AEPA
Envir.
Agpr
b5804
Research and Developmont
Larval
Distributions
in Southwestern
Lake Erie
Near the Monroe
Power Plant
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
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This document is available to the public through the National Technical Informa-
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EPA-600/3-78-069
July 1978
LARVAL FISH DISTRIBUTIONS IN SOUTHWESTERN
LAKE ERIE NEAR THE MONROE POWER PLANT
By
Richard Allen Cole
Institute of Water Research
and
Department of Fisheries and Wildlife
Michigan State University
East Lansing, Michigan 48824
R804517010
Project Officer
Nelson Thomas
Large Lakes Research Station
Environmental Research Laboratory-Duluth
Grosse lie, Michigan 48138
ENVIRONMENTAL RESEARCH LABORATORY-DULUTH
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
DULUTH, MINNESOTA 55804
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DISCLAIMER
This report has been reviewed by the Michigan District Office, U. S.
Environmental Protection Agency, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and policies of
the U. S. Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
ii
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FOREWORD
Our nation's freshwaters are vital for all animals and plants, yet our
diverse uses of water—for recreation, food, energy, transportation, and
industry—physically and chemically alter lakes, rivers, and streams. Such
alterations threaten terrestrial organisms, as well as those living in water.
The Environmental Research Laboratory in Duluth, Minnesota develops methods,
conducts laboratory and field studies, and extrapolates research findings.
—to determine how physical and chemical pollution affects aquatic
life
—to assess the effects of ecosystems on pollutants
—to predict effects of pollutants on large lakes through use
of models
—to measure bioaccumulation of pollutants in aquatic organisms
that are consumed by other animals, including man
This report provides insight into the entrainment of fish larvae by a
fossil fuel power plant. Studies were conducted as part of a comprehensive
Western Lake Erie larvae study.
Donald I. Mount, Ph.D.
Director
Environmental Research Laboratory
Duluth, Minnesota
iii
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ABSTRACT
This paper presents and discusses studies of larval fish distribution
near a large power plant on western Lake Erie using methods that attempt
to account for the confounding effect of environmental variation on technique
effectiveness. Distributions in the coastal zone were sampled with daytime
and nighttime tows of 1-m plankton nets. Density and mortality were also
sampled in the cooling system of the Monroe Power Plant. It is concluded
that prolarvae were concentrated in specific areas near spawning sites, but
larvae that .reached the lake proper are rapidly dispersed by currents. Al-
though flooded tributaries may act as important concentration points for
certain species, no concentration gradients persisted in the lake proper.
Certain species of larvae seemed to be more vulnerable to entrainment than
others: gizzard shad were more vulnerable than yellow perch, white bass,
rainbow smelt, shiners (Notropis) carp and goldfish.
This, report was submitted in fulfillment of Grant No. R804517010 by
Richard A. Cole, Ph.D., Department of Fisheries and Wildlife and Institute of
Water Research, Michigan State University, East Lansing, Michigan.
iv
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CONTENTS
Foreward ±±±
Abstract .«, iv
Figures vi
Tables vii
Acknowledgments viii
1. Introduction 1
2. Conclusions 4
3. Methods 6
Description of the Study Site .- 6
Sampling 6
Night transects 6
Backwater, beach and offshore distributions 8
Studies of the power-plant cooling system 8
4. Results ...... 9
Overview 9
Ratios of Prolarvae to Postlarvae 9
Bottom Sled Studies 13
Daytime Bottom Tows Versus Nighttime Oblique Tows 13
Distance from the Maumee River and the Closest Shore 13
Capture in the Discharge Canal 28
Mortality 28
5. Discussion 31
Spawning and Nursery Areas 31
Vulnerability to Entrainment 32
Possible interspecific compensatory interaction 34
References 36
Appendix 39
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FIGURES
Number
The location of sampling stations and the cooling system
at the Monroe Power Plant, Southwestern Lake Erie . .
Mean number of larval fish, larval midges and Leptodora
kindtii in relation to distance (km) from the mouth of
the Maumee River. Each recorded point represents the
mean of all observations made at that distance from
the Maumee River during the sampling expedition 17
Mean number of larval fish, larval midges and Leptodora
kindtii in relation to the closest distance (km) from
shore. Each recorded point represents the means of all
observations made at a specified distance from shore during
the sampling expedition 21
vi
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TABLES
Number Page
3
1 Mean Number of Animals/100 m Caught in All Tows Made in
the Canal, Bottom Sleds and Night Tows in the Lake 10
2 Ratios of Prolarval and Post Larval Stages in Different
Sampling Efforts from April to May 1977 12
3
3 Mean Number of Animals/100 m Caught During the Day with a
Bottom-Sled Towed in Protected Inshore Waters (Flooded
Tributary Mouths) Along the Beaches and in Deeper Water
1 to 2 km Offshore. Beach and Inshore Waters were 4 to
6 m Deep 14
3
4 Mean Number of Animals/100 m Caught at Stations Sampled
both with Daytime, Bottom-Sled Tows and Nighttime
Oblique Tows Without a Bottom Sled 15
3
5 Mean Number of Scarce Larvae/100 m Caught Along Transects
E and G Parallel to Shore in Night Tows . 20
3
6 Mean Number of Scarce Larvae/100 m Caught at Different
Distances from Shore in Night Tows "..-... 27
3
7 Mean Number of Animals/100 m Caught in Day and Night
Integrated Tows in the Discharge Canal at the Monroe
Power Plant 29
8 Estimates of Mortality in the Once-Through Cooling System
of the Monroe Power Plant During 1975 (Day time) and
1976 (Nighttime) Sampling Periods 30
A-l Distribution of Larval Fish, Midges and Leptodora kindtii
Along Night-Sampling Transects 39
3
A-2 The capture/100 m of Fish Larvae, Midges and Leptodora
kindtii in Bottom-Sled Tows Inshore, on the Beach and
Offshore in Western Lake Erie 55
vii
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ACKNOWLEDGMENTS
This work could not have been completed without the efforts of John
MacMillan, Dennis Lavis, Norm Van Wagner, James Wojelk, Roger Jones and
Thomas Wallace. I also appreciate the cooperation of the Detroit Edison
Company, the advice of Don Nelson and Nelson Thomas and the edltoral help
of Diana Weigmann.
