plan:  Herb  Austin,   Erik Earth,  Chris  Bonzek,  John
Boreman, Bess  Gillelan,  Dick Hennemuth, Marta Nammack,  Mike
Prager,  Louis  Rugolo,  and  Cluney Stagg.   Chapter  2 is  an
edited version of the soon  to be  released Status of  Stock
Knowledge report which was edited by Herb Austin  and authored
by  members  of  the CBSAC  SOSK working group.   The Plan  was
edited  by  Erik  Earth.   Special thanks  are  due  to  Dick
Hennemuth, Bess Gillelan, and Verna Harrison  for  guiding the
Plan  through  the development and adoption process.    The
remainder  of  the Committee  assisted substantially  through
their review and  comment on  the  Plan.   The  membership of the
committee is as follows:
Members

Dick Hennemuth, Chairman, NOAA NEFC
John Boreman, NOAA NEFC
Bess Gillelan, NOAA EPO
Charlie Wooley, USFWS

Lou Rugolo, Vice-chairman, MD DNR
Steve Jordan, MD DNR
Brian Rothschild, UMCEES CBL

Herb Austin, VIMS
Jack Travelstead, VMRC
John McConaugha, ODU

G. P. Patil, PSU

Marta Nammack, DC DCRA
    Alternates
Chris Bonzek, MD DNR

Cluney Stagg, CBL

Mark Chittenden, VIMS
Erik Earth, VMRC
Cynthia Jones, ODU

Marilyn Boswell, PSU
Coopted Experts

Nick Bolgiano, PSU
Jim Colvocoresses, VIMS
Gerard DiNardo, UMCEES CBL
Ed Houde, UMCEES CBL
Pete Jensen, MD DNR
Mike Prager, ODU
Harley Speir, MD DNR
Kevin Summers, VERSAR
    Liasons

Betty Bauereis, CAC
Kent Mountford, EPA
Bill Rickards, STAC
                          IV

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                      TABLE OF CONTENTS
                                                        PAGE

FOREWORD	iii

ACKNOWLEDGEMENTS	iv

EXECUTIVE SUMMARY	vii
I.   Introduction - Fisheries Management and Stock
     Assessment goals, objectives, and information
     needs	   1
II.  Characteristics of Selected Chesapeake Bay
     Fishery Species 	   5

     American Shad	   8
     Black Drum	   8
     Bluefish	10
     Blue Crabs	11
     Croaker	12
     Eel	13
     Menhaden	14
     Oysters	15
     River Herrings	17
     Red Drum	19
     Spot	20
     Striped Bass	21
     Summer Flounder 	  22
     Weakfish	24
     White Perch	25
     Yellow Perch   	  25
     Other Ecologically Important Species  	  26
III. Approach to Stock Assessment	29
IV.  The Data Collection Programs	35

     Fishery Dependent Data - studying the harvests  .  .  35
     Fishery Independent Data - surveying the
     populations	48
     Recruitment Process Studies 	  55
V.  Implementation   	59


RELATED READINGS 	  66

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                      LIST OF FIGURES

                                                       PAGE

Figure 1.  Status of Stock Knowledge 	  7

Figure 2.  Conceptual Relationships for
           Fishery Models  	 31

Figure 3.  Sample Fish Ticket	43

Figure 4.  Sample Area and Gear Coding
           for Fish Tickets	44

Figure 5.  Sample Species Coding for
           Fish Tickets	45

Figure 6.  Flow of Activity and Responsibility
           for Chesapeake Bay Stock Assessment 	 61



                       LIST OF TABLES


Table l.   Common Gears for Fishery
           Independent Sampling  	   49

Table 2.   Additional Funding Requirements
           to Fullfill Stock Assessment
           Program Recommendations 	   65
                          VI

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                    EXECUTIVE SUMMARY
In  recognition   of  the   important  values  -  economic,
recreational,  ecological,   aesthetic,  symbolic  -  that  are
attributed to  Chesapeake   Bay  living resources,  the  1987
Chesapeake Bay  Agreement   contains  an entire  category  of
commitments related to  restoring  and protecting the  Bay's
living resources.   The  Chesapeake  Bay Stock Assessment Plan
responds to one of these commitments:

By  July 1988,  develop,  adopt,  and begin  to  implement  a
Baywide  plan   for   the  assessment  of   commercially,
recreationally, and selected ecologically important species.

The  Plan  was   developed  by  the  Chesapeake  Bay   Stock
Assessment Committee, a  federal/state committee sponsored by
the National Oceanic  and Atmospheric Administration (NOAA).
Membership includes scientists  and  resource managers  from
Maryland, Virginia, Pennsylvania,  the District  of  Columbia,
NOAA  National  Marine  Fisheries  Service  and  Estuarine
Programs Office, and the US Fish and Wildlife Service.

This summary highlights the conclusions  and recommendations
of the Stock Assessment  Plan.
                        BACKGROUND

Stock assessment  is  the interpretation of  fish  population
data  for describing the status  of  fish stocks  and  for
predicting the results of fishery management options.   Stock
assessment analyses take population  characteristics such as
growth,  mortality,  and reproduction  and relate  them  to
controlling  factors which include  fishing  pressure  and
environmental distress such  as  climatic  fluctuations,
pollution, and habitat degradation.

Maryland, Virginia, and the District  of Columbia have  all
been conducting stock assessments on selected  species,  but
many  of  the  ongoing programs  are limited  in  terms  of
geographic  coverage and  range  of  species.   The  Plan
concludes that  existing  programs  do not  constitute  a
comprehensive  stock assessment  program for the Bay and  its
tributaries.    In  response,   the  Plan  recommends   the
cooperative development  of routine,  systematic  assessments
in conjunction with  cooperative,  long-term  data  collection
programs for the Bay's fishery species.
                        vn

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                     WHAT DO WE KNOW ?

Chapter 2  of the Plan describes present  knowledge of several
representative  Chesapeake Bay finfish and shellfish species.
For  some  species,  such as  menhaden,   there is  adequate
information upon  which  to  make  informed management
decisions.    Other species,  such  as  the oyster,  have not
received the level of attention their importance would seem
to warrant.

For the most part,  the  programs  in  the  Plan have  not been
described in a species  specific  manner,  since it  was felt
that this would be the most effective means  of depicting the
needs  of  stock assessment.   Specific requirements for
individual species will  be reviewed  in a document entitled,
Statusf Trends. Priorities,  and  Data Needs for Chesapeake
Bay Fisheries,  to  be produced during the summer of 1988.
                        DATA NEEDS

In general,  there  is sufficient basic biological  information
for many  species,  but little  reliable  catch,  effort, and
recruitment  data is available.    This  deficiency  is
significant because  these data  are the major  types of
information required for stock assessment analyses.

Stock assessment  data needs include  improved  catch  data,
fishing  effort data,  and biological data  (length,  age,
weight,   sex)  from commercial  and recreational  fisheries.
These three categories are called "fishery dependent" data.

"Fishery  independent"  data are  also  necessary  so  that
unbiased  information  essential  for  stock  assessments is
collected  on  juveniles and  adults.    Fishery  independent
sampling  does  not rely  on  commercial  or  recreational
fishermen for collecting fish and  is conducted through
standardized  surveys, such as the  Maryland beach seine
survey  which is  used to  estimate a juvenile  index for
striped bass.

Short-term intensive  research is  also needed to  understand
the  environmental and biological  processes that affect
growth,  mortality,  and reproduction within fishery stocks.

The  Plan calls  for   baseline  fisheries  data that  are 1)
collected  with  standard   methods  Baywide,   2)  precise and
accurate,   3)  representative  of  the  distribution  and
abundance of Bay species,  4)  inclusive of  all major species
and their critical life stages, and 5)  long-term in scope.
                       Vlll

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            PROPOSED PROCESS  FOR IMPLEMENTATION

Approximately 100  people are  currently  working  on some
aspect of stock assessment in the Bay region at over  twenty
organizations.    Research,   monitoring,   and management
programs that  contribute to  stock assessment  spend about
three million  dollars  per year; most of  these funds ($2.5
million) are administered by  federal agencies,  in particular
NOAA  and  the Fish  and  Wildlife Service.    Coordination of
personnel and  financial resources will be a  key  goal  for
implementing the  proposed Baywide data  collection program
and for conducting stock assessment analyses.

The Chesapeake  Bay Stock Assessment  Committee  (CBSAC)  was
formed  in  1985 to improve  the coordination  of  technical
stock assessment  problems.    The plan recommends  that  the
Committee  continue its  coordination  role  and  begin to
oversee the active development of baywide stock  assessments.

The major features of a Baywide stock  assessment program and
recommended dates of  implementation  are  summarized as
follows.

            Fishery Dependent Programs:  July  1989

Initiate a  Baywide  fishery  statistics  program to provide
improved estimates of catch and fishing effort  for each type
of fishing gear and area of the Bay.

Outline procedures for collecting such data, to include the
implementation of a  trip-ticket  system  for commercial
fishermen and more extensive  recreational fisheries  surveys.

Institute   a  program   for   obtaining  species   and  age
composition, as well as  other biological characteristics of
commercial and recreational catch.

         Fishery Independent  Programs:  Spring  1989

Complete final design for a  Baywide  trawl  survey  to  obtain
fishery independent estimates of abundance  and  distribution.

Augment trawl  survey with other  sampling  methodologies to
obtain  abundance  indices for  species and  life stages  not
captured by  the trawl  survey,  such  as  the  ongoing beach
seine surveys in Maryland and Virginia.

Develop research program to  investigate the effects of the
environment on juvenile fish  and shellfish  populations.

Coordinate these surveys and  studies with the Chesapeake Bay
Program Baywide Monitoring Program.
                        IX

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        Stock Assessment implementation:   July 1988

Chesapeake Bay Stock Assessment Committee  (CBSAC) will  have
oversight responsibilities for Baywide Stock Assessment.

Maintain CBSAC working  group  roles for reporting on  status
of Bay stocks, investigating analytical techniques,  and  data
management.

Establish new stock assessment working  groups on  finfish,
oysters,  and blue  crab  to  begin  immediately with   the
evaluation of available data and proposed sampling programs.

Produce  annual  reports  on the  status of  stocks,   fishery
statistics,  and periodic Baywide stock assessment reports.

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                  CHAPTER  I.  INTRODUCTION

                        BACKGROUND

Maryland  and Virginia  fisheries managers and scientists
began  meeting  informally  in  1979  to  discuss  ways  of
coordinating the  collection of  fisheries  data information,
prior  to  even  the  "Chaffee  Amendment"  of  P.L. 89-304.
Striped bass, shad and blue  crab were targeted at  that time
as  the most important  species.    From these   informal
meetings,  a  Planning Committee  was  appointed  to  formalize
future  efforts.    Consequently,  shortcomings  in   catch
statistics,   recruitment  surveys,  and  data archiving  were
discussed,  and  recommendations   for   achieving  appropriate
Baywide statistical programs.   A  document,  entitled  Report
of  a  Workshop on  Chesapeake  Bay Fisheries Statistics  was
generated, and the recommendations forwarded to the Bi-State
Working Committee, chaired jointly by  the Natural Resource
Secretaries of the states of Maryland  and Virginia,  of  the
Chesapeake Bay Commission.  These recommendations were later
contained in a  1983 report  entitled, Implementation  of
Recommendations  on Chesapeake  Bay Fisheries Statistics,  and
cited  several needs and  recommendations,  relevant to  the
current NOAA  Chesapeake  Bay  Stock Assessment  Program,  and
included:

0    That   Maryland   and  Virginia  develop   adequate,
     quantitative,   and  coordinated  fisheries  data  and
     information systems.

°    That Maryland  and  Virginia design  and  implement  a
     coordinated program  of  juvenile and  adult  monitoring
     and biological  sampling.

0    That  Maryland  and  Virginia develop a  compatible
     automated  data  base management  system  for catch,
     effort, and size distribution.

In  1983,  the EPA Bay  Report  reiterated the  importance  of
stock  assessment  as a  means  of  providing information  on
living  resources  for water  quality,  as well  as  fisheries
management.   The EPA Report,  Governors'  Conference, and  Bi-
State Chesapeake  Bay  Commission  recommendations made  clear
the need for Baywide fisheries stock  assessment.   Action on
the part of the  General Assemblies of Maryland and Virginia,
stemming  in  part from  the  1982  workshop recommendations,
gave mandate  to  the  regulatory and  research agencies  to
develop such programs.  In 1984,  action by the Congressional
delegations of Maryland, Virginia, and Pennsylvania resulted
in the inclusion of  $1.5 million for Chesapeake Bay resource
assessments,  oxygen  depletion  studies  and   fisheries
statistics in the FY85 NOAA appropriation law,  P.  L. 98-411.
As a result, NOAA generated its Chesapeake Bay Study  Plan,
and at the  same time coordinated  the  formation of  the

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Chesapeake Bay  Stock Assessment Committee (CBSAC).  The
committee  is  composed  of  scientists  and  managers  from
Maryland, Virginia, Pennsylvania,  the District of Columbia,
and the  Federal  Government  (NOAA  NMFS,  NOAA  EPO,  and FWS) .
The membership  of the  Committee  reflects the  recognition
that many  of  the Bay's  fishery stocks cross jurisdictional
lines  within  and beyond  the  Bay,  and  that appropriate
assessment can  only  occur  if  the respective jurisdictions
work cooperatively.

The CBSAC Terms of Reference state that it will  undertake  a
program  for  the  Baywide assessment  of  fishery  resources
which  will partition the  effects of  fishing mortality,
natural mortality, and contaminants on variation and trends
in abundance.     Specifically,the  Committee will:

0  identify and describe state and federal stock assessment
   programs;

0  identify and describe additional data collection systems
   needed  to  characterize  the future status of  the stocks
   and explain their  fluctuations;

°  review fishery statistics needs and recommend programs to
   improve the   current  fishery  statistics  collection
   program;

0   plan and integrate  biological  effects  studies with
   stock assessments;

°  recommend research projects; and

°  provide guidance to Sea Grant to insure that low D.O. and
   other biological  effects studies on  fish and shellfish
   are supportive of  stock assessment  studies.

As of 1987, thirty research projects with total funding over
2.7 million  dollars   have  been supported. The  emphasis  in
1985  and  1986   was  on  statistical  interpretation  of
historical data    and on the  evaluation of  various stock
assessment sampling  methods.   The  emphasis  in 1987  was  on
fishery  independent sampling  throughout the  bay,  utilizing
trawling.

The Stock  Assessment  Plan presents CBSAC's guidance for the
development of  a  Chesapeake  Bay  stock  assessment program.
Many of  the  general   recommendations of  the  Plan  have been
presented  in  the past.   Although  positive  steps  have been
taken  on  past  recommendations,   progress  has  been  slow
towards  the development of  cohesive inter- and intra-state
stock assessment  programs.  It  is hoped that the completion
of the plan and the continuation of the  Chesapeake Bay Stock
Assessment Committee will be the catalysts  required to build
a cooperative program.

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The  urgent need for  baywide  stock  assessment  is  also
acknowledged in the  1987 Chesapeake  Bay Agreement  through a
commitment by  the Bay's  jurisdictions which reads:

"by July 1988, to develop, adopt, and  begin to  implement a
baywide   plan   for   the  assessment  of   commercially,
recreationally,   and   selected  ecologically  important
species."

This agreement commitment reaffirms the  need  to develop a
quantitative  understanding  of the relationships between
environment and  fisheries in  order to  understand  how  to
appropriately   rehabilitate the Bay.

          GOALS AND OBJECTIVES FOR STOCK ASSESSMENT

Man's primary  benefit  from healthy  fish,  crab, clam,  and
oyster stocks  is the continued  capability  of  harvest  for
enjoyment,  consumption,  or profit.   From  this perspective,
it  is  the fisheries  manager's  goal  to  assure sustained
harvests.   Likewise,  one of the  goals  of  environmental
management is  to  provide adequate habitat quality to support
living resources, which,  in  turn,  would  provide  sustained
harvests.  In  fisheries management  the optimum  level  of
sustainable harvest  is   determined  through consideration of
biological and socio-economic  factors.   Three  simply  stated
objectives for meeting the goal of sustained harvest are (1)
quantify biologically  appropriate  levels  of  harvest,  (2)
monitor current and  future resource status for comparison to
harvest  objectives,  and  (3)  adjust  resource  status  if
necessary  and   if  possible   through  management.   Stock
assessment is a  process that  will  contribute to  all  three
management objectives.

In the Chesapeake Bay,  the ability  to  accomplish any  of the
three objectives  for meeting  the  goal  of sustained harvest
is  limited by  inadequate knowledge  of  the size  of  the
stocks,  their variability, and the  effects of  fishing  and
pollution on productivity and the recruitment of young fish.
A major constraint with  regard to  materially  improving the
status of stocks is a lack of basic  data  usually  available
for fisheries as valuable as  those  of Chesapeake Bay.   To
rectify  this  problem  it is  necessary  to  define   stock
assessment programs  both  within  and among the  states  that
obtain required data and specifically  address questions
which must be  answered to achieve better fishery and habitat
management decisions.

                 WHAT IS STOCK ASSESSMENT ?

Fishery stock  assessment refers to  the process of  compiling
and interpreting available and relevant information on  the
fish stock in  question.   The objective of this process is to
produce an accurate  statement  detailing  the  status of  the
stock (so far as  the  data allow) ,  to  inform  the  decision-

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maker of  options for  management  and  to  predict  possible
consequences    of   resource    management    strategies.
Consideration  is  given  to the  population  dynamics of  the
stock,  particularly growth, mortality,  and  recruitment
processes,  and  how  fishing  (or  other   anthropogenic
activities)  affects  any or all  of these.  Principal points
to note  about stock assessments  are the  following:    (1)
they are an attempt to describe the status of a  fish  stock
and  the  associated  fishery;  (2)  they  range from  accurate
measures of the status  of a  stock to  subjective  estimates,
and  (3)  they require  fishery, biological  and  sometimes
economic  data,  often  long  time  series,  to provide  the
knowledge base necessary  for fishery  management  decisions.