Vlii
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SECTION 1
INTRODUCTION
Effective coastal-zone planning requires an improved understanding of
important aquatic resources. Fisheries and cooling water are two particularly
important and potentially conflicting uses of the coastal zone. The potential
for massive entrainment of larval fish and fish-food organisms into once-
through cooling systems at steam-electric power plants is widely recognized
(Marcy, 1974), but the quantification of impact has been thwarted by incom-
plete or ambiguous research results. Representative sampling of fish larvae
is a prerequisite for appropriate management decisions. This report presents
the results of research designed to assess distributions of larval fish along
the western shore of Lake Erie by using techniques that improve upon sampling
efforts described by Cole (1976a).
The siting and construction of large power plants is increasingly based
on some assessment of optimal resource management in the region. The use of
western Lake Erie epitomizes the problem of managing an intensively exploited
aquatic resource. As indicated by population trends (Great Lakes Basin Com-
mission, 1975a), the intensity of coastal-zone use could double over the 40-
year operation of a new power plant. Continued regional growth is likely
to be accompanied by increasing conflicts among resource users. Cooling water
requirements could increase by more than ten times the present demand during
the next half century (GLBC, 1975b; Denison and Elder, 1970) and endanger the
fishery resource because of the large number of young fish drawn into cooling-
water intakes.
Appropriate resource management requires the development of fair cost-
benefit assessment before costly mitigation procedures can be expected. The
retail value of Lake Erie commercial fishing has amounted to $15 to $20
million per year (catch data and values per pound are estimated in GLBC,
1975c) and sport value may exceed the commercial value. Comparable values
are also associated with the implementation of cooling alternatives or other
mitigation procedures that would insure protection of the fishery resource.
Therefore, detailed quantification of resource damage to the fishery, if any,
is a prerequisite to any fair settlement.
Quantitative sampling of larval fish in fresh water only recently has
been pursued seriously (Marcy, 1971, 1973, 1976; Cole, 1976a). Past work has
emphasized enumeration of entrained larvae at power plants with some explora-
tory assessment of the actual proportion entrained from the cooling-water
source. Results of preliminary inventigations in the source waters of west-
ern Lake Erie (Cole, 1976) show that larvae occur in very dilute, shifting,
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aggregated concentrations which require intensive, sampling efforts to quan-
tify any differences in relative abundances. Particularly pertinent were
investigations of population density gradients in relation to distance from
shore. In order to maximize the number of samples taken to contrast abun-
dances within the study area, expediency was served by daytime sampling with
short (less than 5 minutes) oblique tows of uncomplicated gear (1-m, 573-y
plankton nets).
To check the possibility of sampling bias, studies were also conducted
to contrast day and night sampling efforts and densities in different strata
of -the water column. One important conclusion emerged from studies of verti-
cal distributions near the Monroe Power Plant. The larvae of all abundant
fish species concentrated near the bottom during the day and dispersed through-
out the water column at night. These results imply that the catch of daytime
oblique tows especially depend on the effectiveness of the gear next to the
bottom where the larvae concentrate.
Any interaction of technique effectiveness with habitat variation related
to distance from shore could produce a spurious relationship between larval
density and distance from shore. Depth, turbidity and turbulence are all
likely to vary directly with distance from shore and could influence gear ef-
fectiveness during daytime studies. Without a bottom-sled, it is much easier
to continuously tow a meter-net close to bottom and catch more larvae in water
one to two meters deep than in water several meters deep. If visibility en-
ables larvae to avoid nets, as indicated by Noble (1969), turbidity gradients
may disproportionately favor shoreline capture during daytime sampling. On
the other hand, if strong turbidity gradients do not exist, fish in deep, dark
water may be more susceptible to capture than fish in shallow illuminated
water. Wind-generated turbulence is also more likely to vertically mix larvae
close to shore than farther from shore and increase the probability of capture.
Interactions of gear effectiveness with depth, turbidity and turbulence
should be minimized at night, when the larvae are dispersed through the water
column and visability is limited by darkness. In accordance with this logic,
a nighttime sampling effort was designed to investigate larval fish density
gradients related to distance from shore.
Larval fish were also sampled in the flooded tributary valleys and back
waters behind the beach to contrast with samples obtained from along the
beach front and further offshore. Although tributaries and marshy back waters
have been claimed to be important nurseries (Troutman, 1957; 6LBC, 1975), no
previous sampling in Lake Erie has attempted to quantify the relative densi-
ties of larval fish in these environments. Larvae that concentrate in quiet
back waters may be relatively invulnerable to entrainment at intakes which
open into the main water body. Concentrations of larvae were also estimated
in the cooling system of the Monroe Power Plant to compare to densities of
larvae captured in the lake and peripheral back waters. The mortality of en-
trained larvae was also estimated at night to contrast with previous estimates
of daytime mortality reported by Cole (1976a).
Although the results of these studies tend to confirm the importance of
the shorezone for spawning of some fish species, older larvae and important
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fish food organisms appeared not to be consistently concentrated near shore
except for the species which concentrated in backwater regions. These results
are believed to be more representative of distributional trends than studies
that relied solely on oblique, daytime tows.
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SECTION 2
CONCLUSIONS
1. The prolarval distributions of most species may have reflected locations
of major spawning activity. Maumee Bay appeared to be particularly im-
portant for prolarval clupeids, freshwater drum and white bass.
2. In Lake Erie proper, densities of post larval larvae were highly varia-
ble, but these larvae tended to be dispersed over the entire study area
without exhibiting any strong concentration gradients.
3. In night studies of lake distributions, only prolarval yellow perch ex-
hibited consistently high concentrations along the beach fronts. Although
frequently aggregated, older perch larvae, like other postlarvae of abun-
dant species, including clupeids, rainbow smelt, shiners, white bass and
freshwater drum, were widely dispersed over the study area.
4. In the daytime bottom-sled tows, species other than rainbow smelt, fresh-
water drum and postlarval yellow perch were often 10 or more times more
abundant in the flooded tributaries than in lake water 5 to 6 m deep.
5. In the lake, nighttime sampling with oblique tows of a 361-y, 1-m net
was more effective for fish larvae, midges and Leptodora kindtii (yielded
more animals per unit folume filtered) than day time sampling with a bot-
tom sled. The best explanation for the difference seems to be that the
animals are difficult to sample effectively during the day because they
are so closely associated with the bottom.
6. In contrast with the results of oblique night sampling in the lake, day
sampling with a bottom sled indicated higher concentrations near the
beaches for most species. These differences may have been the result of
chance encounters or shore zone turbulence could have increased the rel-
ative rate of capture with a bottom-sled towed near the beach.
7. Day and night captures with oblique tows in the discharge canal yielded
similar total catches, except for the invertebrates which were more
likely to be captured at night. Yellow perch, smelt, carp-goldfish,
white bass and shiners were less concentrated in the discharge canal
than in the lake while clupeids and freshwater drum seemed to be more
concentrated. This may indicate differences in the relative proportions
of fish larvae entrained by the plant.
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A large proportion (80%) of the clupeid larvae appeared to be dead before
they were entrained by the Monroe Power Plant, but most larvae of other
species were alive (>80%). Except for carp-goldfish, most larvae observ-
ed in the discharge canal were dead or dying. Carp-goldfish larvae may
have hatched in the discharge canal.
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SECTION 3
METHODS
DESCRIPTION OF THE STUDY SITE
The sampling was conducted in Michigan and Ohio waters on western Lake
Erie. Mortality studies were completed in the once-through cooling system
at the Monroe Power Plant (Figure 1). The plant generates up to 3100 mega-
watts and uses up to 80 cu m/sec of cooling water. The first of four 800
megawatt units began operating in June, 1971 and the last started in 1974.
Cooling water is warmed 5 to 15 C (depending on time of year and operational
level) and released to Lake Erie via a 1700-m discharge canal.
Cooling water comes from two sources, the Raisin River and western Lake
Erie, which differ both in water quality and composition of larval fishes.
Because of seasonal fluctuations, the river may supply nearly all of the cool-
ing water in late winter and early spring but less than 5% during summer low
flow. The river is more contaminated with biodegradeable organic wastes and
inorganic nutrients than the lake, however both the river and lake are turbid
from suspended matter eroded from the watershed. Concentrations of inorganic
nigrogen (0.5 to 3.0 ing/liter) and total phosphorus (0.1 to 0.2 mg/liter) are
high enough throughout the growing season to maintain dense growths of algae
in both (Cole, 1976a). Organic carbon is about twice as concentrated in the
river as in the lake (0.5 mg/liter). While summer biochemical oxygen demand
occasionally causes anoxia in the river, the oxygen concentration in the lake
exceeds 3 to 4 mg/liter near the bottom except when the lake stratifies during
rare calms. Zooplankton, benthic invertebrates and fish are less abundant in
the river than the lake (Cole, 1976a; Lavis and Cole, 1976; Kelly and Cole,
1976).
SAMPLING
Night Transects
Night sampling was conducted along transects shown in Figure 1, to inves-
tigate the possibility of density gradients in relation to shore and the mouth
of the Maumee River. The transect positions were determined by the presence
of navigational lights on shore and along the navigational channels leading
into the Detroit and Maumee Rivers. Transects A and C were positioned to run
from shore lights to channel lights, transect E ran straight from Stoney Point
to Maumee Bay and transect followed the shoreline (within 0.3 km) from Stoney
Point to Maumee Bay. All sampling was conducted April 27-30, May 17-24, and
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Cooling Syste
MONROE
POWER PLANT
°C
IO
N
10 km
Transects A,C
Transects E,G
Bottom-sled samples
Figure 1. The location of sampling stations and the cooling system at the
Monroe Power Plant, Southwestern Lake Erie.
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June 15-26, 1976. During each of the three sampling trips, transects A and G
were sampled together on two nights and E and G were sampled together on two
other nights (except in June when transects E and G were sampled twice in one
night).
Nighttime distributions were assessed with single, oblique three-minute
tows from bottom to top using a 363-y net at a total of 20 locations (10 per
transect) per evening. It was assumed, as indicated by Cole (1976a), that
at night most larvae were dispersed throughout the water column and equally
susceptable to oblique tows regardless of variation in depth, turbulence or
turbidity. Station positions along the transect were identified by traveling
speed and confirmed by occasional triangulation on shore lights and buoy lights.
Backwater, Beach and Offshore Distributions
Population densities were contrasted in three general habitats: flooded
tributary mouths, along beach fronts and offshore. Because the flooded trib-
utaries were difficult to sample at night, sampling was conducted during the
day with 3-min tows of a 363-y, 1-m plankton net fastened in an aluminum
bottom sled. Cole (1976a) had demonstrated that most of the larvae were con-
centrated near the bottom during the day, indicating that bottom sampling was
the best way to contrast larval densities if sampling had to be conducted dur-
ing the day.
The stations sampled are identified in Figure 1. Only one sample was
taken from each station on each sampling date, for a total of 5 samples per
habitat type: in protected backwaters and river mouths (1 to 2-m deep), off
beach fronts (1-m deep) and about 1-km offshore (5 to 6 m deep). All sampling
was conducted on April 27-30, May 17-24, and June 15-26, 1976. Samples were
collected oh 2 dates within each of the 3 sampling trips for a total of 6
times. Sampling stations along the beach and offshore closely coincided with
specific nighttime sampling stations and these were contrasted to compare the
techniques.
Studies in the Power-Plant Cooling System
Larval fish densities in the discharge canal were sampled both day and
night to contrast with estimates made in the lake and peripheral waters.