Using a  liberal  definition  of  stock assessment,  Maryland,
Virginia and the  District of Columbia  have  been  conducting
stock assessments on  a number  of important species.   Many
ongoing programs  are limited in  scope  in terms  of species
and  geographic  coverage  and  are  primarily  geared toward
collection  of  data rather  than  analysis.   With  these
shortcomings it can  be  argued that existing  programs do not
constitute a comprehensive stock assessment  program for the
Chesapeake Bay  and  its tributaries,  neither in  individual
jurisdictions  nor in a  Baywide  context.  A  program suggests
routine, systematic  assessments based on precise  and timely
data.  At the  very  least, these data must include catch and
effort from each  component of  fishing,  and  biological data
to include length-frequency (or age-frequency) and sex  ratio
observations.    For the  most  critical species,  fishery
independent (scientific  survey)  information on abundance and
other stock parameters  will be necessary.

A  commitment  to a  long term,  coordinated  program for  the
collection of these data  is  a  necessary part of  any  stock
assessment  program.    While  the  objective  of  such  a
commitment   may  be   more   closely  aligned   with   the
implementation  (or  potential implementation) of  management
regulations,  the activity   still constitutes  biological
monitoring.    Depending  on  the  management  issues  and
biological    events   involved,   information    from   an
environmental  monitoring program may also be useful in  stock
assessment;   as   such  close  coordination   of   the   stock
assessment and monitoring  programs in  the  Chesapeake Bay is
important.    If  anything  the  coordination  will   avoid
duplication of  effort and   inefficiency,  and  enable  the
collection of  data that would be better suited for analyses.
Close  coordination  will  also  enable  the  collection  of  a
broader range of information  than  would be  possible by each
program individually.    For these  reasons this plan  is
coordinated with the  activities of  the  Chesapeake  Bay
Program.   Furthermore, the  recommendations of  this  plan
concerning  fishery  independent  and  fishery  dependent data
collection  serve as the  basis for  the  component of  the
Chesapeake Bay  Biological Monitoring  Plan  for bay finfish
and shellfish species.

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CHAPTER II.   CHARACTERISTICS OF SELECTED BAY FISHERY SPECIES
Chesapeake Bay fishery resources  may be categorized several
ways according to their  life  cycle,  fishery,  or management
protocol.   Further,  finfish and shellfish are separated in a
similar  fashion.   Of significance  for  management  and
fisheries  alike,  is the  fact  that  there  are  few  finfish
fishery species  that  are year-round Bay  inhabitants.  Even
the  Chesapeake  Bay striped bass,  after  reaching sexual
maturity,  is  a seasonal visitor. Most commercial  and
recreational  finfisheries harvest seasonal transients  that
migrate across  coastal  states'  boundaries  into varying
management regimes.   Managing  and assessing such transients
is far more complex than the  management and assessment  of a
year-round resident.

Some representative  categorizations  are as follows:

0 Anadromous  spawners  vs  ocean spawners vs bay spawners
° Grazers  vs  apex predators
° Commercial  vs recreational vs ecological importance
° Fishery  (pound net,  hook and line, hand tongs)
° Natural  recruitment vs  human-aided  recruitment  (hatchery
  releases,  seed transplants)
° Mobile (crabs)  vs  sessile (oysters)

Generally  management and often assessments, are species
specific.    The  joint gubernatorial  directive  to  develop
Baywide FMP's  is  on  a  species  by species   basis.    This
approach to  management   is pragmatic and  logistic and  is
probably the best current system to use.   Attention  should
also be directed to  the possibility  of developing management
plans for  multi-species  fisheries by gear  such as  the  pound
net.   Further,  the  non-harvested stocks  of  ecological
importance such  as  the bay anchovy, silverside,  killifish,
opossum  shrimp  (mysid),  and  grass  shrimp  should  be
candidates for  management.   The  Bay Program has focused,
since its  inception, on the habitat; and  while  the fishery
managers need to concentrate  their energy  on  control of the
harvest to effect management,  they  must  not  lose sight of
the  importance  of  the habitat.   Clearly  in an  estuarine
system    resource    management   by    habitat-resource
characterization is  also  a viable alternative.

The CBSAC  stock assessment plan  is a combination of fishery
dependent  and  independent assessment programs directed
toward  providing   data   and  information in  support  of
management.    Non-species  specific  trawl  surveys  and
commercial/recreational  catch  sampling  provide data  for
assessment models and  FMP's.  While  stock assessments are

-------
needed for these  broad  species groups,  (e.g.  the  ocean vs
bay  spawners,   pound  net  catches,   or  commercial  vs
recreational  harvest),  in the final analysis,  questions are
directed to the  status of stocks for individual species.

The  1983  EPA Bay Report   described stock  fluctuations in
anadromous and ocean spawners in  an initial  attempt to look
at cause  and effect of  the  trends in these  two "groups".
The concept of grouping these stocks ecologically according
to  spawning  areas  is  sound,  and has  a  rationale  that
supports management.  Ocean spawned fish may prove harder to
manage  than  the  Bay or  river spawned  species,  as  their
recruitment  and  harvest  are more  strongly  influenced  by
events outside of the Bay.   Riverine species,  on the other
hand, spawn where Bay state  managers have the potential to
control both the environmental  quality  and harvest pressure.

Habitat  requirements  are a neglected  categorization of
fishery resources.   Recruitment processes  described above
are different even though anadromous and ocean species are
taken in the same nets at the same  time. Anadromous spawners
are influenced by river  flow  and rooted plant detritus forms
the  basis  for  their   food  chain.    Abundance  of  ocean
spawners,  on the other hand,  is influenced by offshore shelf
wind shifts and these spawners derive  their  energy from the
pelagic phytoplankton.

The  Chesapeake Bay  Program Living Resources Task  Force
developed  a  habitat characterization  report  in  1987  that
identified our  status   of  knowledge  on  resource habitats.
The  identified  gaps were   many   and  should  provide  the
rationale  for  future research efforts on habitat-resource
requirements.  A  concurrent  effort by the  CBSAC Status of
Stocks  Knowledge Work Group  identified  the  types  and
sufficiency   of  our  knowledge   about  the   biology  and
population dynamics  of  the Bay species.   The  body of this
report is  contained  in  a species  matrix (Figure  1)  and a
bibliography.

An  examination  of the  matrix  shows  that for  some species
(e.g. menhaden)  there is adequate information upon which to
base informed management decisions.  Other  species such as
the  oyster have  not received the  level  of  attention their
importance would seem to warrant.   Further, the matrix shows
that  for  most  other   species we  have  sufficient  basic
biological information,  but  that in the  area of population
dynamics and catch/effort data  little is  available.  This is
a  significant omission  as they  are  the parameters  in the
various dynamic population models needed for the management
decisions.   Indeed,  it would appear  that  another  way of
characterizing or categorizing species  would be by our  lack
of knowledge.

-------
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               ACCCPTACUE STATE OF KNOWLEDGE


               SIGNIFICANT PRCKIRESS MAOC
ANALYSIS UNDERWAY


NO ANALYSIS
FIGURE  1.    STATUS  OF  STOCK  KNOWLEDGE
                  (CBSAC  SOSK  WORKING  GROUP,
                  JAN  1988)
1   | NO DATA


PJTI NOT APTLICA«L£


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|~PC1 UNDER DEVELOPMENT

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An annual assessment of the status of  the  Bay stocks is an
objective of  CBSAC.   This will  be contained  in  an annual
Status  of Stocks  (SOS)  report  patterned  after the  NEFC
Status of Stocks Report produced  since  1976.   The SOS report
will  include  both a  biological  status  of the  stocks,  an
analysis  of  the fishery  during  the  previous year, and a
report  on  the  status  of  our  knowledge.    The  status
descriptions  for  several  important  species  that  are
contained  in  the  SOS report  follow  on the  next   several
pages.
            AMERICAN SHAD,  Alosa  sapidissima

The  American  shad  (Alosa  sapidissima Wilson)  is  an
anadromous member  of  the herring family  which ranges from
southern Labrador to northern Florida  on the Atlantic coast.
Its  spawning  and nursery grounds are  located in  estuaries
and  rivers.   Shad rear  in  their river of birth for their
first  summer,  then migrate  to  the  ocean,  and eventually
return  to  their natal  rivers to  spawn   about  three years
later.

The  American  shad has  been  a  popular and  heavily fished
species valued for its  flesh and roe  for  at  least the past
two  centuries  in  Atlantic  coastal areas.   Shad catches
peaked  in  Maryland in  1890,  then declined until  1942.   A
period of  relative  recovery  in  the   1950's  followed,
especially in Maryland.   However, by 1980  stocks  in Maryland
were so low the fishery in Maryland was closed indefinitely,
with reported harvests having decreased from  184,221 pounds
in 1971 to 14,319 pounds in 1979. While such  a  catastrophic
reduction  in  catch (and presumably abundance)  has not yet
occurred in Virginia, the  trend  in  catch  over the last ten
years has been downward.  From NMFS  surveys the  recreational
landings were 61 and 65 percent  by weight  of  the commercial
catch  on the  Atlantic  coast  in 1965 and  1970  respectively.
If   the   1965   and   1970   surveys   are   approximately
representative,  it is obvious that sportfishing for American
shad has been significant.

There are no reported results of standard  production, yield-
per-recruit or  stock-recruitment models  for  American shad
for  the Chesapeake Bay.   To be meaningful,  these models
require data  that currently  does not  exist   for Chesapeake
Bay.


                 BLACK DRUM,  Poqonias  cromis

The black drum,  Pogonias cromis (Linnaeus), ranges  from Nova
Scotia south through the Gulf of Mexico to Argentina.  It  is

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most abundant along Texas, but is common  along  the Atlantic
coast from Chesapeake Bay to Florida.   The black drum is the
largest member  of  the family Sciaenidae  along  the Atlantic
coast, attaining a maximum weight of 66.28 kg (146 Ibs).

Black drum enter coastal waters of Virginia  during early to
mid-April, presumably migrating from offshore areas south of
Chesapeake Bay.   Recreational fishermen begin to catch black
drum during early to mid-May in the lower portion of the Bay
and throughout  the Bay  as the season  progresses.   Adults
migrate southward and offshore by late fall.

Larval black  drum  utilize tidal  currents to enter nursery
areas  located in the  mid to upper  marsh areas  throughout
Chesapeake Bay.  Juvenile  black  drum have been reported to
enter  Chesapeake  Bay following the  adults  and  disperse
throughout the Bay.

A question still  exists  as to whether  black drum  spawn in
Chesapeake Bay.  A 1961  paper stated that spawning did not
take place  in Chesapeake  Bay because  no larval  black  drum
were  found.    A later study  identified black  drum  eggs
obtained  from Chesapeake  Bay  near Cape  Charles  City,  but
failed to delimit the area of spawning.   They concluded that
spawning  occurred  along  the  seaside  of  Virginia's Eastern
Shore  and the  mouth  of  Chesapeake Bay.    Ripe  males  and
partially spent females  were  observed  in  Virginia  waters
during spring and early summer.   This led to the conclusion
that  spawning probably took  place near  the  mouth of  the
Chesapeake Bay.   Spawning apparently occurs from early April
through mid-June,  when  water  temperature  is  about  17.5°C
(63.5°F).

Black drum from the Gulf of Mexico reach maturity by the end
of their second year, at standard lengths (SL) of 285-330 mm
(11.2-13.0 in).  Age at maturity  of  black  drum  is unknown
from  along  the Atlantic  coast.    Fecundity  data  for  this
species is lacking as  well; however, a  1929  study estimated
that a ripe female 1.1 m (43.3 in) in total length  (TL)  from
the Gulf of Mexico contained approximately 6,000,000 eggs.

Commercial landings of black drum  in Virginia have averaged
approximately 30,000  pounds  for  the  past  fourteen  years.
Prior 1972,  landings for the Chesapeake Bay area ranged from
60-481,000 pounds.

The increased popularity  of  black drum as  both a  food and
game  fish has  brought  this  species  to  the  attention  of
various regulatory agencies.   A minimum size limit for black
drum has  been set  by the VMRC at 16 inches  TL.   Commercial
harvesters and  buyers  are required to submit daily harvest
information to the VMRC,  and anyone buying,  or  catching and

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selling  black drum  are required to obtain a  Commercial
Harvest Permit.
               BLUEFISH,  (Pomatomus  saltatrix)

The bluefish (Pomatomus saltatrix Linnaeus)  is a migratory,
pelagic species which is distributed worldwide in the shelf
waters of  temperate  and warm-temperate latitudes.   In the
western Atlantic it is found from Nova  Scotia  to the Gulf of
Mexico, and  is particularly common in  the  Middle Atlantic
Bight especially from spring to fall.   Bluefish are ravenous
carnivores that prey on a wide variety of invertebrates and
vertebrates throughout the water column.

Most bluefish mature by two years of age; males perhaps at a
smaller comparative weight.   Sex ratios of spawning stocks
are approximately equal, as  they  appear to  be at all other
life phases.  Evidence suggests that two principal spawning
populations  of bluefish  exist  along  the  Atlantic  coast.
Spawning occurs over the "open shelf"  and larvae develop in
surface  waters.   Major  bluefish  spawning  sites  in the
Chesapeake Bight are located offshore over the outer half of
the continental  shelf,  where water temperatures  are  22° C
(72°F) or  greater and  salinities  are  31  ppt  or greater.
Initiation of  spawning,  as well  as  daily activity and
swimming speed are determined  in part by  temperature and
photoperiod.   Year  class  success is postulated to  be
dependent  on  the circulation  of  the  continental  shelf
waters; vertical or geographic position in the water column
determine when and where eggs and larvae are  transported.

Bluefish exhibit  complex  migratory patterns  which  are not
well  understood;  apparently major  differences  between the
migratory  routes  of  the  two principal spawning  stocks do
exist but  further  knowledge  on  migratory patterns  is
limited.    Reported commercial catch of bluefish  along the
Atlantic coast dates to 1880.  The  peak reported  commercial
catch  for the Atlantic coast was  about 21 million pounds in
1897  which  was followed  by a period  of  low harvests.   A
trend  of increased catches that began in 1960 was succeeded
by  significant increases  in the mid-1970's,  but reported
harvests have  since  stabilized or declined slightly.  From
1970-1982, reported Maryland commercial catches ranged from
1-6 percent  of the reported Atlantic  coast  total of  4,715
tons  (annual  average); Virginia  catches  ranged  from  10-40
percent.

Historically,  the  recreational catch  of  bluefish has been
many  times larger than the commercial  catch;  since 1960, the
average  distribution  of removals along the whole Atlantic
coast  is estimated to have been 12 percent  commercial and 88
                      10

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percent  recreational,  based  on reported  commercial  and
estimated recreational catch.   From  1979-1982, the estimated
Chesapeake Bay  recreational catch  was  36  percent  of  the
estimated mid-Atlantic bight recreational  catch,  which was
in turn  52  percent of  the estimated  total  Atlantic coast
recreational  bluefish  catch of  59,421 tons  (annual average).

During the 1970's,  a  small quantity of  bluefish  was taken
annually  by  foreign  fishing  vessels  (472,000  pounds
maximum).   Currently, bluefish may  not  be retained by
foreign fishing boats.  The Atlantic bluefish  stock(s) seems
to have  increased in abundance in  the past ten  years.
Evidence for an increase is based on the large increases in
both reported commercial  and  estimated  recreational catch,
and  on the  results  of Northeast   Fisheries  Center   (NEFC)
surveys,  in which abundance indices  (number  of fish per  tow)
have generally increased during the  same  time  period.

Since  1979,   the  MAFMC  has  been  developing  a  bluefish
management plan for the Atlantic coast stock(s),  and since
1985 the ASMFC has been working on  one for their interstate
management.    The  plan  allocates 20 percent  of  the total
projected bluefish catch for a given year to  the commercial
fishery,  10 percent of  which  will  be  allocated to the New
England  area,  50 percent to  mid-Atlantic  area,  and 40
percent to the south Atlantic area.
            BLUE CRAB,  Callinectes  sapidus

The blue crab is a common inhabitant  of  near-shore waters of
the Atlantic coast from New Jersey to Florida and along the
Gulf Coast.  The  Chesapeake  Bay  is the  center of abundance
and  produced 82.9  million  pounds  of  hard  crab,  and 2.7
million pounds of peeler and  soft crab with a total value of
$31.2    million  in 1986.  This  compares with total average
annual Bay hard crab landings  of 75  million  pounds at $5.9
million  from 1960  to   1970.   Not  only  do these  numbers
account for over half the total landings for the entire east
coast,  but  the  Bay also  provides  almost  all  the United
States supply of soft crabs.
Blue  crabs  mate  in brackish  water,  generally mid-spring
through   summer,  during   which  time  they   are  called
"doublers".   After mating,  the  females make their way down
the Bay to the higher salinity waters near the mouth of the
Bay where they overwinter.   The males remain year-round in
the lower salinity waters further up  estuary.  During winter
when temperatures are below 8° C (47° F), blue crabs bury in
the mud  or  sandy bottom.   It  is   at  this time  that the
females  in  the  lower  Bay are  taken by the  winter dredge
                      11

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fisheries.  Females carrying eggs  are called  "sponge crabs",
and the eggs are extruded and hatch  from mid-Spring through
summer.  At first the larvae swim  feebly  in the near-surface
waters, but  later descend  to  near-bottom  waters.   In the
surface waters  they  are susceptible to  being  swept out of
the Bay, but once  in the  bottom waters are transported up-
Bay in the estuarine circulation of the "salt wedge".

The blue  crab  may live three years,  but most  only survive
two years.   Females mate  when one year old  during  their
terminal  molt,  and  after  spawning  they neither  molt nor
grow.    From May  through  September  in their  second summer
they are captured and sold as peelers.  Late  in their second
summer both males and females generally  reach  5  inches
carapace width, the  legal minimum size in Virginia.  Sponge
crabs  are protected when  they enter  the 130  square mile
"crab  sanctuary"  at  the mouth of the  Bay from  1 June - 15
September, but may be harvested outside the sanctuary.