Density was estimated from 5 oblique tows of a 363-y net on each day and night
sampled. Mortality was also estimated at night to contrast with 1975 esti-
mates made during the day and reported by Cole (1976a). Other than the time
of day sampled, the technique was as described by Cole (1976a). Mortality
was estimated on two days and nights during each of the three sampling trips.
8
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SECTION 4
RESULTS
OVERVIEW
Fifteen taxa of larval fish were captured during the study period (Table
1). Several taxa could not be identified confidently to the species level
because of larval similarities during certain developmental stages. Based on
proportions of adults collected in the area from 1970 to 1975 (Lavis and Cole,
1976), the unclassified clupeid larvae were mostly Dorosoma cepedianum and the
shiner larvae were mostly Notropis atherinoides and Notropis hudsonius. Close
to even proportions of adult carp and goldfish inhabited the area. Two taxa
of large invertebrates were also included in the analysis because of their
potential importance as fish foods: Chironomidae and Leptodora kindtii. Chir-
omonidae included larvae and pupae of several unclassified taxa.
Table 1 summarizes the mean yield per-unit effort in daytime, bottom-sled
tows and oblique tows in the discharge canal (day and night) and the lake
(night only). Night sampling with oblique tows in the lake yielded higher
concentrations of animals than efforts with a bottom sled or oblique tows in
the discharge canal. More species were caught in the lake at night but this
may have been a result of greater sampling intensity.
RATIOS OF PROLARVAE TO POSTLARVAE
Table 2 summarizes the relative ages of larvae captured in the night tows,
the bottom-sled tows and in the discharge canal. In April, the preponderance
of the catch were prolarvae except for the few postlarval walleye. For the
most part, ratios of prolarvae and postlarvae were similar in the nighttime
oblique tows and the daytime bottom tows taken from the lake, but ratios of
clupeids and yellow perch in the discharge canal appeared to differ from lake
ratios. Yellow perch larvae in the canal averaged older than lake larvae
while clupeid larvae in the canal averaged younger.
At any particular sampling time, the average age of larvae caught in the
different sampling programs varied inconsistently; but the average age of
yellow perch, clupeids, rainbow smelt and most of the rarer species increased
from April to June. Many of the rare species were captured primarily as post-
larvae, perhaps because their hatching was closely spaced just after the May
sampling and several weeks before the June sampling; some fish (sunfish, chan-
nel catfish, black bass, crappie) remain in redds during prolarval stages.
These inconsistent differences in the ratios of prolarvae to postlarvae were
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TABLE 1. MEAN NUMBER OF ANIMALS/100 M CAUGHT IN ALL. TOWS MADE IN THE CANAL,- BOTTOM SLEDS AND NIGHT "TOWS IN
THE LAKE
APRIL (26-29)
Species
Yellow perch
Perca flavesaens
Rainbow smelt
Osmevus movdax
Clupeid
. DoroBoma aepedianw
Alosa pseudoharengua
Walleye
Stizoetedion vitreum
Carp-goldfish
Cyprinus oorpio
Cofa88i.ua aupatue
White sucker
Catostcmts cormersoni
White bass
Morone ahrysops
Shiners
Notpop-Ls atherinoides
Notropi-s hudsonius
Notropis' QomutaB
Freshwater drum
' Aplodinotus gvimniena
Log perch
Peroina aaprodes
Trout perch
Peraopsis omiBcomayaue
Daytime
Bottom
Sled1
n=30
21.5
0.5
0.5
0
0
0
< 0.1
< 0.1
0
, 0
0
Night
Lake
Oblique2
n=80
44.2
1.1
1.9
0.2
0.1
0.4
0
0
0
0
0
Day&Night
Discharge
Oblique3
n=20
0.7
0
33.0
0
0
<0.1
0.2
0
0
0
0
MAY
Daytime
Bottom
Sled
n=30
1.5
2.7
45.1
0
0.3
0
0.1
0.2
0.1
0
0
(16-26)
Night
Lake
Oblique
n=8o
2.3
15.2
65.4
0
0.5
0.2
7.8
0.1
0.1
0.4
0.2
JUNE (14-26)
Day&Night
Discharge
Ofallqur
n=20
1.3
0
112.6
0
0.1
0.1
0.2
0
0.9
<0.1
0
Daytime
Bottom
Sled
n=30
0.2
0.6
460.2
0
10.3
0
5.7
5.3
0.7
0
0
Night
Lake ?
Oblique
n=75
0.4
2.4
251-4
0
3.2
0.5
1.6
36.0
2.1
0.3 .
0.1
Day&Night
Discharge
Oblique3
n=20
0
0
103.7
0
0.3
0
1.3
16.0
0.2
0
0
(Continued)
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TABLE 1 (continued)
APRIL (26-29) MAY (16-26)
Daytime
Bottom
Sled
Species n=30
Sunfish 0
Lepomis macpoahivus
Lepomis gibbosus
Channel catfish 0
lotalurus punatatus
Black bass 0
Mioropterus dolomieui
Miepopterus salmoides
Crappie 0
Pomoxis armularis
Leptodora kindtii 0
Chironomidae 0
JUNE (1^-26)
Lake Day&Night Daytime Lake Day&Night Daytime Lake Day&Night
Night Discharge Bottom Night Discharge Bottom Night Discharge
Oblique Oblique3 Sled Oblique2 Oblique3 Sled Oblique2 Oblique3
n=80 n=20 n=30 n=80 n=20 n=30 n=8a n=20
0 0 0 0.1 0
00 000
0 0 ' 0 0 0
00 000
0 0 1231 2118 170
0 0 0.3 390 1.6
1.3
0
0
0
1*217
107
1.1
0.2
< 0.1
< 0.1
27129
2369
0.3
0.3
0
0.2
235^
805
A bottom-sled with a 36l-n 1-m plankton net was towed during daylight hours.
2
Night tows in the lake were made with oblique tows of a 36l-u, 1-m plankton net.
In the discharge canal, oblique tows were made both day and night.
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TABLE 2. RATIOS OF PROLARVAL AND POSTLARVAL STAGES IN DIFFERENT SAMPLING EFFORTS FROM APRIL TO MAY, 1976
H
NJ
Bottom
Species Tows
Yellow perch 317.5:1
Clupeids 3.8:1
Smelt 17:1
Sucker 6.0
Carp-goldfish 16.0:0
Walleye
White bass 2:0
Shiner 1:0
Log perch
Sunfish
Freshwater drum
Trout perch
Channel catfish
Crappie
Black bass
APRIL - MAY
Lake -Lake
Night Discharge Bottom Night
Tows Canal Towe Tows
351.0:1 17:0 0.6:1 0.5:1
3.0:1 795:0 16.2:1 3.U:1
l»2.0:l 1.6:1 0.3:1
3.U:1 1U.O:0
9.0:0 8.0:0 9.0:0 lU.O:0
0:5
0:3 1.8:1
6:0 1.2:1
1:3 2U:0
U:0
1:0 2.5:1
5:0
Discharge Bottom
Canal Tows
5-3:1 1:1
12.1:1 0.1*:1
0:21
2.0:1
10.0:1 33.7:1
1:3 0.1:1
1:0 0.5:1
•1:0
0.2:1
18:0 2.5:1
5-0
0:12
JUNE
Lake
Night
Tows
5:1
0.1:1
0:150
0:6
2.8:1
0.22:1
0.07:1
0.3:1
0:15
5.6:1
0:3
0:15
0.3:1
0:6
Discharge
Canal
0.1:1
22.0:1
0.20:1
38.0:1
0:6
0:3
0:6
3:0
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not associated with particular sites (inshore versus offshore) or particular
sampling techniques, and probably were caused by the patchy distribution of
different-aged cohorts.
BOTTOM SLED STUDIES
Results from bottom-sled tows offshore, along the beach and in flooded
tributary valleys indicated that the larvae of most species were distributed
differently among these three different habitats (Table 3). But the vari-
ability among samples within habitats was too great to regularly identify
statistically significant (a « .05) differences among inshore, beach and off-
shore zones. When enough individuals were captured to establish a trend,
density gradients appeared to exist in most species. Concentrations along
the beach or in tributaries were often 10 or more times greater than offshore
concentrations for most species. Only rainbow smelt, postlarval yellow perch
and possibly freshwater drum, seemed to be as abundant offshore. For those
species that were concentrated inshore, most seemed more abundant in the
flooded tributary mouths than along the beaches.
Neither Leptodora kindtii nor midge larvae consistently exhibited density
gradients related to shoreline proximity and their patterns seemed to reflect
patchiness. Although in May, L. kindtii seemed concentrated inshore, in June
they seemed more abundant offshore.
DAYTIME BOTTOM TOWS VERSUS NIGHTTIME OBLIQUE TOWS
Among stations which were sampled both with daytime sled tows and night-
time oblique tows, night sampling tended to be more effective (Table 4) for
most species. The total nighttime yield of larvae, midges and Leptodora
kindtii was about an order of magnitude more than daytime yield with a bottom-
sled. Only yellow perch and rainbow smelt larvae were captured in larger
numbers with daytime bottom-sled tows, and those could have been chance en-
counters with dense aggregates. The difference between day and night tows
could be explained by differences in net avoidance during light and dark hours,
at least in the shallow water along the beach. Offshore, however, tows were
made in water deep enough (5 m) to nearly eliminate day and night differences
in the amount of light reaching the bottom. Catch ratios for day and night in
May and June were similar in deep, poorly lighted waters and shallow well-
lighted waters, therefore differences in visibility appeared not to be the
major cause of catch differences. A more probable explanation is that the
animals were so closely associated with the bottom during the day that most
remained below the rim of the sled-mounted net (about 20-cm gap existed be-
tween the rim and the bottom).
DISTANCE FROM THE MAUMEE RIVER AND THE CLOSEST SHORE
Transects A, C, E and G were sampled with oblique night tows to assess
the relationship of larval fish distributions to distance from the closest
13
-------
TABLE 3. MEAN NUMBER OF ANIMALS/100 M3 CAUGHT DURING THE DAY WITH A BOTTOM-SLED TOWED IN PROTECTED
INSHORE WATERS (FLOODED TRIBUTARY MOUTHS) ALONG THE BEACHES AND IN DEEPER WATER 1 TO 2 KM
OFFSHORE. BEACH AND INSHORE WATERS WERE 1 TO 2 M DEEP AND OFFSHORE WATERS WERE 4 TO 6 M DEEP
Species
Clupeids
Yellow Perch
Smelt
Carp-goldfish
White bass
Shiners
Freshwater drum
Sunfish
Leptodora kindtii
Midges
April 27 &
Inshore Beach
0
30.
0.
0
0.
0
0
0
0
0
0.1
0 21.2
3 1.1
0
1 0
0
0
0
0
0
29
Offshore
1.3
13.3
0.2
0
0
0.1
0
0
0
0
May 17 &
Inshore
106.9
0.9
2.6
0.9
0.3
0.5
0
0
Beach
23.2
1.1
0.7
0
0.1
0.1
0
0
241.7 1132.0
0.3
0.3
18
Offshore
5.1
2.6 .