Prior  to  the 1940's  baited  trotlines were the main fishery
in  the Bay.    Since  then almost  all hard crabs have been
taken  in baited crab pots,  with the  exception of  the winter
dredge fishery  in  Virginia  that comprises   some  15% of the
Bay catch.   The recreational catch  is undocumented but is
believed  to  be  large.   Peelers  are captured  by scrape,
"peeler pots",  or a staked  net  called  a  "peeler pound".
Peelers are sold as bait for recreational fishing or held in
floating cages until they molt and become soft crabs.

Management of  blue  crabs, whether by  state  or bistate
regulation will  be  difficult,  as  the natural environment,
more so than the  spawning adult population  size,  plays the
dominant   role   in   establishing  year  class  success.
Consequently, with the primary factors regulating stock size
not under the  control of  fisheries managers,  effective
fisheries management may be difficult.


      ATLANTIC CROAKER, Micropogonias undulatus

The  Atlantic  croaker is  a medium-sized  member of the
Sciaenidae family and ranges from  Massachusetts to Mexico on
the North American coast and  from Surinam  to Argentina on
the South American  coast.   The species  is  most  abundant,
however, along the southeast coast of  the United States and
in  the northern Gulf  of  Mexico.    The Atlantic   croaker is
iridescent overall,  greenish silver  above and silvery  white
below.  Numerous brassy or  brownish  spots form oblique wavy
lines  on the upper sides and back.

Adult  croaker tolerate a wide range of temperatures, 2-30°  C
(35-86°  F)  and  salinities   (0-35  ppt),  but  the  juveniles
                      12

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prefer the lower salinity and  oligohaline environment of the
estuaries which  serve as  nursery grounds.  Adult croaker,
like other sciaenids,  spawn in the waters of the continental
shelf during the late summer and fall of their second year,
but  return  to the  estuaries  during the  following spring.
Spawning occurs  from  August  through  December off  the
Chesapeake Bay and south  to Cape Hatteras.
Although estimates vary,  reported size  and age at maturity
suggests that  Atlantic  coast  croaker  are  sexually  mature
when 3-4 years old.   The smallest reported mature male and
female  were  24  cm  (9.5  in)  TL  and 27.5  cm (11  in)  TL,
respectively.  Eggs and larvae drift toward land until they
are able to actively swim towards land and  estuarine nursery
areas where they remain until  the following fall.

Atlantic croaker are believed to reach  a maximum age of 7-8
years when they are >500 mm (20 in)  TL.   The  species feeds
on   polychaetes,   mollusks,   mysids,   decapods,   other
invertebrates, and occasional  small  fish.

The croaker is one of the most  freguently caught  species  in
estuarine and nearshore  waters,  particularly  from March  to
October.  Maryland and Virginia have generally accounted for
the  majority  of the  Atlantic  coast croaker  harvest.   The
Virginia catch has varied  from  a high  of  25,000  mt in 1945
to a low of 3 mt in 1968, peaking again  in  1977 with a catch
of 3,900 mt  before  dropping once again.   The 1986 harvest
totaled only 1,034 mt.

Maryland's landings show a similar  trend,  but the relative
catch was much smaller,  the largest  catch being 2,260 mt  in
1944.    The  1984  harvest  totaled  only  12   metric  tons.
Maryland currently  imposes a  10  inch minimum size for the
species.  The Mid-Atlantic  recreational catch, recorded
since  1979,  declined between  1979-1980,  but  has  since
steadily increased to 3,426 mt in 1984.

The  abundance  of Atlantic  croaker seems  to be closely
related  to  climatic  trends  and  fishing pressure.   Warmer
temperatures  appear  to  favor  the species  as evidenced  by
increases  in landings during  the  first  part of the 20th
century.  Between 1958 and  1971,  increased  fishing pressure
and  cold winters reduced  the Atlantic  catch  to  <3,000  mt
from 1961-1973. Subsequent increases and decreases in catch
after  1973  seem to be correlated with  fluctuations  in the
fishing  effort  and general temperature trends during that
period.
            AMERICAN EEL, Anauilla rostrata

The  American  eel,  Anquilla  rostrata  (Lesueur)   is   a


                      13

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diadromous species  found in coastal  waters from  Greenland
and  Northern  Canada  to  the Gulf  of  Mexico and  the  West
Indies.   The  species is also  widely  distributed  in  inland
waters, including the Great Lakes, the Mississippi drainage
as far as South Dakota and  west to  the Rocky Mountains.

American eels are believed to spawn between  Bermuda and the
West Indies,  in the vicinity of the Sargasso Sea.   Spawning
occurs from February through June.   The larval stage  eel  is
called a leptocephalus. During the  leptocephalus stage,
which lasts one or two years, currents distribute the  larvae
in an  apparently  random  manner along the Western  Atlantic
Coast.   Transformation from  the leptocephalus to  the  glass
eel  stage is complete by  the  time   eels  reach  the  coast.
After arriving in coastal regions they gain pigmentation and
are  then  called  elvers.   Within a  few months elvers  enter
the  yellow eel  stage which lasts  until  sexual  maturity  is
reached 5 to possibly 18  years  later.

At the present time,  eels  are  not a  desirable recreational
species, but commercial  fisheries  are carried out  for  both
elver  and yellow eel  stages.    In many  areas,  elvers  are
trapped and used for stocking lakes and reservoirs.   Yellow
eels  are widely  used as  bait in  the blue crab  trotline
fishery  in Chesapeake  Bay,  and in recent  years  a  live eel
export fishery has developed.  Although the  American  eel  is
an  important  commercial  species,   catch  statistics  are
probably not a reasonable indicator of actual harvest  levels
because of a lack  of reporting requirements and because  of
the  nature of the  fishery  itself.   For example,  statistics
for  the  elver  fishery  are  not  available, and only  crude
estimates of the yellow eel harvest used  as bait  in the blue
crab fishery exist.


        ATLANTIC MENHADEN,  Brevoortia  tvrannus

Atlantic menhaden, or bunker, is a member  of the Clupeidae,
or herring family.  Although very similar to the  alewife and
shad  in  appearance,  menhaden are  distinguished  by a  mouth
lacking teeth,  and a dorsal fin located between the anal and
pelvic  fins.   The body  is bluish  above  and the  sides are
silvery  with a  reddish  tint.    A dark   spot  followed  by
several smaller spots is  present on the shoulder.

Atlantic menhaden are a  euryhaline species inhabiting bays,
sounds and estuaries  from  Nova Scotia,  Canada to  West  Palm
Beach, Florida.  The species travels in dense schools  of 50-
200,000  fish  and  makes  extensive   north-south coastal
migrations.   In  the spring,  menhaden  travel  north  with
larger,  older  individuals  moving  further  north  than  the
younger, smaller fish.  During the  autumn, Atlantic menhaden
                      14

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migrate  southward  where  they are  usually  intercepted  by
fishing fleets off  North Carolina.

Spawning occurs in different locations throughout the year.
Menhaden become  sexually mature usually  between age  1  (8
inches) and age 2  (10  inches)  with  all capable of spawning
by the third year.   Fecundity estimates range  from 38 to 631
thousand eggs  for  each female.   The  eggs  float freely and
hatch  at sea,  and  wind and  currents  carry  the larvae into
sounds and estuaries where the young spend their first year.
Phytoplankton and zooplankton  serve as  the major  food
source.  Menhaden   are an  important  forage for mackerels,
Atlantic bonito,  bluefish, striped bass, and weakfish.

Although not  a desirable recreational catch,  menhaden have
been  caught  by commercial  fishermen  since  the mid-1800's,
and reports  of their  importance to  the  earliest colonists
are freguent.  The stock  is  concentrated in different areas
along the Atlantic  coast at different times  of the year, and
the fishing fleets  follow them as they move.

Menhaden are  caught by pound nets  and gill nets year-round
in  the  Chesapeake  Bay.    The  use  of  purse seines  is
restricted.  No purse  seines are allowed in Maryland; while
Virginia allows them,  but only between the  third Monday in
May and the third  Friday  in  November.  Each year commercial
fishermen land more Atlantic menhaden than any other fish in
the United States.   Since 1969,  landings  in the Chesapeake
Bay - Mid-Atlantic region have varied from 150,000 metric
tons  (mt)  in 1975  to  283,000  mt  in  1980 when purse seine
landings in  this   region  represented  70%  of the  total
Atlantic menhaden harvest.  Since 1980, the  Chesapeake Bay -
Mid-Atlantic catch  has averaged 240,000 mt.

Stock assessments in the Bay are conducted by  NMFS-Beaufort.


        AMERICAN OYSTER, Crassostrea vircfinica

The American  or  eastern oyster,   Crassostrea  virqinica.
builds intertidal reefs in higher salinity waters along the
entire  east  coast  of  North America  from  the  Gulf  of St.
Lawrence  to   the  Yucatan  and  West  Indies.    In estuarine
locations,  where lower salinity water provides some refuge
from predation, deeper subtidal reefs or "rocks" are common.
Such  oyster  rocks  are  present throughout  the  shallow
portions of  the  Chesapeake  Bay and  its  subestuaries.   The
genus Crassostrea is notable  for  its tolerance  to  wide
ranges of  salinity,  temperature,  turbidity and  oxygen
tension.

Oysters are characterized by lateral compression of the body


                      15

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and the  division of  the  shell into  two halves  (valves  -
hence  the term  bivalve)  separated  by  a  non-calcareous
ligament.  The valves  are  unequal  and have no  hinge teeth
(except in the larval  stage).   The  typically  bivalve foot,
byssus, and anterior adductor muscle are either much reduced
or missing.  Only the  posterior adductor  muscle remains in
the sessile,  attached adult  form.

The genus  Crassostrea  is characterized by  variably  shaped
(ecomorphic)  shells.   The  adult usually rests  in  the left
(cupped)  valve;   however,  in  dense  reefs,  oysters  often
orient   vertically  with   both  valves  pointed  upward.
Internally,  the  mantle extends to the margins of the shell.

Ecological and physiological data  suggest  the  presence of
several physiological "races" of Crassostrea virginica along
the eastern coastline of North  America.   Such  "races" have,
however,   been   actively  mixed  through  fishery-related
transplanting for at least  a century — especially so in the
Chesapeake Bay.   In experimental  culture,  C.  virginica has
been shown to  hybridize with C. rhizophorae.  the mangrove
oyster, and C.  qigas. the Pacific oyster.

The oyster is dioecious  (separate sexes)  but  also exhibits
protandry  and  protogyny (ability to  change  sex,  male to
female  and female  to male, respectively).   Oysters  can
mature sexually at 2 to 3 months of age, usually in response
to increased temperature and availability of food.  Spawning
is stimulated  above a temperature which  characterizes  the
aforementioned "race"of origin.  This  temperature  may vary
from 17  to 25° C (63-77° F)  and increase progressively for
more southerly "races."

Fertilization is  external.   The  planktonic  larvae  are
typically    bivalve,   filter   feed   predominantly   on
phytoplankton,  and remain in the water column  for 2-3 weeks
depending  upon  salinity,  temperature and  food conditions.
Larval  behavior is complex  and  suspected to  play  an
important  role in retention in  estuarine and coastal waters
and selection of substrate  for  settlement and metamorphosis.
Larvae exhibit gregarious settlement and specificity to hard
substrate. These  behavioral  traits  are  central to  the
maintenance   of   oyster  reefs  or  "rocks"   as   distinct
biological and geological features.

Adult filter feeding activity is influenced by temperature,
salinity  and sediment  load.    A large  oyster  can  filter
several  liters  of  water  per  hour.    Consequently,  oyster
reefs  or  "rocks"  are major  components  of  sedimentary
processes  in estuarine and  coastal systems.

Historically, the oyster reefs  of the Chesapeake were  much
                      16

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more  extensive  than present  day.   Inadequately  controlled
exploitation  followed   by  decimation   and  essential
elimination of significant Chesapeake Bay oyster stocks  in
higher   (>   20   ppt)    salinity   seawater   by   MSX   (a
haplosporidium,  Minchinia nelsoni)  after 1960  has left  a
resource that is  only  a  fraction  of  its  original  size.
Continued  intense  disease and  fishing pressure  present
little  hope  for  expansion of  the  resource  in  the near
future.

The market oyster season  in Virginia and Maryland runs from
1 October through 31 March.  A market oyster in Virginia  and
Maryland is 3" long.

Both  Maryland and Virginia have  extensive  monitoring  and
research programs directed at  understanding  oyster  biology.
In  spite  of these  efforts,  little is  known  about  the
population  dynamics  of  the  stocks  as they relate   to
management.    While  oyster  biology  shows  a degree   of
similarity Baywide,  there are  many  differences even between
river systems. To be effective,  management will have  to  be
on a river-by-river basis.
             ALEWIFE, Alosa pseudoharengus
            BLUEBACK HERRING, A. aestivalis

The alewife,  Alosa pseudoharengus. and the blueback herring,
A.  aestivalis.  are  anadromous  members  of  the  family
Clupeidae,  and collectively are referred  to as alewife  or
gaspereau  in  Canada and  as  river  herring  in the United
States.   In both  countries the  commercial  landings  are
reported  as alewife.    Collective  reference to the  two
species stems from  similarities in  their  appearance,  times
of spawning, methods of  capture,  and the  juxtaposition  of
spawning grounds.   The commercial catches are used primarily
for bait,  pet food, fish meal,  and  in Canada,  a substantial
portion  of the  catch  is  salted and exported  for  human
consumption.   Small, local  markets  exist  for  smoked  river
herring and fresh or canned roe.

The  alewife  and  the  blueback herring  have a largely
sympatric distribution.    Alewives  occur from  Labrador  and
Newfoundland to  South Carolina, while blueback herring  range
from Nova Scotia and northeastern New Brunswick to Florida.
Adults are generally distinguished at capture  on  the  basis
of eye  diameter,  body depth,  and   peritoneum  color.    The
diameter of  the  alewife  eye  is larger  than  the  distance
between the tip  of the snout to the forward edge of the eye,
but  the two  measurements  are  about  egual  in  blueback
herring.    The alewife  body tends  to be  deeper,  and  its
peritoneum is pale  (pearl-grey  to  pinkish white),  sometimes
                      17

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with dusky spots  (melanophores);  in  contrast,  the blueback
herring peritoneum  is black  but sometimes  soot-grey  with
darker spots.

The  onset  of  river  herring spawning  is  related  to  water
temperature;  thus, it varies with latitude,  and it may vary
annually by 3  to 4  weeks in  a  given locality.   There is
considerable  overlap  in  the  spawning seasons  of the  two
species.  Spawning for alewife  generally begins between 5 to
10°  C and for blueback herring,  between 10  to 15°  C.
Alewives begin to spawn  3 to  4 weeks earlier than blueback
herring, but their peaks  of spawning  differ by  only  2  to 3
weeks.  In the Chesapeake Bay  region  the  onset of spawning
is about mid-March in Virginia  streams and the last of March
in Maryland streams.   Both  species  return  to  sea shortly
after spawning.

When spawned in  flowing  streams,  river herring eggs (after
the  loss  of  adhesiveness)  and larvae  are   transported
downstream.    In Chesapeake  bay tributaries,  juveniles
(young-of-the-year)  are distributed  widely throughout tidal
freshwater nursery  areas in  spring  and early  summer,  but
subsequently  move upstream  in  summer  with  the encroachment
of saline water.   With decreasing water temperatures in the
fall  or  early  winter, the  juveniles  move  downstream  as a
first stage of their seaward migration.  Some juvenile Alosa
will remain in deep estuarine  waters  through the winter.

First spawning by river herring  occurs  from ages 3  to 6,
with the composition  of  virgin spawners strongly dominated
by age 4 fish.   In general,  spawning  stocks  of river herring
are  comprised of  ages 3  to 8.   Males tend to dominate age
classes  3 to  5,  while  females live longer and,  thus,
dominate the  older age classes.

The male to female ratio throughout  a season tends to favor
males,  about  2:1.   Male  domination  of the sex  ratio is
probably due to  a greater  proportion of  males maturing at
ages 3 and 4.   Males tend to dominate in the early runs, but
the   proportion   of    females   increases    (sometimes
significantly)  in the later runs.

There is considerable variation  in the mean lengths at age
reported  for river herring.    Part of the variation is
undoubtedly natural, but part  is  due  to different methods of
back  calculating  lengths at age.   In general,  females of
both species  are  larger  than   males,  and alewives  are
somewhat  larger  than blueback  herring.    Most  reported
maximum total  lengths range from 12.1-13.7  in  (310  to  350
mm) .

Very  positive  contributions  to   freshwater  ecosystems  can
                      18

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result from the presence of river herring.   All  life stages
of  both  anadromous  and   landlocked  river  herring  are
important forage for many freshwater and  marine  fishes and,
in  addition,  birds,  amphibians,  reptiles and mammals  have
also been documented as predators.  Due to  mortality on the
spawning  grounds,  anadromous  alewives  were shown  to  be  a
nutrient source to a system rather than just a mechanism for
nutrient  regeneration.
               RED DRUM, Sciaenops ocellatus

The red drum, Sciaenops ocellatus, is one  of the 22 members
of the drum family known for the drumming or croaking sounds
produced by vibrating  their  swim bladders.  The  species is
also known as channel bass, puppy drum (juveniles),  spottail
bass,  and  redfish.    They  are  silvery-gray  overall with  a
coppery cast.   One  or more  black spots  are present at the
base of the caudal fin.  The species  is  also recognized for
the subterminal mouth and the lack of barbels on the chin.

Red drum range  from  Massachusetts to Key  West,  Florida, on
the Atlantic coast but are not common north of  New Jersey.
They also inhabit the  Gulf of  Mexico  from  the  southwest tip
of Florida to Vera Cruz, Mexico.

Spawning takes  place in nearshore ocean waters  near passes
and  inlets.   On  the Atlantic  coast  spawning  may  begin as
early as July and continue through December, or  possibly as
late as mid-February,  peaking  in  late  September  or  October.
Sexually mature males  are  18-20  in.  (age  1+,  470-530mm FL) .
Females mature  at ages II  and III or 23-30  inches  FL   (575-
760mm FL) .

Problems with  age determination  techniques have prevented
documentation of the maximum age  for red drum.   An  estimate
based on banding patterns on  otoliths, however,  suggested  a
maximum  age of 33 years.

Crabs, shrimp,  fish  such as striped mullet, spot,  pinfish,
and pigfish  compose  the majority of  the  diet of adult red
drum.  Smaller  individuals less than  3  in (75 mm)   SL feed
mainly  on  small  bottom  invertebrates and  other  juvenile
fish.

Maryland-Virginia red drum  are  commercially  harvested  in
estuaries and  ocean  water  in  a mixed  species   fishery  by
several gear types.   These include haul seines, fish trawls,
pound nets, gill  nets,  hand  lines and trammel nets.   Pound
nets and fish trawls have  claimed the majority of  red drum
caught in Virginia since 1977.  Most of the  fish  are landed
between May  and  October in  Virginia and year-round  from
                      19

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North Carolina to Florida.  The recreational fishing season
in the Chesapeake Bay lasts from late  April  to November.   In
Virginia,  recreational  landings exceed  the  commercial.
Current regulations in this state prohibit the possession  of
more than two red  drum greater  than  32 inches total length
or any less than 14 inches TL.

Data on commercial landings of red drum have been  collected
since 1880 with  Atlantic  coast  landings being  consistently
lower than those of  the Gulf  of Mexico.   Red drum  landings
reached 83 mt in 1950.  With the  exception  of 2 years,  1965
and 1983, Virginia landings have not exceeded 9 mt  over the
past 20 years.
                 SPOT,  Leiostomus xanthurus

The  spot  is  a  member of  the Sciaenidae,  or drum  family,
which   inhabits   estuaries   and  coastal  waters  from
Massachusetts to Mexico.   They are distinguished  from  other
sciaenids by the lack of chin barbels and by  their  silvery-
gray body and 12-15 dark  lines extending from  the  dorsal  fin
to the lateral line.  A prominent black  spot  about  the size
of the eye is located behind the  gill  cover.

During the summer,  spot  are found in shallower waters from
Delaware to  Georgia.   Later in  the year they tend  to move
offshore onto the  shelf  edge  from Cape Hatteras  to central
Florida  where they remain throughout  the winter.  Spot
generally tolerate  a wide  range  of  salinities (fresh  to  37
ppt) and temperatures 2-35  C  (35-95  F) ; however,  long cold
spells are known to cause extensive mortalities.

Spot  spawn  at  sea in  the  fall and   winter when  water
temperatures  are  between  59-79   F,  although  the  spawning
season is  extended from  September through November  off  the
Chesapeake Bay.  Most individuals on the Atlantic coast  are
sexually mature  by  the  end  of  their  second year or  the
beginning of  the third year when they are 186-214  mm  (7.0-
8.5  in)  TL.    Data on fecundity  are  scarce,  but fecundity
estimates  for spot 158-187 mm   (6.0-7.5 in)  SL   range from
77,730-83,900.   The estuaries serve  as  nursery grounds  for
the larvae.  As they mature, the  juveniles move up into less
saline or  fresh water  where they  remain throughout  their
first winter.

Spot grow  rapidly  during  the  first  year attaining  a length
of  132 mm.    Their  reported maximum  age  is   IV  in  the
Chesapeake Bay and V near  North Carolina.   They  feed on  a
variety of foods such as crustaceans,  polychaetes, detritus,
and small fish.
                      20

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The  spot is  a  popular  catch  for both  recreational and
commercial fishermen.   A migratory species which travels  in
large schools,  the  spot is especially  accessible  to  pound
net  harvest  by  commercial  fishermen.    Landing statistics
since 1930 reflect  great fluctuations  in  the  harvest.   In
1952, landings  of spot  reached  a  high  of 14.5 million  Ibs.
but have since  varied between  3.9 million and 12.7  million
Ibs.  The greatest proportion of the commercial catch  comes
from the Chesapeake Bay  and South  Atlantic regions,  although
since 1960  the  South  Atlantic states  have  dominated the
fishery.

In  1949, the  Chesapeake  landings  reached 8.7 million  Ibs.,
fell sharply  in the 1960's, and peaked  at 6.4 million  Ibs.
in  1970.   Maryland and  Virginia  landings  in  1985  totaled
44,000  Ibs. and 737,000  Ibs.,  respectively.   The  estimated
recreational   catch  along the entire Atlantic  coast ranged
from 13.3 million Ibs.  in 1980  to 4.1 million Ibs.  in  1984.
Spot are one  of the species that  can be  adequately  sampled
by a trawl survey.

There is no  minimum  size  limit  for  spot in  Virginia  or
Maryland.
            STRIPED BASS,  Morone saxatilis

The striped bass  (Morone  saxatilis Walbaum)  or rockfish  as
it  is  commonly called in  the Chesapeake Bay  region is  an
anadromous species which  ranges from the St.  Lawrence River,
Canada  to  the  St.  John's River,  Florida on  the  Atlantic
coast.  Striped bass spawning in Chesapeake Bay occurs  from
April to June at  (or near) the surface  in fresh or  slightly
brackish water. Peak  spawning activity is observed  between
15°  C  and  20°  C;  however,  salinity,  turbidity,  and
temperature,  as well as other factors affect egg  and larval
survival.   Rockfish assemble  in small groups before  age two
and thereafter generally  travel in  schools.

Little  migration  out  of  the bay  occurs in  striped  bass
before 3 years of age.  Tagging studies and age composition
data  from  the coastal fisheries indicate  that most  female
striped bass migrate out of the Chesapeake Bay at about age
3;  conversely,  in Maryland,  relatively  few males ever
migrate out  of the region.   The  coastal migratory  stock,
believed to be typically  dominated  by rockfish  of  Chesapeake
Bay origin, apparently moves  along the Atlantic  coast  from
New  England  to North  Carolina.    Movement  is  generally
seasonal:   north in spring, south in autumn.

The  coastal  migratory  stock  of  striped  bass  has been
characterized by  the  periodic entrance of  a dominant  year
                      21

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class  into the  fishery.   The  last  such year  class  in
Chesapeake Bay  occurred  in  1970  and  resulted  in  peak
commercial landings  in  the  coastal  states in  1973.    The
reported commercial  and  recreational  catch data,  CPUE and
the Maryland juvenile index  all  indicate  that striped bass
abundance  in the  Chesapeake  Bay has  suffered  a continuous
decline since 1973.  The decline in landings  since 1973  is
probably  attributed to a  combination  of  three  primary
factors:   (1)  natural fluctuations,  (2) overfishing, and (3)
degraded  water  quality,  including  pollution  and   loss  of
spawning habitat.   Maryland  juvenile  index  data  indicates
that mortality  in  the  fishable stock may have  increased
since the early  1970's, which may explain the observed shift
in landings from 4 and 5  year olds to  2 and 3 year olds.
A coastwide management plan for striped bass  was adopted by
the Atlantic States  Marine Fisheries  Commission (ASMFC)  in
1982.   The ASMFC suggested  that  states  enforce a  14 inch
total length minimum size  limit on striped bass  in inland
waters,  and a 24 inch total length minimum size  limit on the
coastal fisheries.   The  plan  further urged  that  major
spawning  areas or  rivers be  closed  during  the  spawning
season.

By  1987  the  amendments to  the  plan called for a  95%
reduction in mortality of  1982  year class   females and
subsequent year  classes until  such  time as  95% of the
females spawned.  This resulted in a 24" Bay/31" ocean size
limit in Virginia, and a 6 month closure to fishing (June -
November). In 1984, based largely on the relentless decline
in catch,  reduced abundance of spawning females, and eleven
years of  below  average   reproduction,   Maryland  initiated  a
striped bass moratorium effective the  beginning  of 1985.

Currently, there are  several  positive  signs  of  stock
recovery.   In Maryland, the number  of  4 year old female
spawners  (1982 year  class) sampled  on the spawning grounds
in 1986 was  greater than any year  since  sampling  began in
1982.   However, indices  of egg deposition exhibited only a
slight upward trend in 1986,  and  the number of older females
was found to be decreasing.   A  larger  percentage of the 1982
year class will be mature in the spring of 1988 and will be
joined  by  spawners of other year  classes which  have been
protected.

The  Maryland  juvenile striped  bass  index of  4.8   improved
slightly  in  1987,  but was still  less than the  long term
historic average of 8.8  (the  Interstate Fisheries Management
Plan established  a  3 year  running  average  of  8.0  as one of
the criteria that signals reproductive recovery).  According
to the  Maryland  Striped  Bass Annual Report,  a  continuation
of  the  Maryland  striped bass  moratorium  will afford the
current  female  spawning  stock,  and   those that  will
                      22

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eventually become  mature,  the  protection  from  fishing
mortality  which  they require.    In  Virginia the  juvenile
index continued to show  an  upward  trend since reaching a low
in 1980.

Adult striped bass are assessed when on the spawning rounds
in Maryland using gillnets,  and  in  Virginia  from  poundnet
catches.  Juvenile abundance  is  estimated each summer during
directed young-of-the-year  seine surveys in each state.
            SUMMER FLOUNDER,  Paralichthvs dentatus

The  summer  flounder is  a commercially  important  flatfish
species  that  generally ranges  from Cape  Cod  to  northern
Florida, with occasional capture north  of Cape Cod.   During
the  late spring to  early  fall,  adults  are  found in coastal
and  estuarine  waters,  to  as shallow  as  1 m.   Decreasing
water temperatures and  changes  in photoperiod cue the annual
fall migration of fish north of Chesapeake Bay to offshore
spawning and wintering grounds  on the middle and  outer
portions of the continental shelf respectively.  Fish south
of Chesapeake Bay spawn  and  overwinter on the  inner/middle
continental shelf.

Reproductive data from  specimens collected  on 1974-1979 NMFS
bottom  trawl surveys  between  Cape Cod and  Cape  Lookout
indicate that most spawning  occurs  between October  and
February.  Fish north of Chesapeake  Bay spawn from September
to December, whereas fish  south of Chesapeake Bay spawn from
November to February.

Eggs rise to the  surface  and are  presumably transported by
wind driven surface  currents.   Winds from  the  NW  to NE are
believed to cause  the  successful   transport  of  larvae  to
estuarine nursery habitats.  It has  been suggested that the
major nursery  areas are  in Virginia  and  North  Carolina.
Juveniles  seem  to  prefer mesohaline/polyhaline  nursery
areas,   where maximum growth  rates  occur.   Juvenile summer
flounder remain in  estuarine and  coastal  waters until ages
2-3.

Summer  flounder  are fully  recruited to  the commercial
fishery  at  ages  2-3.    The  optimal age  at  entry to  the
fishery is 5-7  years for females and 4-5 years  for males.

Commercial  landings  in  Virginia increased  significantly in
1973 and have remained  at a relatively  constant level since
then.   The  increase  in  landings  may  have  been due  to
increases  in  fishing  effort  and  fishing power  in  the
offshore trawl  fishery.    Commercial   landings  in  Maryland
also increased  in  1973  and remained at  a  higher  level
                      23

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through 1979.   Landings  decreased substantially between 1981
and 1986.  Recreational  catch data,  though not as extensive
as  commercial  catch data,  indicates  that 45-70%  of total
U.S.  summer flounder  landings can be  attributed  to  the
recreational fishery.    The recreational  fishery has  the
potential  to  significantly  impact  the  commercial   fishery
(coastal and offshore) because  it catches younger  fish prior
to their recruitment to  the commercial  fishery.  The  minimum
size limit in Virginia and Maryland  is  12 in  (30.5 cm).

Young  flounder  are first  sampled  in  trawl  surveys  during
their second year.  Young-of-the-year which inhabit  shallow
vegetated areas are not  susceptible  to  trawling gear.
              WEAKFISH,  Cynoscion  reqalis

The  weakfish,  Cynoscion reqalis.  also known  as  the gray
trout  or  squeteague,  is  a  member  of the  drum  family,
Sciaenidae,  so  named for  the  drumming sounds  created  by
vibrating the  swim bladder.   The  body  is  elongate and
moderately compressed, olive above and silvery on the  sides
and underside.  Dark blotches  mark the upper body in oblique
wavy lines.  The dorsal  and caudal fins are dusky, while the
ventral,  anal,  and  margin of  the  caudal  fin  are   bright
yellow.   Two  large  recurved teeth are present in the  upper
jaw.

Weakfish  are  found  in coastal waters from southern Florida
to Cape Cod,  Massachusetts, but  are  most  abundant from New
York  to  North  Carolina.    With  rising  water temperatures
during  the spring,  weakfish  migrate  northerly  and inshore
into  bays, sounds,  and estuaries.    During  the  fall and
winter, the  younger  weakfish  less than  4  years  old move
offshore  and  south,  often as  far south as  Florida,   while
older  fish move further offshore and  only as  far south as
North Carolina.

Spawning, hatching,  and  larval  development  occur  in
nearshore  and estuarine waters  between March  and October
with peak production between late April and June.  The mouth
of  the  Chesapeake  Bay  is   the  major Virginia-Maryland
spawning  ground.  Weakfish grow rapidly and are reported to
reach  a maximum  age  of 11  years old (approximately 11.6
pounds).   Males reach sexual  maturity when approximately  1
year  old  or  5-6  inches (130-150mm)  SL, while  females are
slightly   larger  (145-190mm  SL  or  5.7-7.4  in)  before
attaining sexual maturity.   The species  is also  highly
fecund: a female 500mm  (19.7  in)  TL  may  produce  over two
million eggs  at one  time.   Young gray trout feed primarily
above the bottom  on mysid  shrimp  and  anchovies, while older
individuals  feed throughout  the water  column mostly on
                      24

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herrings,  anchovies,  silversides, other fish,  and blue
crabs.

Weakfish are a  valuable  commercial and recreational sport
fish found along the United States east coast.   Commercial
catch  statistics  indicate that weakfish  landings have
fluctuated widely,  increasing from  a recent low of 1,397 mt
in 1967 to  16,293  mt  in  1980.    Recreational  landings also
peaked in  1980  at  21,064 mt.    In Virginia the  commercial
catch dropped from  6.2 million pounds in 1980  to  2.0  million
pounds in  1986.   The Maryland  landings suffered a  similar
decline from 568,000  pounds  in  1980 to  173,000  pounds in
1986.

Results  of  a  weakfish  stock  assessment  indicate that
weakfish   from   Maryland  to  North   Carolina   may  have
experienced both  growth and  recruitment overfishing in
recent years: however, these conclusions are  uncertain due
to weaknesses in the data set used  in the  analyses and lack
of knowledge of  weakfish  stock structure.


             WHITE  PERCH, Morone americana

The  white  perch  (Morone  americana  Gmelin)  is a semi-
anadromous  schooling  species  found primarily in shallow,
brackish  waters,  and  ranging  from Nova Scotia  to South
Carolina.   It is most abundant  from the Hudson River  to the
Chesapeake Bay.   This species is  both adaptable and  broadly
tolerant and hence  is  capable of dominating fish  communities
in both fresh and estuarine waters.

White perch  migrate  upriver  to areas  of  low salinity for
spawning  after  overwintering  in  deep,  saline  waters.
Spawning occurs  from late March through June, and has been
found to peak at temperatures around 10  C in Chesapeake Bay.
Following  spawning,  adults move  downstream to  brackish
waters  in  the  middle  and  lower  estuary.    Within  the
Chesapeake Bay,  young  white  perch  move  progressively
downriver as they develop from  egg  through  juvenile  stages.
Evidence  suggests  that  environmental factors  including
temperature,    fresh   water   flow,   dissolved   oxygen,
competition, and predation  are  related  to  survival of white
perch   larvae   and  early   juveniles   and   subsequent
establishment  of  year-class  strength.    The young grow
rapidly during  their first  year,  often  reaching 40%  or more
of their  maximum size.   This rapid growth of white perch
combined with production  of large numbers of offspring and a
wide environmental  tolerance range has  allowed the  species
to rapidly colonize new environments.

Historically,  the  white  perch  has  been  an important food
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fish  in  the Chesapeake  Bay region.   Annual  landings  are
perpetually variable  apparently  due largely  to climatic
conditions.
            YELLOW PERCH,  Perca flavescens

The yellow perch, Perca flavescens.  inhabit  cool  water  lakes
and  reservoirs,  coastal  rivers,  streams and  low  salinity
estuaries from  Canada  to South  Carolina.   They have  6  or
seven  vertical  black bands  extending across  the back  and
yellow to bright red pelvic  and anal fins.

Males are sexually mature at  2 years of age,  or  about 5  in
(12.7 mm) long,  and  females at  3 years  or  6  in  (15.2 mm).
Spawning occurs  in  shallow  water between March  and April.
A female may release from 3  thousand to 150  thousand eggs at
a time.  The eggs are deposited in a gelatinous strand  which
is left among vegetation and submerged branches.

Yellow perch may live up to 13 years  and attain  a weight of
4 pounds,  but most  are small and  only 5-8  in  (13-20  cm)
long.   Their diet  is  largely composed of benthic insect
larvae, leeches, amphipods,  crayfish,  and small fish.

The yellow perch is a valuable sport  and commercial species
which  is primarily  encountered on its spring  spawning run.
The commercial fishery is centered in the upper Maryland  Bay
and  freshwater  reaches  of  the  main-Bay   tributaries.
Commercial landings have undergone a  dramatic  decline  since
the  1880's when  Maryland  landings were estimated at over 1
million  pounds.   In 1985 Maryland  landings had  dropped  to
only 43,000  pounds.  There  are no minimum  or maximum size
limits in Maryland or Virginia at this time.


              BAY ANCHOVY, Anchoa mitchilli

The bay  anchovy  (Anchoa mitchilli Valenciennes)  is  a widely
distributed engraulid,  found in  coastal, estuarine  and
freshwater habitats  along the Atlantic  seaboard from Cape
Cod to Yucatan, Mexico.  Bay  anchovy  is  one of the  most
abundant  fish  species  in  its range  and   probably is  the
single most abundant fish in  Chesapeake Bay.   It is a  small
species with a maximum  size not  exceeding 110  mm (4.33  in),
and  individuals larger than  90mm (3.54 in) are uncommon.