4.9
0
0
0
0.2
0
2319.1
0.3
June 15 &
Inshore
1163.2
0
0
19.1
13.5
5.2
0.9
3.2
6359.4
87.6
Beach
190.8
0.5
0.3
11.8
3.6
10.8
0.3
0.3
2613.4
194.4
17
Offshore
26.7
0
1.6
0
0
0
0.8
0.3
3679.0
40.0
Tlean of 5 samples on each of 2 dates; n = 10. Samples were taken at stations a to e shown in Figure 1
-------
TABLE 4. MEAN NUMBER OF ANIMALS/100 M CAUGHT AT STATIONS SAMPLED WITH DAYTIME, BOTTOM-SLED TOWS AND NIGHT-
TIME OBLIQUE TOWS WITHOUT A BOTTOM-SLED
BEACH (<1.5 m deep)
April
Species n =
Yellow perch
Clupeid
Smelt
Carp-goldfish
Sucker
Shiner
Freshwater drum
Log perch
White bass
Trout perch
Sunfish
Total
Midges
Leptodora
Night
10
236.2
0.3
0.3
0.2
2.3
0
0
0
0
0
0
239-3
^
T-
Day
10
21.2
0
1.1
0
0
0
0
0
0
0
0
22.2
-
May
Night
10
1.6
12.9
1.0
0.1
0.7
O.U
0
0
1.0
0
0.3
18.0
123.0
22^0
Day
10
1.1
0
0.7
0
0
0.1
0
0
0.1
0
0
2.0
0.3
1332
June
Night
10
0.1*
501.7
0
1.6
0.5,
U.3
0.2
0
3.7
0
0
512.1*
361*9
31*831
Day
10
0.5
0
0.3
11.8
0
10.8
0.3
0
3.6
0
0.3
27-6
19!*
2613
OFFSHORE ( 1*
April
Night
10
1.1*
0.3
0.8
0
0
-
0
0
0
0
0
2.5
Day
10
13.3
0
0.2
0
0
0.1
0
0
0
0
0
13.5
to 6
May
Night
10
1.6
37.6
28.3
0.1*
0
0
0.2
1.0
11.1
0.3
0
90.U
528
Day
10
2.6
0
1*.9
0
0
0
0.1
0
0
0
0
7.6
0.3
, 1^1*1* 2319
m deep)
June
Night
10
0
73.5
5-8
0
0
10.0
0
0
0.5
0.5
0
90.3
2505
31*912
Day
10
0
0
1.6
0
0
0
0.8
0
0
0
0.3
2.7
1*0
3679
-------
shore and distance from the Maumee River. Some of the common species; par-
ticularly larval cupeids, white bass, and freshwater drum, were most abundant
near the Maumee River during prolarval stages (Figure 2, Table 5). Although
prolarval yellow perch (in April samples) were concentrated in Maumee Bay,
they were more abundant in other shallow waters (Transect G) 10 to 14 km
north of the Maumee River, where several smaller tributaries enter Lake Erie.
When postlarvae dominated the catch, no species appeared to be uniquely con-
centrated in Maumee Bay. Although postlarval clupeids were common in Maumee
Bay, they were also relatively abundant all along the west shore, north of
the bay. Apparently, the larvae of any species that spawned predominantly
in the Maumee River or Maumee Bay were widely and rapidly dispersed over the
study area as they grew into postlarval stages.
Larvae of rare species were dispersed widely over the study area, with
the possible exception of the log perch which seemed less common near Maumee
Bay than in the deeper water of Brest Bay about 10 to 15 km north of Maumee
Bay (Table 3). Neither midges nor Leptodora kindtii exhibited any consistent
spatial trends, except in May when midges appeared to be more concentrated in
Maumee Bay. Like most prolarval fishes, both invertebrate taxa exhibited
aggregated distributions.
Of all the larvae sampled with oblique night tows, only prolarval yellow
perch were generally concentrated close to the beaches along shore (Figure 3,
Table 6). The other animals appeared to be dispersed over the study area,
often in aggregations, without any indications of concentration gradients.
The density estimates were particularly erratic for postlarval clupeids,
Leptodora kindtii and midge larvae. Smelt may have been more abundant off-
shore and none of the rare species seemed to be particularly concentrated
near shore.. Even the larvae of species that are marsh or beach spawners
(black bass, sunfishes, crappie, carp-goldfish) were captured several kilom-
eters from shore, often in small aggregations.
Discrepancies occurred between daytime bottom-sled tows and the night-
time oblique tows for clupeids, carp-goldfish, and shiners. Oblique night-
time tows failed to confirm the daytime bottom-sled indications that these
taxa were more abundant near the beach than offshore. The different results
may be caused by unknown depth-related differences in the sampling effective-
ness of these methods or by chance encounters with aggregations in different
parts of the study area. During the day, differences in visibility would ap-
pear to favor higher captures offshore rather than nearshore, if the larvae
were evenly distributed (as indicated by oblique tows at night). Possibly,
turbulence had a greater impact on vertical distributions inshore than it did
offshore. Turbulence would tend to lift larvae off the bottom and into the
sampled water column. Depending on wind conditions, relatively small differ-
ences in depth could produce large differences in turbulence near the bottom
where larvae congregate. The comparison of day and night efforts in Table 3
supports the idea that chance encounters with aggregations caused the apparent
concentrations near shore. Night catches at those selected stations also in-
dicated that clupeids, carp, goldfish and shiners tended to be more common
near the beach on some dates.
16
-------
10
I0j
200
"°6 150
o
^ 100
g. 50
• TRANSECT E-F CARP-
A TRANSECT G-H (
• - A- - A« A A. . A - A-
SMELT
A.* A. A A* A • A A^ A • A • ^ A
GOLDFISH
JUNE)
K •
(APRIL)
A«
SMELT (MAY)
o:
Lu
CD
13
10.
300.
200.
100.
10.
• •* A A A A A A A A*
..-*-. SMELT (JUNE)
• • % • •
.A A AA A A A A • » A*
* YELLOW PERCH
(APRIL)
,
.. X
YELLOW PERCH
2468 10 12 14 16 18 20 22 24
KM
Figure 2. Mean number of larval fish, larval midges and Leptodora
kindt.ii in relation to distance (km) from the mouth of
the Maumee River. Each recorded point represents the
mean of all observations made at that distance from
the Maumee River during the sampling expedition.
17
-------
•E
O
O
200
150
100
50
100
30
20
10
g. 1000
B ^^
g 600.
§ 400.
200.
800.
600.
400.
200.