There  is no  commercial  or recreational   fishery  for  bay
anchovy.  Its small  size  and habit of aggregating  in  small
schools  make  it  an  unlikely  target  for future fisheries.
However,  bay  anchovy  is  an  important  forage  species  for
predator  fishes throughout   its  range.   Predators  include
                      26

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striped bass, bluefish, weakfish and  summer  flounder.   Bay
anchovy  primarily  feed on  zooplankton  and  thus are  an
important  link between primary  producers  and harvested
predator   species  in  many  ecosystems,  including   the
Chesapeake Bay.

Male and female bay  anchovy  mature at age 0+  when 35-4Omm
(1.4-1.6  in)  in  length.    Spawning  season  varies  with
latitude,  being more protracted  in  the southern part of its
range.   Most spawning  in the  Chesapeake  region occurs  from
mid-May through mid-September.   Spawning  occurs over a  wide
range of salinities  and temperatures  (15-30  C) .   Eggs and
larvae are  abundant  in both shelf  and  estuarine  waters.
They are  the most common  component  of the  Chesapeake Bay
ichthyoplankton in  summer  months.    Larvae hatched  in May
probably mature and  spawn  by  mid-August,  based on reported
larval growth rates.   Larvae that occur  in  Chesapeake Bay
tributaries tend to  be transported  upriver.  Entrainment and
impingement of young bay anchovy in power plant intakes  is a
problem in the Chesapeake and  other estuaries.

Causes  for  interannual  variability  in  abundance   and
recruitment are little known,  primarily because bay anchovy
is  not exploited.    Long-term  trawling  surveys  in  the
Virginia part  of the  Chesapeake  Bay and  egg and  larvae
abundances  indices  in Maryland  have  suggested major
fluctuations  in  yearly  abundance.    Unlike  more  northern
estuaries where bay  anchovy migrate offshore  in  winter and
have variable return rates  the following spring,  Chesapeake
Bay populations overwinter  in the  Bay.   Abundance of mature
individuals in the Chesapeake region  apparently  is highest
in  late  summer  (August-September)  when  new   recruits
predominate.

The population  dynamics are  relatively  little understood.
Bay anchovy  is short-lived;  length-frequency and  otolith
(ear bone)  analyses  indicate  that  maximum age probably  does
not exceed 3+ years.   Few  individuals attain  two  years  of
age.  Adult mortality rates seldom  have been  estimated.   In
the Delaware Bay during 1983,  annual mortality was estimated
to  average 80.2%,  based  on  mean daily rates.    Fishery
assessment models  have not  ,been  applied because the species
is  not  exploited.    Considerable  literature,   both  in
published form and reports, is available  on the dynamics  of
bay anchovy populations exposed to power  plant entrainment
and impingement  effects.
              KILLIFISHES, Fundulus sp.

The  killifishes,  principally  the  common  killifish,  F.
heteroclitus,  and  the  striped  killifish,  F. maialis.  are
                      27

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common marsh and  tidal  creek nearshore species  in the Bay
and  its  tributaries.    They inhabit  areas  that  are often
oxygen  deficient  in summer and  exhibit  large  seasonal
temperature extremes.   During winter  they bury in the mud.
Spawning occurs during the spring on the spring tide.  Eggs
are deposited above the normal high tide where they  develop
and hatch the next month on the high spring tide.   Killifish
are omnivorous and are one of the most common  forage  for the
blue, crested night,  and green herons.


         ATLANTIC SILVERSIDE,  Menidia  menidia

The  Atlantic silverside,  and  its cousin,  the  Tidewater
silverside, M.  berelina.  are common species along  the entire
Mid-Atlantic coast.   The Atlantic  silverside  is  common in
higher  salinities,  and  the Tidewater  silverside  in lower
salinities;  below  5 ppt  only the  Tidewater  silverside is
taken.    In the  Chesapeake Bay   these  two  species  are
important  forage  for  bluefish,   striped bass  and  weakfish.
They support no commercial  fishery  but are  one of the most
important  ecological  species in the  Bay.    The  silverside
spawn in the spring, laying demersal eggs that are attached
to shoreline grasses.   They grow rapidly  reaching 60-80 mm
(2.5-3  in)  by  the  end  of the first summer,   and after
spawning the  following  spring (April-May)  reach  100 mm (4
in) before they die at 14-16 months of age.

In spite of  their  ecological  importance they  have not been
studied as extensively as many other Bay species.
                      28

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         CHAPTER III.   APPROACH TO STOCK ASSESSMENT
Chapter I describes general  data needs for stock assessment;
Figure  1,  a  summary of present knowledge,  accentuates  the
many shortcomings in present data  collection in the Bay and
tributaries.    To, remedy  these  shortcomings,  CBSAC  has
devised a Baywide data  collection  program  for  fishery
assessment and  management  (Chapter  IV) .   In  that program,
long-term monitoring programs  are  supplemented with shorter-
term  surveys  and  special  studies when  needed to  clarify
stock characteristics.   Data collection and analysis provide
the  basis  for  regular  assessments  of the  status  of  each
fishery.   The assessments,  in turn,  help define  the  data
that must be collected.
             THE NEED FOR VALID LONG-TERM DATA

The most  basic data needs  of  stock assessment  (Figure  1)
include  (1)  knowledge of  stock  identity  in a  biological
sense; (2) estimates of growth  and  mortality rates;  and (3)
catch and effort statistics by age and area.   For valuable
species (especially short-lived species such as  blue crab,
to which some stock assessment  models are less applicable),
fishery  independent  indices of recruitment and spawning
stock size are also essential.

Necessary characteristics  of  data  for management include:
(1)  regularitv--timely.  periodic,  and continuous  data
collection  using standard equipment  and  procedures;  (2)
precision and  accuracy  in sampling  and  recording;  (3)
representativeness  of  the  data,  usually obtained  through
control of sampling regimes; (4)  inclusiveness  of the range
of  stocks throughout the Bay and  tributaries,  and  (5)
temporal  continuity,  the  collection of  long  series  of
regular data over many years.

The pressing need for temporal continuity in the data arises
from the  life histories of  the  resource organisms.   Most
exploited species in  Chesapeake Bay take two to ten years to
reach  sexual  maturity,  and then  produce  only  one  new
generation each  year.    (Hence  the  expression  "yearclass"
refers to  a generation.)   Lengthy  life  cycles  mean  that
detailed  insight  into population  dynamics  (of which  an
important component is variation  in yearclass strength)  can
come only  from analysis of  data collected  over  years  and
decades.
                      29

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                 PERSPECTIVES ON MANAGEMENT

Fishery  assessment  and management  in Chesapeake  Bay have
often  been directed at  single stocks;  however,  several
species  (and therefore several stocks) are often taken in a
fishery, even when only one species  is targeted.  Assessment
of multistock  fisheries  generally  begins,  but  should not
end,  with a thorough understanding of each component  stock.
Sufficient progress  has been made  in multistock assessment
techniques to make them useful in management.   Use of these
approaches appears  to be  a logical  step  for contemporary
fishery management in Chesapeake Bay.

Ideally,  fishery  managers  regulate  fishing  to  obtain the
optimum sustainable benefit from the  fishery.   This optimum
necessarily  considers both biological  and socioeconomic
factors.   However,  the  history  of fishery  management
includes  numerous   cases  of   stock   collapses   when
socioeconomic considerations were allowed to overrule sound
biological advice.  The collapse of the California sardine,
the striped bass and American shad stocks of Chesapeake Bay,
the  Georges  Bank  herring,  the  Pacific  mackerel,   and the
Atlantic salmon should speak clearly to us.
           TYPICAL MODELS OF POPULATION DYNAMICS

In  formulating scientific  advice  for  management,   fishery
scientists often employ mathematical models of fish  stocks.
Although any  model  can only approximate  the  dynamics of a
living stock, the models described  below  contribute  greatly
to our ability to understand population dynamics, formulate
objectives,   and  estimate  the  risks  and   benefits  of
management strategies.

                 Surplus Production Models

The goal  of  surplus production models  is to  determine the
maximum sustainable yield  (MSY)  obtainable from a stock or
group of stocks.  The model is based on a dome-shaped  rela-
tionship between  equilibrium  yield  (the  amount  of  harvest
that can be balanced by growth and  recruitment) and  fishing
effort  or  stock  size.    The  model's  results are  used to
regulate effort  or  harvest.   In  the example  shown  (Figure
2A) , fishing effort at point A results  in equilibrium  yield
(labeled "catch")  of  A'.   To maximize yield,  the  fishing
effort is set at B, since any other effort level results in
lower  equilibrium  yield.   Overfishing occurs  at  point C,
where  increased  effort  results in lower yield.    In an
unmanaged fishery,  fishing  effort  tends  toward excess; in
this example, effort in an unmanaged fishery might be  at C,
and the quantity B'  -  C'  would  represent  lost potential
yield.
                      30

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FIGURE 2.   CONCEPTUAL RELATIONSHIPS BETWEEN  (A) CATCH

           AND EFFORT/ (B) EFFORT AND YIELD-PER-RECRUIT,

           AND (C) STOCK AND RECRUITMENT  (FROM ROTHSCHILD

           ET AL, AN ACTION PROGRAM TO DEVELOP A MANAGE-

           MENT SYSTEM FOR CHESAPEAKE BAY FISHERIES,
           UMCEE8-CBL-84-7)
          I
          o
          o
B'

C'

A'
                    ABC
                      FISHING EFFORT
          CC
          O
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          I
          t_
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                      FISHING EFFORT
                       ADULT STOCK
                      31

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Problems  with   surplus  production  models  include  the
difficulty of knowing whether one  is above or below MSY, the
need for long series  of data (preferably over  10 years and
including years of sharply different population sizes), and
statistical difficulties due  to variability in the data.

Surplus production models  require, at the least, time series
of  catch  and effort  data.   In  addition,  time  series  of
abundance  can  be  used  to  improve  their reliability.
Although catch  statistics are  recorded  for many species,
neither effort nor abundance  is regularly measured for most
Bay species.

                    Dynamic Pool Models

Since  recruitment  fluctuates unpredictably from  year to
year,  a common  management tactic is to  maximize yield per
recruit; ie.,  to obtain the maximum yield in weight from any
level  of recruitment.   With  knowledge of  a  stock's growth
and mortality characteristics, maximum yield per recruit can
be obtained by regulating fishing mortality and the minimum
age  (or size) at  capture.  In Figure  2B,  a minimum size of
14" gives the maximum  yield  per recruit; either  a 12" or a
16" minimum reduces the yield.   The  optimal  fishing effort
for a  chosen  minimum  size is also obtained.   Regulating a
fishery for maximum yield per recruit  (or its variants) can
increase yield substantially, especially for  relatively
long-lived species.   However,  since the model does not
control  the level  of recruitment,  the stock can  become
overexploited,  even  at optimum  yield per  recruit.   The
solution to this dilemma is to employ the dynamic pool model
together with methods (or  extensions of the basic method) to
monitor and control stock size.   Another difficulty is that
the minimum size that provides optimum yield per recruit may
be unacceptable for socioeconomic  reasons.

Dynamic pool models require  timely  estimates of growth and
mortality rates.  These elementary data are  not  well known
for most species in the Bay (Figure 1).

               Virtual Population  Analysis

Virtual population  analysis  (VPA) allows the  scientist to
retrospectively estimate recruitment and population size by
analyzing age-specific catch  data  from preceding years.  VPA
can  provide  relatively accurate  and  precise  estimates of
population size.   These,  in  turn, can be used  as input to
other models and to clarify the  interpretation of  such  other
models.  VPA requires a medium to  long-term series of  catch-
at-age data.   Unfortunately,  age-structured catch data have
been  collected  for  only   one  or two  species  in  the Bay
(Figure 1).
                      32

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             Models of Stock  and Recruitment

Although tremendous  variability  tends  to  obscure  the
relationship, each year's recruitment is  influenced  by the
spawning stock  size;  i.e., the  number  of  parents.   A
simplified model of such a relationship  is  shown in Figure
2C.   In management,  it  is  crucial to  conserve sufficient
spawning stock to  ensure the stock's persistence;  this  is
best  done  through -knowledge  of  the  stock-recruitment
relationship.  Stock-recruitment models can  also provide  a
framework for  evaluating the effects of  external  factors,
such as  climate or habitat quality, on  fish  stocks.   These
models require medium- to long-term sets  of  stock  size and
recruitment estimates, which  are not now available  for most
Bay species.

                       Other  Models

CBSAC  has instituted several  retrospective  analyses  of
Chesapeake  Bay  fishery  data.    Preliminary   conclusions
indicate  that  statistical techniques  such  as Box-Jenkins
times  series  analysis  and  categorical  regression may  be
useful, especially as they can easily include  environmental
factors  that  may affect  stock dynamics.   In addition,
fishery  scientists  are  constantly  refining  and adding  to
their  collection  of  population  dynamics models.   However,
the usefulness all models depends on the type and quality of
data available.
                        CONCLUSIONS

It  is clear  from the  above discussion  that  (1)  fishery
scientists have developed a respectable repertoire of tools
(models)  for the provision of scientific advice to managers,
(2)  the  data  needs  of  these  models  are  quite  well
understood,  and (3) any  model requires regular and prolonged
sampling to produce useful results.   It is  also clear that
past data collection  in  the Chesapeake  Bay region has often
lacked  the qualities  needed:  regularity,  precision  and
accuracy,  representativeness,  inclusiveness,  and  temporal
continuity.    The sampling  plans  described  in   Chapter  IV
of  this  document  represent  attempts   to  improve  this
situation.

Since most models require several years'  worth  of data,  it
will be  a number of years  after  the  initiation  of  appro-
priate   data   collection  programs  before  a   complete,
analytical  stock  assessment  can  be  achieved.   In  the
interim,  stock assessments will rely primarily on historical
information.   As new  information is added and modeling tools
developed, the  reliability of  assessments  will  increase.
During this phase of assessment development,  the data that
                      33

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have  been  collected  in Chesapeake  Bay  over past  decades
should be made available  for the best  possible  analysis by
the fishery  science  community as  a  whole.    Although  these
data may have many shortcomings,  their analysis is necessary
to provide insight into the  dynamics  of our valuable living
marine resources.    Finally,  it  is  important to  emphasize
that  data  collection  and  stock  assessment  activities  are
best  partitioned  by  biogeographic,  rather  than  political,
boundaries.   Fish /stocks are not  restrained by state lines;
stock assessments can provide the  best  information if  their
data and analyses are similarly extensive.
                      34

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           CHAPTER IV.   DATA COLLECTION PROGRAMS
The   previous  section   emphasized   the  importance   of
appropriate  data collection  to  the process  of  stock
assessment.   Many of the problems  associated with  our
present  assessment  capabilities  are  caused by  inadequate
data.   The  following  three  sections  on  fishery dependent
programs,  fishery independent programs,  and recruitment
process studies will  detail the  type of improvements in data
collection programs that  are necessary for stock assessment.

Fishery  dependent  programs  rely  on  the monitoring  of
commercial and recreational fisheries to determine trends in
abundance,  as  well  as  describe  the characteristics  of
fisheries.      Fishery   independent   programs   utilize
statistically designed  surveys  to  collect  the  data used  for
studying the  dynamics of  fishery  stocks.   Investigation of
recruitment  processes  is  accomplished  through  short  term
research  projects  and   is   intended   to  improve   the
interpretation of  statistics  collected by  longer term
programs.  As such, all three programs should be viewed as a
complementary and comprehensive means  of monitoring fishery
resources of the bay.

For  these  data  collection   programs  a  discussion   of
techniques is presented.   It  is important  to emphasize that
data collection programs will only be successful if they are
supported by appropriate  data  management and analysis.   The
implementation chapter  of  this plan  (Chapter 5)  will discuss
the  integration  of data   collection,  management,  analysis,
and documentation.
             FISHERY  DEPENDENT DATA COLLECTION

For the purposes of  discussion,  fishery  dependent  programs
for commercial  and  recreational  fisheries will be  treated
separately.   Although data needs  for both types of fisheries
are essentially the same, the techniques for data collection
are dramatically different due to the  difference  in number
of commercial and recreational fishermen.   (There are on the
order  of  10,000   commercial   fisherman  and  1,500,000
recreational  fishermen fishing  the  bay  each  year.)   This
difference,  as  well  as  other  reasons,  requires  different
approaches  to  collection  of  statistics for commercial  and
recreational  fisheries.
                     35

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               Commercial Fishery Statistics

Commercial fishery  statistic programs involve the collection
of the following four types of data:

°  Catch;  meaning the amount of  fish caught,  including fish
   killed  and discarded during capture.

°  Effort; meaning,  admeasure of  the amount  of  time  and gear
   used to catch the fish.

0  Biological parameters; meaning measures of length,  weight,
   age and sex of harvested fish.

0  Dockside value;  meaning  the amount of money  paid  to the
   fisherman for his catch.

Catch, effort,  and biological data  are  among  the  primary
inputs for most stock assessment models.  Catch, effort, and
value data are the  primary  basis for making many management
decisions.

For  both  stock assessment  and  management  the   yearly
statewide  or regionwide estimates must be  disaggregated by
gear  type, time (month or  day)  and water area.    Many
classical  stock  assessment  models  do   not  require
disaggregated estimates  of  catch and effort.   However,  the
ability to describe distribution is a necessary component of
predictive  and simulation  models.     For  management,
disaggregated  estimates  are  absolutely necessary  for
evaluation of  social  and economic  effects  of proposed
regulations.

Within the  limits  which  allow for collection  of necessary
information, a commercial fishery statistics program should
impose as  little burden  on the  industry  as possible.   An
unobtrusive system  will have the best  compliance and least
possible economic impact.  Compliance will also be increased
by  using  a  system which  becomes  a  routine  part  of  the
industry's practices.

Implementation  of an   adequate  statistics  program  is
dependent  on  the  appropriate  legal,  regulatory,  and
licensing  structures.     Management agencies must have the
authority  to collect the required  information,   to keep it
confidential,  and  to  provide penalties  when  data   is  not
supplied.   Without  an adequate licensing system,  it would be
next  to  impossible to organize  a  good  fishery statistics
system.  An ideal  licensing system would  require that each
gear  type to  be licensed and  each individual would be
licensed separately for  each gear type  fished.   For the bay
region, adequate authority and  licensing  structures  exist,
however compliance and  enforcement still pose difficult
                      36

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problems that must be faced.  The  implementation  of  revised
harvest reporting procedures  will  offer a good  opportunity
for  emphasizing  improved  compliance  with reporting and
licensing laws.

Estimation of numerous variables in an accurate,  precise and
timely manner, by species, year, month, day, water area and
gear   type  involves  tradeoffs   among  some   desirable
characteristics.  , For  example, a system  which  estimates
landings nearly in "real time"  (as is necessary when quotas
are involved)  will  not  be as accurate  or precise as  other
systems; or a  system  which  produces disaggregated estimates
will be more expensive than one  which  produces  only a yearly
estimate.  For Chesapeake Bay fisheries,  the  highest priority
for stock assessment  and  management  is to design a  program
which will accomplish the following:

°  Estimate  landings  and  effort  by  species,  year,   month,
   gear type and river system.

0  Estimate  economic  value by  species,  year,  month,  gear
   type and river system.

0  Estimate  length  composition of the  catch  by  year and
   month.

Additionally, it may be necessary  to develop  capabilities  to
develop more timely estimates.  For some fisheries, year-end
estimates are probably sufficient;  for others,  month-end are
required;  and  for  fisheries under a strict  seasonal  quota,
estimates at  the end of each  week or  even  day would  be
necessary.

Measurement of Commercial  Catch, Effort,  and  Biological Data

This section describes the  units  in which each of the data
types  should  be collected.    In some cases,  the units are
apparent  (such  as dollars  for dockside value)  while  others
may be  less  so.   In  some  cases,  the  best units  may  change
over time and space.  Effort  data  is the  most  complex,  with
several different measures of effort being possible for each
of several gear types.

Landings Estimates
These  data  are typically collected in  units  of  weight
(pounds)  or  volume  (bushels)  for  commercial fisheries and
numbers  for  recreational  fisheries.  Annual  conversion
factors between  weight and  numbers  should  be  established
from biological sampling of the  catch.

Effort Estimates
For the most part, the  required units are specific  to each
gear type.   For  some  fisheries  and  some  analyses,  labor
                      37

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units such as man-days or boat-hours may be sufficient, but
not ideal.   The  suggested "best" units  for  each gear type
are as follows.

0  Gill  nets -  net  type  (anchor,  drift,  stake) ,   length,
   depth, thread  size  and time  fished,  by mesh size, for
   each day.

°  Pound nets - mesh -size of  lead and  pound, length  of  lead,
   and number of hours  between catches.

°  Fyke nets, fish pots,  crab pots - mesh size  and number of
   hours between catches.

°  Haul  seines  -  length  and depth  of  net,  smallest mesh
   size, number of hours  fished and number of hauls  per day.

°  Dredges (oyster,  crab,  clam). scrapes  -  size/weight of
   gear and hours fished  per  day.

°  Hand  tongs.  patent  tongs.  rakes  -  number  of  gear and
   hours fished per day.
o
   Divers.  by hand - number of hours.

   Trotlines  and  long lines  - length  of  line,  number  of
   baits, hours fished per day.
0
   Purse seines - vessel size,  length of nets.

0  Otter trawls  - width of  mouth,  cod  end  mesh size,  tow
   duration and tow speed.

°  Hook &. line - number of trips, hours  per trip and  number
   of lines fished
Estimates of Biological Statistics
Individual organisms  in the biological  sample are  weighed
and  measured.    In cases where accurate  length/weight
relationships are  established,  only lengths  may be  taken.
If required, subsamples are taken to determine  sex,  collect
hard parts (scales, otoliths,  fin rays,  etc.)  for laboratory
age determination and to collect gonads to  develop  maturity
and  fecundity   schedules.    All  sample  sizes must  be
sufficient  to   allow  accurate  characterization   of the
harvests.

Biological statistics must also be coupled with the  type  of
gear used for harvest in order to determine the selectivity
of the gear  and  the representativeness of the  sample.   This
can be achieved  either by taking samples at fish  processing
points which can be associated with gear by interview,  or  by
                      38

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sampling  directly  on board  commercial  boats.   The  latter
will eliminate the uncertainty that may occur with  dockside
samples,  and  also  will  provide useful information  on  catch
per unit effort (CPUE).
                 Techniques  for Estimation
           of Commercial Catch,  Effort,  and  Value

A  myriad  of possible methods exist  for estimation of
fisheries  statistics.   The  following descriptions  of  many
possible  alternatives  is not  all  inclusive.   All  of the
methods  described are  in use  or have been  used  in the
Chesapeake region.

Comparative Adjustment
Another cost  efficient  method,  apparently  still in use for
some  fisheries  in some areas,  is  for  statistics  agents to
visit a  selection of fish dealers  for  information  (usually
verbal)   on the  relative  magnitude of  recent  catches.   A
factor  is calculated  to adjust  previous figures.   For
example,  if  a consensus  is  developed  that  the harvest of
species X  is  down 10% from  the  previous  year,  last year's
figures are decreased 10% to  calculate this  year's harvest.

Advantages are  in the  area  of cost  and  unobtrusiveness.
Disadvantages are inaccuracy, imprecision, no disaggregation
of estimates, no effort data.

Dealer Censuses
This  is  one of  the most  common methods of collecting
fisheries  statistics throughout the  world.    Periodically
each  licensed fish  buyer is  visited.    The  agent either
reviews the buyer's  records  or  obtains  a  verbal or written
report  on recent  activities.    Advantages  of  this system
include: relative unobtrusiveness;  relatively low cost;  when
no basket trade is involved,  landings and value data can be
quite good;  it  maintains a  direct agency  contact  with the
industry.   Disadvantages  include:   lack of fishing effort
data;  underestimates  of  landings  when   dealers  don't
cooperate or in fisheries with large   basket  trades;
disaggregated data is  more  difficult to  obtain than  in a
system dependent on harvester reporting; daily  estimates of
catch are not usually available.

Harvester Censuses
In this type of system, each licensed harvester is  required
to send  in a report on  some periodic basis.   Advantages
include: complete coverage of  all  licensed  fisheries,   i.e.
basket  trade should be  included in  harvest estimates;
disaggregation of estimates  can  be accomplished  on the
reporting form;  effort data can be  reported directly by the
harvester.   Disadvantages  include:  this type of  system is
                      39

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very intrusive and quite  costly; recall and truthfulness are
questionable if there  is  no cross-checking audit system; due
to  late submission  of  reports,  the  system  will not  be
timely;  any  failure  to  complete  the  census  means  an
automatic under-estimate  of  catch;  separate  systems  would
usually have to be constructed  for dockside value data.

Harvester Sample Surveys
In  this type  of  /system, only a sample  of  fishermen  are
periodically required to report their catch.   From  the
sample, an average catch  per  license is calculated and this
figure multiplied by  total number of  licenses  to estimate
total  catch.   Advantages  include:  lower  cost and  less
intrusiveness than with  a census;  defined  allowable  error
ranges  can  be designed  into  the system;  non-reporting  is
less of a problem than  in a  census system;  basket  trade
should  be  included in  harvest estimates;  effort data  is
obtainable directly  from the  harvester  reports.    Disad-
vantages include: disaggregation  requires  wider confidence
limits or larger  sample  sizes;  recall  and truthfulness can
be questionable.

Trip (Transaction) Ticket Censuses
This  type of system  requires  that  each  day's  fishing
activity is  recorded  on  a transaction ticket,  with  a copy
sent to  the  management  agency.   The  system  can  depend  on
either the dealers or the harvesters to  be responsible for
submission of the ticket.  If dealers are to be responsible
then a requirement needs to  included  for harvesters  to
report when  their catch  is not sold to  a  licensed dealer.
Advantages of  this type  of system  include:  every required
level of detail can be included; catch, effort and value can
all  be collected  in  one  system;   completion  of  the  trip
ticket  should become  routine  and  copies  can be  used  for
records purposes for both harvesters and dealers; recall is
not  a  concern.    Disadvantages  include;  the system  is
relatively intrusive;  agency  cost is relatively  high;  the
system  cannot be as  timely  as  may be  required  for  some
fisheries.
  A Framework for Commercial  Fishery Statistics Collection

The preceding  section detailed  the  data  requirements and
techniques for collection of  data from commercial fisheries.
Current   programs  use   these   techniques,  but   in  an
inconsistent manner.   A satisfactory,   baywide  statistics
program is  essential  for stock  assessment.   The following
description  is  a proposal    for developing  an  integrated
program.   Over  the next year,  this  proposal  should be
critically reviewed  for feasibility of implementation.

The foundation  of the proposal  is a  mandatory  commercial
                      40

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harvest  reporting  program.   A transaction ticket  system is
the  suggested  method of censusing commercial  fishermen  and
dealers.   This method  allows  collection of  information on
catch,  effort,  and dockside value  at  a high  resolution of
time  and area.   Because of data  processing  backlogs,  the
reporting  system may  need  to be  supplemented by  informal
dealer surveys to determine estimates of catch during  short
season,  intense  fisheries (striped bass,  shad,  black drum).
It is  also  likely' that effort information from the  harvest
reporting forms will need to be verified by field  surveys of
effort.  Finally, catch estimates must be partitioned by age
(size),  and  sex  for stock assessment,  which will  require a
comprehensive  biological  statistics  program.     A more
detailed accounting of these programs follow.

Trip Ticket System
Figure  3 shows  a  draft  of  a trip  ticket  which would  be
completed by each  fisherman at  the end  of  a  fishing  day.
Such tickets would be  provided to each  fisherman  in  a three
part  receipt  book  format  similar  to  those  used  in  res-
taurants and  other  cash businesses.    One  copy would go to
the  management  agency,  one to  the buyer  and one  to  the
fisherman.   Copies  would be sent by the  licensed fishermen
to the management agency weekly.

Figures  4  and 5 show  samples  of the  coding  systems  which
would be provided with  each booklet of  trip  tickets.   These
would  be printed on the inside  and  outside covers  of  the
booklet.

Careful  record keeping  would  be necessary  to insure  that
every  person was  sending in  reports  in  a  timely  manner.
Penalties must be assessed for those individuals  who  do  not
comply.  Fishermen  must  have  an  incentive  for compliance;
that  is, they must be  shown  that  it  is  in  their  self
interest to provide the information.

A drawback  to this  system  is that  no census  can ever  be
complete; some fishermen will not comply,  some paper will be
lost, etc.   One  possible way around this would be  to treat
the entire trip ticket census as  a large "sample"  and expand
up to the total  license  count.  The effects  and validity of
this idea should be studied using existing data.

A transaction  ticket system would generate large  amounts of
paper.  The only way to tabulate  large amounts of  paper in a
timely way  is through  automation.   Computer  machinery  now
exists  which  is capable of  reading  human  hand printed
figures with low error  rates.  Such machinery  may well be a
cost effective alternative to key punching of data.

Randomized Dealer Telephone  Survey
For  those fisheries in  which timeliness  is  a  paramount
                      41

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concern and  in  which a  constant  or known  fraction  of the
catch is sold to dealers,  rough  estimates of total catch can
be  estimated  with a  daily or  weekly  telephone  survey of
seafood buyers.   Once good mathematical  relationships are
established between  this  system and the  harvest reporting
system,  it  could  be  used  to  manage   quota  regulated
fisheries.

Surveys for Cross Checking Effort  Data
For some fisheries, a system of vessel  or  net counts would
provide a  good  cross-check on  participation  levels.   Such
fisheries  would be  those in  which vessels  and  gear are
easily distinguishable.

Biological Data for Commercial  Fisheries
Collection of biological data  from commercial harvests is a
critical element  of the  fishery  dependent programs.   The
intercept  point for biological sampling  can either  be on
board  commercial  boats  or  at   dockside.   For  the latter,
landing sites are regularly visited  and  fish measured  either
as they come off the boats or after  they have  been sold to a
dealer. For species in which length-at-age  and length-weight
relationships have  been  established,  length  frequency data
would  be  sufficient,  thus  fish  would  not  have  to  be
purchased.    Purchase  of some fish  is  probably  unavoidable
since they would  have to be dissected for  sex determination
or  other  types of  tissue samples. Recommendations for
biological sampling techniques  for commercial  pound nets has
been prepared by Chittenden (VIMS) under funding by CBSAC.

For sampling on commercial boats,  CPUE data,  in  addition to
the  data  described above are,   collected  with  little
uncertainty as  to origin, gear type, and  level of effort.
Recommendations for this type of program have been prepared
by  Rothschild  (CBL)  for commercial blue  crab fisheries in
the Bay.
                      42

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            FIGURE  3.   SAMPLE PISH TICKET
                DAILY SEAFOOD CATCH TICKET
       000001
 l.a. FISHERMAN'S LICENSE  NUMBER/
  b. CAPTAIN'S LICENSE NUMBER (if
     different)
 2. DATE
                                     month
day
 3. GEAR TYPE USED (see front cover for codes)



 4. TOTAL NUMBER OF PERSONS FISHING ON BOAT
5. a. AMOUNT OF GEAR  (see front
      cover for units)
   b. use as necessary and as
      directed on  front cover
6. MESH SIZE (if appropriate)



7. HOURS FISHED TODAY
8. HpURS SINCE GEAR LAST FISHED
   (if gear  left set in water)


9. HARVEST AREA (see front flap for codes)
10. COUNTY LANDED
                                                       year
11. CATCH  INFORMATION (see bacX flap for species unit  codes)
12.  FISHERMAN'S SIGNATURE
13.  BVYER LICENSE NUMBER
    (if appropriate)
                                                    LLJ
a. PRIMARY SPECIES SOUGHT
b. CATCH AND PRICE
SPECIES CODE | AMOUNT


1

1
















|

1

1

I






















UNT









1

TOTAL PRICE







D
— 8 —











(
1


<






<



<



|

I

I
                    43

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FIGURE 4.   SAMPLE GEAR AND  AREA CODING SCHEME FOR
              FISH  TICKET BOOKLETS
 GEAR CODES

 FINFISH
 425 GILL NET, 'ANCHOR
 470 GILL NET, DRIFT
 480 GILL NET, STAKE
 275 POUND NET,  FINFISH
 020 HAUL SEINE
 310 FYKE NET
 345 FISH POTS
 210 OTTER TRAWL
 125 PURSE SEINE

 CRABS
 330 CRAB POTS
 680 TROTLINZS
 770 SCRAPES
 280 POUND NET,  CRAB
 390 BANK TRAP
 XXX COLLAPSIBLE TRAP
 703 DIP NETS
 805 DREDGE

 OYSTERS
 840 HAND TONG
 841 PATENT TONG
 943 DIVING
 815 DREDGE

 CLAMS
 803 DREDGE
 855 RAKE
      AMOUNT OF GEAR UNITS
         a.                b.
NET LENGTH  (YARDS)
NET LENGTH  (YARDS)
NET LENGTH  (YARDS)
NUMBER OF NETS
NET LENGTH  (YARDS)
NUMBER OF NETS
NUMBER OF POTS
WIDTH OF MOUTH
OF POTS
OF LIKE
OF SCRAPES
OF NETS
OF NETS
OF TRAPS
OF NETS
OF DREDGES
             NET DEPTH (YARDS)
             NET DEPTH (YARDS)
             NET DEPTH (YARDS)
             LENGTH OF LEAD
             NUMBER OF HAULS
             leave blank
             leave blank
             LENGTH OF TOW (HOURS)
NUMBER
LENGTH
NUMBER
NUMBER
NUMBER
NUMBER
NUMBER
NUMBER
leave blank
NUMBER OF BAITS
LENGTH OF LEAD
LENGTH OF LEAD
leave blank
leave blank
NUMBER OF TONGS
NUMBER OF TONGS
             leave blank
             leave blank
NUMBER OF DREDGES
NUMBER OF DREDGES
NUMBER OF RAKES
                  HARVEST AREAS

 412 ASSAWOMAN BAY
 012 ATLANTIC OCEAN
 005 BIG ANNEKESSEX RIVER
 537 BROAD.CREEK
 013 CHES. BAY - N. OF WORTON PT.
 025 CHES. BAY - N. OF BRIDGE £
                S. OR WORTON PT.
262 NANTICOKE RIVER - ABOVE XXXXX
continued
                          44

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FIGURE  5.   SAMPLE  SPECIES  CODING  SCHEME FOR FISH
              TICKET  BOOKLET
         FINFISH
         0010 ALEWIVES
         0230 BLUEFISH
SPECIES  CODES

        5170 YELLOW PERCH
                                   5290 UNCLASSIFIED BAIT FISH
                                   CRABS
                                   7000 BLUE CRABS, HARD
                                   7028 BLOB CRABS, SOFT
                                   7029 BLUE CRABS, PEELER
                                   7100 RED CRABS
                                   7110 JONAH CRABS
                                   CLAMS
                                   7480 HARD CLAMS, PUBLIC
                                   7510 HARD CLAMS, PRIVATE
                                   7540 OCEAN QUAHOG
                                   7630 SOFT CLAMS
                                   7690 SURF CLAMS
                                   CONCHES
                                   7750 CONCHES

                                   OYSTERS
                                  OTHER SHELLFISH
                                  8081 TERRAPIN
        4180  STRIPED BASS
                                    UNITS

                                    P POUNDS
                                    B BUSHELS
                                    D DOZEN
                                    E EACH
                         45

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              Recreational Fishery Statistics

Fisheries  in  Chesapeake Bay  also  have  a  very  active
recreational  component.   The  effort,  landings and economic
value have been reported for the commercial sector for many
years.  However,  until 1979, with  the  advent of the National
Marine  Fisheries  Service  Marine  Recreational  Fishery
Statistics Survey  (MRFSS), there  was  little data collected
from marine recreational  fisheries.   MRFSS was established
to meet the goals  of  the Magnuson Fishery Conservation and
Management Act of  1976,  which required  management  of both
the commercial and recreational  components of  fisheries
within the 3-200  mile coastal zone.   Prior  to  this there
were  few and  mostly localized surveys  of the recreational
fisheries in  Chesapeake Bay.