WHITE BASS (MAY)
• TRANSECT E-F
A TRANSECT G-H
WHITE BASS (JUNE)
CLUPEIDS (APR1U
CLUPEIDS (MAY)
CLUPEIDS (JUNE)
* A
2 4 6 8 10 12 14 16 18 20 22 24
KM
Figure 2 (continued)
18
-------
15.
10.
5.
50.
40.
30.
20.
"fe 10.
<5
g 80.
5 60.
2 40.
20.
160.
140.
I2Q
V IT^KIIS 1-H MIDGES (MAY)
\\
O\ ^ s-~S N.--
xv-'»^-.:'; .*_ .--»--*
*-.A-" m~~~A->"
16^
^»
•
• MIDGES (JUNE)
. *•
• • A
A A •
A * A * • A
•
• LEPTODORA
A (MAY)
A* A* A
• A A A •
A * '
• A- •
A . LEFTODORA
A A A. (JUNE)
A •
• * "
' • 4 »
I I
2 4 6 8 10 12 14 16 18 20 22 24
KM
Figure 2 (continued)
19
-------
TABLE 5. MEAIT NUMBER OF LARVAE/100 M3 FROM SCARCE SPECIES CAUGHT ALONG TRAN-
SECTS E AND G PARALLEL TO SHORE IN NIGHT TOWS
Species
Stations
8
10
APRIL (21 & 29)
White sucker
Carp-goldfish
Walleye
MAY (2k & 26)
White sucker
Trout perch
Carp-goldfi sh
Shiners
Freshwater drum
Log perch
Sunfish
JtmE (21)
White sucker
Trout perch
Freshwater drum
Yellow perch
Mean
0.68
0.25
0.25 0.25, 0.23
0.83 0.23
0.1*3 0.23
0.83
0.87
1.1*0 1.80 0.90
5-5 0.25 0.1*5 O.U8
0.1*3 0.20
0.60
0.1*3
0.77
1.1*3 0.25
1.0
0.38
0.25 1-70 U.33 0.73
0.65
0.53 0.83
0.60
0.50
of four separate tows
20
-------
140.
130.
120.
110.
IOO.
90.
80.
70.
pO_
|eo.
g50.
$.40.
85 30.
CD
220.
Z 10.
15
i v/ •
10.
5.
f YELLOW PERCH
(APRIL)
1
l
1
i
l
1
1
*
\
\
\
x%^,« 0 *•
YELLOW PERCH
• MAY
A JUNE
A ' A A •
• * «^ «.••*••. • • \ •. • •
1 2 34 567
KM
Figure 3. Mean number of larval fish, larval midges and .
Leptodora kindtii in relation to the closest dis-
tance (km) from shore. Each recorded point repre-
sents the means of all observations made at a
specified distance from shore during the sampling
expedition.
21
-------
10.
5,
600.
500.
400.
„ 300.
Q 200.
S. IOQ
H 800.
i 700.
600.
500.
400.
300
200.
100
CLUPEIDS (APRIL)
— •-. ^ .*_* .._^..
•1150
CLUPEIDS (MAY)
•
•. • •*
i» •»-.-- •_••• •
*II2° CLUPEIDS (JUNE)
.
• •
• •
. . * . •• '
•*._.•••.
1234567
KM
Figure 3 (continued)
22
-------
20.,
SMELT (APRIL)
IOJ
o Q-fi .*^* ••• -•*•"• — • * «•» ••••, ••
o
40. SMELT (MAY)
o>
CL
E 30.
CD
=
20J
IOJ
• • •
• • • •
m, •• •- . m _
loj SMELT (JUNE)
3 4 5
KM
Figure 3 (continued)
23
-------
SHINERS (JUNE)
80.
60.
20
8 20
S. 10
*% . ^ *. • -* *••--•
CARP-GOLDFISH (JUNE)
" • •'. •
_«•—•—!!—
WHITE BASS (MAY)
100
z
80
60
40
20
|Q WHITE BASS (JUNE)
,, « > » t,f '.*tf^ * p
3 4
KM
Figure 3 (continued)
24
-------
80.
70,
60.
50.
40.
to 30.
E
- 20.
IQ
§
g 800.
700.
600.
500.
400.
300.
200.
100.
• .
LEPTODORA
(MAY)
..
•
•
. •
•• .« • • •
• . * •• ••• • • •
. LEPTODORA
• (JUNE)
•
•
•• •••.*••
*• • • • • * •
1 2 3456 7
KM
Figure 3 (continued)
25
-------
700.
600.
500.
40O.
ro
e 300.
o
g 200.
I 1000.
i 900.
800.
700.
600.
500.
400.
300.
200.
100.
• 1037 • MIDGES (MAY)
1719
• .
• * • 9
* . «632I
MIDGES (JUNE)
0
• •
*
• •
*• * • *
,t . , 1 — ' 1 1 —
23 4567
KM
Figure 3 (continued)
26
-------
TABLE 6. MEAN NUMBER OF SCARCE LARVAE/100 M3 FROM SCARCE SPECIES CAUGHT AT
DIFFERENT DISTANCES FROM SHORE IN NIGHT TOWS
n = 26
APRIL (26,27,28,29)
White sucker 0.90
Walleye
Carp goldfish 0.09
MAY (16, 18, 24, 26)
White sucker 0.26
Carp-goldf i sh 0.22
Trout perch 0,03
Shiners
Log perch 0.11
Freshwater drum
Sunfish 0.70
Channel catfish
JUNE (lU,21,26)
White sucker 1.00
Trout perch
Log perch
Freshwater drum 1.05
Sunfish
Yellow perch 0.05
Channel catfish
Black "bass
Crappie
VI
0.14
0.28
0.11
0.13
0.11
0.46
0.93
0.22
0.63
0.37
Km from Shore
2s3 V T?? ¥ V
0.10 0.45
0.09
0.45
0.15 0.78
0.23
0.19 0.15
0:98 2.88
0.55
•
1.71 0.52 0.45
0.23
1.00 0.3^
0.39 1.20 1.09 0.81 1.03
0.60 1-83
1.80 3-10
0.39
27
-------
CAPTURE IN THE DISCHARGE CANAL
Day and night oblique tows in the discharge canal yielded similar total
catches of fish larvae (Table 7). The catch of all common species varied
widely without consistent relation to day and night. Most of the rarer
species were captured during one or two sampling efforts and may have repre-
sented chance encounters unrelated to the time of day. The invertebrates
were more likely to be captured at night during June, particularly the midges
(mostly ChaoJborus), but the May samples indicated no diurnal differences.