Management  of the combined  recreational and  commercial
fisheries of  Chesapeake Bay will  rely on  accurate estimates
of fishing pressure, catch, and biological parameters, such
as size-fecundity schedules and age and  growth.   Since,  in
some fisheries the recreational  harvest is thought to equal
or exceed the commercial catch, reliable  estimates of effort
and harvest  are  of utmost importance  for management  of
Baywide  fisheries.    Equally  important  for  the  equitable
allocation of increasingly scarce  resources  is the knowledge
of  the  size  and  economic  importance  of  the  angling
community.

The recreational  fisheries of Chesapeake Bay target species
which are seasonal or  year round residents in  the Bay  (spot,
white perch,  and  flounder for  example)  and species that have
extensive coastal migration and are resident  in  the Bay as
adults  for  brief  periods only  (river herring,   shad,  and
black drum for example) .   The  type  of  statistical survey
sampling used to obtain information on catch and biological
parameters can be quite  different  for these two  types  of
target species.  The first type can be assessed with a broad
temporal and  geographical design,  while the second type may
require surveys specifically designed for short and intense
fisheries.

Several  methods  exist  for assessing  recreational  fishing
effort and harvest.  Effort can be estimated  from telephone
or mail surveys,  or from contact interviews.  The advantage
of obtaining effort  information from  telephone  or mail
surveys is the reasonable cost  of such  surveys.   They are
most efficient when a recreational fishing license list is
available to  define the sampling frame for the study.  Such
lists exist,   of  course,  only in  states  that have mandated
licenses.   The  disadvantage  of  this method  is  that  the
accuracy of  the  data  is  dependent on the  anglers' memory
recall, which  declines substantially within  months  of the
latest fishing trip.
                      46

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Effort can also be  measured  through aerial  surveys or  from
direct contact angler surveys.   Aerial  surveys are a cost-
efficient method for collecting effort estimates.   They  work
best for fisheries which can  be discerned  readily  from other
recreational usage.   Direct  contact  angler surveys  can
provide  information on  both  effort  and  catch.   Their
advantage is the  accuracy  of information  that is  obtained.
Their disadvantage  is  relatively high cost and.  Catch and
biological data  are- also  obtained through  contact angler
surveys,  where  agents  can actually  identify,  measure,  and
weigh the  fish.   Contact  surveys are  used  in conjunction
with telephone  mail questionnaires  and  aerial  surveys to
provide accurate catch  data.

The  most extensive survey  currently  being   conducted in
Chesapeake Bay  is the  MRFSS.   It  is a dual-frame survey.
Effort  is  expanded  from  information  obtained  through
telephone interviews of coastal  residents.    The  ratio of
fishing  households  to   the  total  of  households  called is
used, in combination with U.S.  Census data  to estimate the
total number of fishing trips.   Access intercept interviews,
where anglers  are contacted  at  fishing access points,  are
used to estimate fishing success rate,  catch and biological
parameters.   Additionally,  the  intercept interviews  serve to
determine the  effort for angling parties who  live outside
the  regional  coastal   area  addressed  through  telephone
interviews.

Although the MRFSS is based on  sound statistical design, the
intent of the  survey is to  give estimates  of recreational
harvest and  effort  for  broad  geographic areas.    For  the
purposes of  stock assessment  and fisheries management in the
Bay  it may  be  necessary to  have better refined estimates.
In  1989,  CBSAC will  fund a  study which will detail  the
sampling  requirements  necessary to provide  satisfactory
recreational  fishing statistics  for stock assessment.   The
adequacy of the MRFSS and  other survey  designs for meeting
the requirements will be explored.
                      47

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            FISHERY  INDEPENDENT DATA COLLECTION

Fishery independent  monitoring is the  collection of  data  on
abundance,  distribution,  and biological  characteristics  of
fisheries stocks through the use of  statistically  designed
survey methods.   The surveys are  intended to complement  and
supplement   information  produced  by  fishery  dependent
monitoring of commercial  and recreational fisheries.   Thus,
the  term   'independent'  refers  to the fact that data
collection  is  not  dependent  on harvests as  a  source  of
biological statistics.    The primary objectives of  baywide
fishery independent  surveys  are as follows:

0  Collect data  necessary to derive estimates of relative or
   absolute,  age-specific  abundance  for  the tributaries  and
   mainstem bay.  Highest priority life  stages will likely
   be pre-recruits (juveniles) and adult spawners.

°  Collect  other  data  useful   in  stock  assessments  to
   determine age specific patterns  of distribution,  growth,
   mortality, fecundity, sex and maturity.

Current methods for  fishery independent  sampling of marine
organisms  have ranged from the  conventional,  eg.  beach
seines   for   striped   bass   juvenile   fish,    to   the
unconventional,  air conditioner  filters for blue crab
megalopae.   A review of current  methods  can be found in  the
Chesapeake Bay  Program Biological Monitoring Atlas.   A  few
of the more common methods are found in Table 1.

It  is  not within the  scope of  this plan to specify  all
aspects of survey designs that are required  to provide  the
fishery   independent  information   necessary  for  stock
assessment.   Nor is  it  likely  that  it could  be  done.
Uncoordinated surveys employing many if not all of the gears
listed   in   Table   1  are   undertaken   in  the   various
jurisdictions of  the Bay  every  year.   Some are long term
programs, others  are  shorter  term  experimental  projects.
However,  all have advantages and disadvantages.  The task of
evaluating   these programs is  not  simple  and  requires
thorough  analysis to  determine  which  programs  should  be
further  developed  for  assessment purposes.    This  process
should   occur   during   the   course  of   individual  stock
assessments.  However,  it is  possible,  and it will  be  the
purpose of this section,  to  review the primary alternatives
for  development  of a baywide  core  program for  fishery
independent data collection.

In  1985, CBSAC  began  the  process  of  reviewing existing
programs by funding  projects concerning the juvenile finfish
trawl program in  Virginia and the beach  seine surveys used
in Maryland, Virginia,  and the District of Columbia.
                      48

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Table 1.  Representative gears for fishery independent
            sampling.
LIFE STAGE
  GEAR OR METHOD
USED FOR ENUMERATION
Meroplankton (eggs & larvae)
  lined trawls
  plankton nets
  pumps/filters
Juveniles

fish/crabs


shellfish
  trawls (lined/unlined)
  beach seines

   substrate  samplers
  'spat' collectors
Adults

fish/crabs

shellfish
  trawls, gillnets, and
  other commercial gears
  scrapes
  dredges
  bottom grabs
Beach  seine  surveys are  an integral part  of striped  bass
research and management  in  Virginia,  Maryland,  and  the
District of Columbia and from that respect will continue for
the foreseeable future.   Due to the  recent  investigation of
the survey,  methodologies  in  all  three  jurisdictions  have
been standardized.

Deliberations on a trawl  program for the  Bay  continue.   The
committee sponsored baywide trawl  projects in 1988;  it plans
to  hold  a workshop  in Fall  of  1988  to  complete  a  final
design for a  baywide trawl program.   It is  the  collective
decision of the  committee that a unified,  consistent trawl
program  should be one of  the  primary monitoring tools  for
finfish and crab stock assessment.

The following  outlines describe the recommended  approaches
to  fishery  independent monitoring  of  finfish,  crabs,  and
shellfish.
                      49

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  Finfish Monitoring -  trawl,  beach  seine, and other gears


The Bay Trawl Study

Objectives:

°  Collect information necessary to  derive estimates of
   abundance for juvenile  and/or  adult  fish and crustaceans.

0  Spacial and  temporal coverage of the  survey  will allow
   documentation of habitat utilization by the  species
   sampled.  Samples will  be taken in all major tributaries
   up to tidal freshwater,  and in the main bay.

°  Survey will  provide biological samples  for life history
   studies and other concurrent scientific investigations.

0  Survey will be coordinated  among  jurisdictions to provide
   long term, consistent estimates of abundance for the bay
   and its tributaries.

Sampling Design:   Stratified, randomized  block design,  bay
area will  be broken into  large  geographic segments roughly
based on salinity and habitat characteristics.  Within  each
segment, random sampling will  be  stratified by depth.

Gear:  Gear  configuration is undecided.  Current tests  have
involved a 30'  trawl and  larger vessels  (>40').   Smaller
trawls may also be  needed  to  work in the upper tributaries
and shallow  water areas.   Gear will be selected within one
year and will be consistent among jurisdictions in sampling
areas with similar characteristics.

Temporal Resolution:  Sampling will  occur at least monthly.
As the  survey develops  sampling  frequency may be  increased
or decreased,  dependent  on abundance,  during certain  time
segments to  improve the  precision of  estimates  and  the
efficiency of the survey.

Spatial  Resolution:   In Virginia plans are  being made to
develop the survey  initially  in  the  tributaries  with
expansion to the main bay.   Depth ranges under consideration
are:  3'-12'  unsampled unless by smaller trawl;   12'-30',
30'-42', >42'sampled by large  trawls.   In  Maryland  a similar
strategy is  being developed.  The District of Columbia  will
use a smaller trawl.

Species:   Weakfish, striped  bass,  croaker,  spot, spotted
hake,  white perch,  silver  perch,   anchovy,   hogchoker,
menhaden,  eel,  channel  catfish, white  catfish,   toadfish,
silversides, alewife, blueback herring,  blue  crab
                      50

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Implementation:   Maryland has  proposed a  five year  trawl
project at CBL through W/B funds.   Virginia plans to upgrade
the  VIMS  juvenile  trawl  survey  through  additional  state
funding that  was  approved in  the  1988  General  Assembly.
Both projects  will  be in  a  developmental  phase  into  1989.
CBSAC  proposes to hold  a technical  workshop beginning  in
Fall of 1988 to aid in the development of the survey design.
Beach Seine Survey

Objectives:

°  Collect data to  derive  estimates of abundance  for  young
   of the year striped bass, and secondarily  for  other fish
   using the near shore zone.

0  Document habitat utilization  of  striped bass,  and  other
   species, in the important striped bass  nursery areas.

0  Collect biological samples for life history studies.

0  Maintain a long term, consistent,  cooperative  survey  for
   striped bass assessment and management.

Sampling Design:   Systematic  sampling - fixed  stations  and
times

Gear:  100' x 4' beach seine,  1/4 inch mesh

Temporal Resolution:  Samples are taken approximately once a
month from July through September (2 seine hauls per station)

Spatial Resolution:   22 stations in  Maryland in  the  upper
bay, Choptank,  Nanticoke,  and  Potomac Rivers.   18 stations
in Virginia in the James, York, and Rappahannock  Rivers.   5
stations in the District  of Columbia in the  Potomac River.
Stations  are limited to  favorable  seining sites in  the
nearshore zone (0-3').

Species:   Striped bass,  white perch.    Other  species  are
captured;   Virginia's survey has recorded  over  50 different
species.  All are not representatively sampled.

Implementation:   Beach seine surveys will  continue as in  the
past.   Review of the  survey  and the  associated  historical
data base  will occur  during  the  course  of  baywide  stock
assessment  of  striped  bass.   Additional  work should
be funded to investigate the utility of the survey for other
species.
                      51

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Other Fishery Independent Finfish Surveys

Objectives:   The  objectives  of  other types  of  fishery
independent surveys would be  the  same as those  listed for
the trawl and beach seine surveys.  The primary objective of
alternate  surveys  is  to collect  information  on  finfish
species or life stages not  obtained from the trawl or beach
seine surveys, or from fishery dependent programs.

Sampling Design:   Will  be  dependent  on specific objectives
of the  survey.   Statistical  properties  of  proposed surveys
to be considered during planning.

Gear:  Commercial gears employed with a statistical design -
gillnets,  pound nets,  fyke nets,  trawls.    Specialized
sampling  devices  -   designed   traps,   electrofishing,
hydroacoustics,  pop nets.

Temporal/Spacial   Resolution:      Dependent   on   survey
objectives.

Species:   Dependent on perceived  needs  for  management and
assessment.

Implementation:   Of immediate concern,  is the establishment
of a consistent survey for juvenile shad and herrings.   The
gear  of choice  appears to  be  a  boat  mounted  push  net.
However, sampling  difficulties and funding  have  thwarted a
consistent survey.   It is  recommended that  a survey be
instituted in  Maryland, Virginia,   and the  District  of
Columbia.
               Shellfish and Crab Monitoring

Blue Crab

Objectives:

°  Collect post  larval  and  juvenile  blue  crab data  as an
   index of potential recruitment.

0  Survey yearling and adult crabs as an index of abundance
   and distribution.

0  Document and quantify habitat use  (non-vegetated and SAV
   beds) by life stages.

Sampling Design:   Post larval stages  can  be collected and
abundance  quantified in  planktonic  samples  near  the  Bay
mouth and in marsh areas on megalopae collectors.  Juveniles
and  adults  are taken by  finfish  trawls.  Shallow  SAV  beds
require specialized sampling.
                      52

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Gear:  Plankton nets, "megalopae screens", otter trawl,  SAV
push or pop nets.

Temporal Resolution:  Planktonic collections should be  made
weekly  during  the  "spawning"  season; megalopae  can be
collected daily during  a  10-day period bracketing the  full
moon; and  juveniles and  adults should  be enumerated  from
finfish trawling surveys on a monthly basis.

Spatial Resolution:  Plankton collections can be made along
a transect across the Bay mouth.  Stations should be  spaced
to include inflow and outflow waters.   Megalopae collectors
should be  placed  in representative  marsh  sites.   Juvenile
and  adult  samples  are  collected  from  the  stratified,
randomized finfish trawling.

Species:  Blue crab

Implementation:  Maryland  and Virginia must continue their
commitment to  the  trawl surveys.  Other juvenile  sampling,
whether planktonic  or post settlement,  should be  evaluated
as a part of  a long  term  monitoring  program.    If these
additional programs are appropriate  they should become  part
of the core monitoring programs.

Oysters

Objectives:

0  Collect data  on  annual initial  (summer)  and  surviving
   (fall) spatfall on public oyster  bars to derive an index
   of recruitment.

°  Survey  spring  and  fall abundance  of  seed,  small,   and
   market  oyster,  and   predators   (drills,   mud  crab,
   flatworm)  and fouling organisms  on public  oyster bars.

°  Survey incidence of MSX and Dermo on selected public  bars
   to maintain an index of infestation.

0  Measure condition index  (CI)  of oyster on selected  bars
   as an index of health and spawning condition.

Sample Design:  Systematic sampling of public oyster  bars in
the mainstem Bay and tributaries.  Repetitive samples  should
be collected.

Gear:  Hand tongs,  patent tongs, dredge.

Temporal  Resolution:    Spatfall data  should  be  collected
weekly from  June through  September;  fall and spring  survey
counts need only be sampled twice a  year;  disease  incidence
                      53

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should be monitored  weekly throughout the active infestation
periods;   and  CI  needs   to  be  measured  monthly   at
representative stations.
Spatial Resolution:  Public  oyster bars

Species:   oyster, MSX, Dermo,  tunicates,  bryozoans,  oyster
drill, pea crabs.

Implementation:  Maryland and  Virginia  have monitoring
programs for  spatfall  and  disease.   Methodology  should  be
standardized and  augmented  as indicated by  the  objectives,
All  oyster monitoring programs need  to  be infused with
additional funds.
Clams (hard and soft)

Objectives:    Establish  an  annual  survey  of  clams  to
determine recruitment,  abundance, distribution, and growth.

Sample  Design:    Stratified  by  depth,  substrate,   and
salinity, and randomized sampling  on  known or historic  clam
beds.

Gear:  Patent tong,  dredge and hydraulic escalator dredge.

Temporal Resolution:   Twice-annual sampling,  weekly during
periods of recruitment.

Spatial  Resolution:   Baywide

Species:  Hard clam, soft clam

Implementation:   Neither  Maryland  nor  Virginia have a
monitoring program  to survey stocks  of  juvenile  or  adult
clams, nor are  any  programs  under  development  to obtain an
index of recruitment.   Because of the  economic importance of
clams, these programs should be  initiated.
                      54

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                RECRUITMENT PROCESS  STUDIES

The  process  of adding members to the  exploitable stock is
termed the recruitment process.   It  covers the period in the
life history beginning  at  the egg stage and  ending at the
onset  of  fishing  mortality.    In terms  of   population
dynamics, the period encompassing the recruitment  process is
usually  characterized by  high   mortality  rates  and  large
year to year  fluctuations  in  abundance.   Environmental
variables, natural and man induced,  play the most important
role in  governing  survival  during  these  life  stages.
Although predation,  competition,  cannabolism,  and  spawning
stock conditions will  also influence survival  to a greater
or  lesser  degree in  some  species.    As  such,  recruitment
process research usually serves as the basis for determining
critical habitat requirements.

Generally, the  effect  of  factors that  determine the degree
of contribution of a  given year's spawn to the exploitable
stock (termed  yearclass strength) occurs  in  the first year
of life. These factors  may be related  to  the  abundance of
spawners that  produced the  yearclass  or the  abundance of
members  of the yearclass themselves  (density  dependent
factors),  or  related  to  biological  and  habitat  events
unrelated  to  their  abundance or the  abundance of  their
parents  (density  independent  factors).   The objective   of
recruitment process  studies  is   to  examine  the  extent   to
which density  dependent  and density  independent  factors
influence the establishment of yearclass strength.  As such
this type  of  research  in  part  will  seek to  quantify the
effects of environment on resource production.
                          Approach

It is necessary to determine the pattern of survival during
the period  of  the recruitment process, and  to  relate this
pattern to  trends in  biotic and  abiotic  variables.   The
relationship can  be inferred  from analysis  of  stock  and
environmental monitoring  data,  or  can be  tested directly
through   controlled  laboratory  and   field   studies.
Recruitment process research yields best results when it is
a combination of the  two.   Inferences drawn from analysis of
historical data sets  can be used to formulate hypotheses for
laboratory and field  testing.

Given the  adequacy of available data sets, it is possible to
determine  the  potential   influence of  biotic   and  abiotic
factors  on  the  recruitment  process by   examining  the
historical   relationships  between  stock   size,  fishing
mortality,  environmental  variables, pollutant loadings,  and
habitat loss.   This type  of analysis, termed  time series
analysis,  requires a  series of continuous measurements over
                      55

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a considerable length of time, since stock abundance varies
on annual cycles.   Missing data,  imperfect  sampling, spatial
incongruities in  measurements,  and  data sets  with too  few
observations are  several  of  the major factors that inhibit
time series analysis.  Some of these inhibiting factors  may
be  overcome  by  data  interpolation,  use  of  alternative
(proxy) data sets, and adjustment of the  level  of  resolution
to a broader  scale.   An  example of  such an exercise,  which
involves the  white perch  populations  in  the  Choptank  and
York  rivers,  has  been documented  by the  CBSAC  Data  Set
Identification and Interpretation Working Group (see Related
Readings).

                         Data Needs

While  retrospective  analyses  furnish important information
for  understanding the factors  that  are important  in  the
recruitment process,  they should not hinder efforts to move
forward  with  the  collection  of  new,  better  suited  data.
There  often exists  a tendency to  conduct retrospective
analyses first,  then  design a sampling program  to  accomplish
what could  not be accomplished  using historical data sets,
leading to further and further delays in  getting on with  the
task.   Based on  the  retrospective analyses  performed  to
date, scientists  have gained a appreciation for the types of
data  sets  that   would be  most  useful,  given  available
methodologies and techniques for time series analysis. These
generic criteria  are  summarized  as follows:

0  Observations  should be  taken often  enough to include
   short term (seasonal)  variability.

0  Enough  locations  should  be  sampled to  cover spatial
   variability.

°  A long enough time series is necessary to show  potential
   long term changes  or trends.

0  Observations  need  to be taken in a consistent manner. The
   same techniques and gear should  be  used  throughout  the
   time series.

0  The observations must  be on a variable that  is  related in
   a consistent  manner to the parameter being estimated.

0  Choice of  environmental variables to measure  must make
   good biological sense.

Usually one or more  of these general criteria  are not met.
Sampling programs focused on early life  stages  are typically
limited  to  certain habitat  types  (e.g.,  beach  seines  are
limited to  beaches),  have sampling  frequencies that exceed
life  stage  durations,   and do  not  coincide  well  with
                      56

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environmental monitoring  programs  in terms  or  spatial and
temporal resolution. These limitations result in failure to
detect   causative   relationships   with  any   degree  of
statistical confidence.  With these problems in mind,  it is
recommended that CBSAC continue to work with the Monitoring
Subcommittee of  the Chesapeake  Bay Program to ensure  that,
where possible  monitoring data  sets include environmental
variables  important to assessment  and are  established on
temporal and spatial .resolutions compatible with  assessment.
Furthermore, where  possible,  programs designed  to  collect
data  related  to  stock  parameters  (abundance,   growth,
distribution, and  mortality)  should  also  collect   relevant
environmental data.

Basic  data  needs  relative to  the  study of recruitment
processes include life stage specific estimates of  abundance
and development  (growth)  rates.   To  approximate the  pattern
of  survival  through the  life  stages  involved  in the
recruitment  process,  age specific  estimates for  daily or
weekly  cohorts  within a  life  stage  should  be  determined.
This will allow analysis  of  the  age structure within a  given
life stage  (which may last from one day to several  months),
and will enable comparison of survival  rates to growth
rates.

Age specific estimates within  the early  life  stages will
also  enable  determination of  the  approximate   date  of
spawning and allow  comparison  of the  survivability of the
offspring to the condition  of the  parents.   A  significant
part  of the recruitment  process is  related to the  adult
population  itself.   Such factors as  behavior,  adult  stock
structure (age,  size, and sex ratio),  genetic variability in
egg quality, and fecundity,  influence the  survivorship and
development of  the offspring.

                    Selection of Species

Research on the  recruitment process will involve dedication
of a  significant amount  of  scientific resources  because of
the type of information that needs  to be retrieved.   Initial
research efforts  should  focus  on  species   considered
important   in   fisheries   management.    Commercial  and
recreational finfishes  of  interest  include  striped  bass,
American shad,  river herring,  yellow perch,  white perch,
spot,  croaker,  and seatrout.  Shellfish of interest  include
blue crab and oyster,  for which physical and environmental
factors have  been  suggested  as   the  most  important  in
controlling the recruitment  process.

Second priority should go  to those  species  that appear  to be
a significant factor  in  controlling the  year class  success
of commercial and recreational  species.  These ecologically
valuable species  include  potential predators,  competitors,
                      57

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and prey,  as well  as  plant  species  that are  significant
components of critical habitats.
                       Conclusions

Research on the recruitment process is valuable to fisheries
management in that it  supplies:

°  Information  on  critical  habitat   requirements   for
   important species.

0  Estimates  of potential  strength  of age  classes  that
   will be entering the fishery.

°  Information on the  trend in the abundance of a species as
   it relates to trends in the ecosystem.

0  A basis  for  evaluating habitat condition  and alteration
   of the environment.

°  An  improved understanding of  the relationship  between
   stock size and recruitment.

Approaches to recruitment  research have  been developing
rapidly  over  the last  several  years.   There  are  many
sampling and measurement difficulties inherent  to  the  type
of  work  described.    CBSAC  recommends  that  any  work
undertaken to investigate recruitment dynamics be carefully
planned before implementation.   The  Committee also proposes
to review project results in  the Bay region and key projects
undertaken in other parts of  the world to help better define
appropriate objectives and techniques for future research.
                      58

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                 CHAPTER V.   IMPLEMENTATION
The stock assessment plan is oriented primarily to meet the
needs  of  state  management  bodies  for  information  on  the
status of the fishery resources.  Assessments traditionally
relate status to /the effects of  fishing,  and provide some
basis  for evaluating expected  future  yields and population
changes resulting from  postulated  fishing  levels.    This
usually applies  to  individual  stocks  defined by population
distribution and,  to some  necessary extent,  by practical
fishery management considerations.

It  is apparent  that human development  has resulted  in
significant effects  on  the  resources   supporting  the
fisheries.    These effects  must  now   be  included  in
assessments.   Furthermore, alternative  conservation  and
management practices need to take into account implications
of the multispecies fisheries and ecosystem-related aspects
of natural factors of environment  and species  interactions.

These  additional  considerations  require the  collection  of
more  data,  and  the development  and application  of  new
methodology.   Achieving  this  increased  sophistication  in
assessments  will  take  time,  and requires  that  the first
steps be started  immediately.

Although a rigorous accounting has not been made, there are
at least one hundred persons actively working  on  some aspect
of stock  assessment  in  the  Bay  region.    This  tally would
include fisheries biologists, technical  staff,  academic
faculty,  graduate  research  students and others  working  at
over  twenty  organizations in  the Bay  area.   About three
million dollars  per year are spent on research,  monitoring,
and management programs  that contribute to  stock  assessment.
A  majority  of these costs  are  covered  by  federal  funds
(currently,  approximately  $2.5  million  per year).   An
obvious  challenge  for  development  of  a  baywide  stock
assessment program is the coordination  of  these human  and
monetary resources.

Implementation  will  be   the shared  responsibility  of  the
jurisdictions  whose  fishermen and  other  citizens  benefit
from  utilization  of the resources  and the  Bay, and  the
federal  government.     Implementation  is  obviously  a
cooperative  endeavor; the speed and  effectiveness with which
it is  carried out will  be governed by  factors  outside  the
scope of this plan.   This section only offers advice on the
relative importance, need,  and  mechanisms to achieve  the
objectives of stock  assessment.
                      59

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                     A PROPOSED PROCESS

Figure   6   displays   a   basic  flow   of  organizational
responsibilities and  activities involving fishery  stock
assessment in  the  Bay.   To  an extent,  current assessment
practices follow this pattern, but they must be supplemented
and  better  coordinated to  truly  create an effective
Chesapeake Bay stock assessment process.

A  noticeable  feature  of Figure  6  is  the  division  of
responsibility between research and management organizations
in all jurisdictions.   While there is no single authority by
which stock assessment is controlled, the  formation of CBSAC
in 1985 was intended to  solve  the  coordination problem for
assessment activities.    The  committee  has the appropriate
membership, with the assistance of its work groups,  to solve
technical   stock   assessment  problems   and  it   is   a
recommendation of this plan to continue  the committee with
further  direction  to begin  a  more active  role in  the
oversight  of  fisheries stock  assessment  activities  in the
Bay.

The most  effective  way  to integrate  assessment activities
will be to encourage as much interaction as possible between
representatives from  all jurisdictions  on  technical  stock
assessment problems.   During  the  first  several  years  of
CBSAC this has been  achieved through the  activities  of the
committee's workgroups.  Their responsibilities  have been
to review  and  analyze  data  sets  for the  purpose of  better
understanding   shortcomings in  available  data  in  order  to
improve their  utility  and to  suggest improvements  for data
collection programs.

A stronger role by  the working groups is needed to  implement
the programs proposed herein.   These groups would  serve to
focus and  coordinate  among the large  number of individuals
contributing   to stock  assessment.    In  addition to the
present workgroups,  Status of Stock  Knowledge  (SOSK), Data
Set Identification  &  Interpretation  (I  &  I) ,  and  the Data
Base Coordination  (DEC),  new  workgroups  will  be  initiated
for finfish, oysters  and blue  crab.   For this approach to
succeed,  it is essential that  the  jurisdictions contribute
adequate staff time for preparation of technical documents.
For an interim period,  it may be wise to have each workgroup
have one full  time  staff  person.

The foregoing  discussion generally  describes  some  of the
organizational ideas that will be  useful  to build a stock
assessment process for  the  Chesapeake  Bay.   The  most
important  point  is  the continuation   of  CBSAC  as  a
cooperative means of overseeing stock assessment in the Bay.
                      60

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A revised terms of reference for the  committee  would  be as
follows:

o  Coordination,  review,  and oversight  of  data collection,
   processing,  archiving, and analysis.

o  Preparation of  annual  Fishery  Statistics and  Status of
   Stocks Reports, and  periodic Status of  Stock Knowledge
   Report.

o  Organize working groups  and conduct workshops to complete
   needed analytical  assessments.

o  Recommend research projects to provide information needed
   for assessments.
A  summary  of  the  major  features  of  a  baywide  stock
assessment program and  recommended  dates  of implementation
follows.

                Fishery    Stock  Assessment

Stock  assessments  will  be overseen  by  CBSAC.    Baywide
working groups for  finfish, crabs,  and  oysters will  be
established to coordinate and focus the multitude of stock
assessment scientists.   The present working  groups  (SOSK,
I&I,  DEC) will continue  with  the  respective  tasks  of
reporting on status of Chesapeake Bay stocks, investigating
analytical techniques,  and  coordinating   data  management.
Annual cooperative reports documenting  status of stocks and
fishery  statistics,   and  periodic   reports   detailing
assessments will be  produced.   Assessments should begin as
soon as workgroups are  established by  CBSAC.   Initial work
will  depend  on analysis  of  historical  data.    Special
attention should  be  directed in these  initial  assessments
towards critically  evaluating  all current and  proposed
monitoring programs.

              Commercial  Fishery  Statistics

The jurisdictions will improve existing statistics programs
to build a baywide fishery statistics  program to obtain and
document annual, unbiased estimates  of catch, landings, and
fishing effort.  At  a minimum the estimates  will  be broken
out by species for  each  type  of gear,  for each  month of
catch,  and  for  each water area.    Actual  procedures  for
improved harvest  reporting,  fishing  effort estimation,  and
data management should be  finalized within one  year of the
approval  of this  plan and should  strongly consider  the
framework proposed in Chapter IV  (particularly  a mandatory
commercial tripticket system).
                      62

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              Recreational  Fishery  statistics

Investigate the utility of statistics generated by the NMFS
Marine  Recreational  Fishery Statistics  Survey  (MRFSS)   for
Bay  stock assessment.   Augmentation  of that  survey with
state  and federal funds  may be  all that  is  necessary to
provide unbiased,  annual estimates of recreational catch  and
effort  at a  comparable  resolution  to  commercial  harvest
data.    Review  of   the  MRFSS  survey  and  a  plan   for
recreational  statistics  collection  should  be  completed by
December 1989.

           Biological  Characteristics of Harvest

One  of the poorest  aspects of current stock  assessment
information is the lack  of  knowledge of age composition of
harvests.   Biological  samples  must  be  collected annually
from both recreational and commercial harvests to obtain  the
necessary data on  species composition and age composition.
Improvements  in  age   determination  capabilities  will  be a
necessity for this program.  Virginia plans a pilot program
for  biological  sampling  of commercial  harvests  for July
1988;  funding and staff  have been approved.  Maryland will
also begin a  broader  scale  program  after the initiation of
new harvest reporting procedures.

                  Fishery  Data Management

An emphasis must be  made  on data sharing, particularly  for
time  series   of  routine  harvest/  effort,  and  recruitment
data.   Non-confidential data bases  for each of the routine
data sets  should  be  available  for  stock assessment  within
six months of the  end of each  calendar  year.   Common data
files   should be  maintained  for   harvest,  effort,   and
recruitment data.    Annual   or  biannual  fishery  statistic
reports  should  be used to  document and  disseminate this
information.   Guidelines  that  increase  access  to research
data while protecting the  obvious  rights of  individual
investigators  should  be developed.    All  pertinent data sets
will be properly  documented and  stored  in  a  central data
center.

                Fishery  Independent Surveys

Recommendation is  to  adopt a  long  term, baywide  trawl
program to obtain  fishery independent estimates of abundance
and distribution of many  of  the important fish species  and
crabs.   The cooperative trawl project would be augmented as
necessary by other  sampling  methodologies  to  obtain
abundance estimates for species  and  life  stages not captured
by the trawl.  At least one  important  alternative   method
will be beach seine  surveys for  anadromous fish.   Pilot
projects   for  a   trawl  program  were  begun   in   1988.
                      63

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Implementation of  the program  should  begin by  spring  of
1989.  In addition, analyses of  existing fishery independent
survey data  should be improved.   This will  occur to  some
extent through  the development of  baywide assessment  work
groups, but will also require the addition of staff to  some
state programs (see Table 2).

                Recruitment Process  Studies

A variety  of research projects  to  investigate  recruitment
processes  have  been  undertaken  in  the  Bay region.    Key
species  have been  striped  bass,  oyster,  blue  crab,  spot,
croaker,  and flounder.  A review of  Bay recruitment projects
and  similar  projects worldwide  should  occur  in  order  to
better define research objectives and  sampling  designs  that
would best determine the relative effects of  environment and
fishing.

                  Biological   Monitoring

The  fishery  dependent  and  independent  data  collection
techniques described in Chapter 4 serve as the basis for the
monitoring of fishery species, as well as other  ecologically
important finfish, of the Chesapeake Bay.  Assessments  will
seek to use both long term  monitoring  information  and  short
term  research information  to  understand  the  dynamics  of
these  living resources.    Stock  assessment data  collection
programs will  be  coordinated with  Bay monitoring  programs
for water quality, and benthic and plankton communities.  An
initial medium for reporting these data that will  lead  to a
description of the relationships between the  environment and
fishery  resources  will  be  the  biannual  State  of the  Bay
Report.

                   Funding Considerations

The  following  table gives  a  rough  accounting of  staff and
budget needs to  meet the  recommendations  within the  plan
(Table 2).  Also included in the table are potential funding
sources  for  the various activities.   Notice that  required
funding increases are not great, and that there  are a number
of potential  federal funding sources.   Three  actions  that
would  aid  program development  are  (1) ensure  a  long  term
funding base such  as  the CB8AC NOAA  appropriation,  (2)  give
state  agencies permission to use federally funded FTE's, and
(3)  ensure  adequate state  funding  for facilities, and for
staff  when  federal  funds  are not  available.    It  is
recommended  that  individual jurisdictions develop  thorough
program   requests  through their   normal  administrative
processes.  The program  changes and  additional work required
to  create a  cooperative  stock  assessment  program in  the
time frames indicated will require the addition of the staff
positions shown in Table 2 by July 1989.
                      64

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                      RELATED READINGS
1982.  Chesapeake  Bay  Fisheries   Management      Primer.
       Chesapeake Bay Commission, Annapolis,  MD. 28 pp.

1982.  Report  of Workshop on  Chesapeake     Bay  Fisheries
       Statistics.  CRC Publication 107.  Ill  pp.

1982.  Report of   the Workshop on Blue Crab  Stock  Dynamics
       in Chesapeake Bay.  UM-CEES II ES-01-83. 168 pp.

1983.  Choices  for the Chesapeake:   An  action     agenda.
       Chesapeake Bay Program.  85 pp.

1983.  Implementation of Recommendations on Chesapeake  Bay
       Statistics.  Chesapeake  Bay  Cooperative  Fisheries
       Committee. 21 pp.

1984.  An Action Program to Develop a Management System for
       Chesapeake Bay Fisheries.  UM-CEES (CBL) 84-7.  14 pp.

1985.  Chesapeake Bay Stock Assessment  Committee
       Proceeding No.l.  CBSAC. 53 pp.

1986.  Chesapeake Bay Stock Assessment  Committee
       Proceedings No. 2.  CBSAC. 82 pp.

1986.  An   Evaluation  of   Information   Available   for
       Managing   Chesapeake  Bay  Fisheries:   preliminary
       stock assessments, Volumes I and II.
       UM-CEES (CBL) 85-29. 373 pp.

1987.  Status of Stock Knowledge Bibliography.  CBSAC SOSK
       Working Group.  96 pp.

                      UPCOMING REPORTS

1988.  Status of Chesapeake Bay Fishery  Resources.   CBSAC
       SOSK Working Group.

1988.  Status,  Trends,  Priorities,  and  Data  Needs  for
       Chesapeake  Bay Fisheries.  Baywide Fishery Management
       Work Group.

1988.  Use of Historical Data Sets to Determine  Causes  of
       Variabilty  and Long Term Trends in the Abundance  of
       White Perch  in the York and Choptank Rivers.  CBSAC
       I&I  Working Group.

1988.  Compendium of Stock Assessment Research Reports-FY85.
       CBSAC.
                      66

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