The average concentration of the total larval catch in the discharge
canal did not differ greatly from the estimated lake concentration. However,
certain species seemed much less concentrated in the discharge canal than in
the lake, including yellow perch, smelt, carp-goldfish, white bass and shiners.
At times, clupeids and freshwater drum also seemed to be more concentrated in
the discharge canal than in the lake. Among rare species, the numbers captur-
ed were too few to identify differences between lake and discharge concentra-
tions .
MORTALITY
The results (Table 8) of the mortality study are of limited value for
the effort expended. Sampling variability was too great to identify statis-
tically significant (a = 0.1) differences. Only two taxa, clupeids and carp-
goldfish, were captured in large enough quantities in 1975 and 1976 to make
reasonable, taxa-specific contrasts between years. For clupeids, intake
samples had a much higher proportion of immobile and opaque larvae in 1976
compared to 1975. Even though 1976 samples were taken at night and 1975 sam-
ples were taken during the day, the differences between years were not neces-
sarily related to the time of sampling. There may be considerable temporal
variability in the proportion of dead larvae observed in natural populations.
The cause of the high mortality was unknown but apparently it was natural and
species specific.
Except for carp-goldfish, most of the larvae observed in the discharge
canal were dead or dying. The observed differences between the discharge
canal and the intake, are assumed to be caused by condenser passage. The
relatively high proportion of apparently healthy carp-goldfish larvae may
have been caused by successful hatches in the discharge canal.
28
-------
TABLE 7. MEAN NUMBER OF ANIMALS/100 M3 CAUGHT IN DAY AND NIGHT INTEGRATED TOWS IN THE DISCHARGE CANAL AT THE
MONROE POWER PLANT
ro
vo
APRIL
Species
Clupeid
Yellow perch
Shiner
White bass
Carp-goldfish
Sunfish
Freshwater drum
Log perch
Channel catfish
Sucker
Crappie
Total
Midges
Leptodora kindtii
Day
27 29
10.3
0.2
0
0.6
0
0
0
0
0
0
0
10.5
J
0
20.0
2.2
0
0
0
0
0
0
0
0
0
22.2
0
0
Night
28 30
3.8
0.2
0
0
0
0
0
0
0
0.2
0
1*.2
0
0
97.8
0.3
0
0
1.2
0
0
0
0
0
0
99.3
0
0
17
179-9
0.2
0.3
0.7
0.6
0
0
0.2
0
0
0
181.9
2.2
50
Day
18
107.5
3.5
0
0
0
0.
0
0
0
0
0
111.0
0.2
101
MAY
Night
16 21*
lUl.8
0.6
0
0
1.5
0
3.5
0
0
0.2
0
11*7.6
0
U61*
21.2
0.7
0
0.2
0
0
0
0
0
0.3
0
22.1*
3.8
66
Day
11*
131.2
0
62.2
1.7
0
0
0
0
0
u
0
195-1
0
1066
131
9
0
1
0
0
0
0
0
0
0
JUKE
MEAN
Night
15 17 26
.6 ll*6.U
0
0
.0 1.9
0.6
.6 0
0
0
0
0
0
133.2 11*8.9
17
1391*
168.0
21*20
5-5
0
1.8
0.6
13.3
0.6
0.6
0
1.2
0
0.6
2l».2
3201.0
1*537
Day
96.8
1.2
10.1*
0.7
0.1
0.1
0
<0.1
0
0
0
109.0
3.2
1*35-2
Night
69.1*
0.3
0
0.5
2.8
0.1
0.7
0
0.2
0.2
0.1
71*. 9
562.1
11*97-1*
-------
TABLE 8, ESTIMATES OF MORTALITY IN THE ONCE-THROUGH COOLING SYSTEM OF THE MONROE POWER PLANT DURING 1975
(DAY TIME) AND 1976 (NIGHTTIME) SAMPLING PERIODS
INTAKE
Species
Clupeid
Yellow perch
Carp-goldfish
All other larvae
Total larvae
Day
Dead/.
Total"1
0.15
0.20
0.09
0.17
0.16
1975
Number
Caught
66
ko
20
50
176
Night
Dead/
Total
0.80
0.19
0.20
0.00
0.36
1976
Number
Caught
3U
28
12
5
79
Day
Dead/
Total
0.79
0.72
0.27
1.00
0.75
DISCHARGE CANAL
1975
Number
Caught
11
5
6
5
29
Night
Dead/
Total
0.86
-
0.06
-
0.59
1976
Number
Caught
l»0
0
18
1
59
itio of immobile and opague larvae to total catch of alive and dead.
-------
SECTION 5
DISCUSSION
SPAWNING AND NURSERY AREAS
Knowledge of the relative utilization of different coastal-zone habitats
for fish spawning and nurseries is indispensable for any reasonably planned
coastal development, including power production. Undoubtedly, many of the
species present in the southwestern corner of Lake Erie spawn close to shore
over shallow beaches and bars, in the mainstream of tributaries, or in the
peripheral backwaters of the lake and flooded-tributary valleys (Scott and
Grossman, 1973; Troutman, 1957). But of all the lake habitats, those near
shore are most likely to be recognized as nurseries or spawning areas by
casual observation. Until recently, too few data existed to quantify the
relative importance of inshore spawning versus offshore spawning in deeper
waters. Even less confidence could be placed on assertions of the relative
nursery value of inshore and offshore waters.
The distribution of prolarvae in southwestern Lake Erie suggests the
relative value of different spawning habitats for some of the abundant species.
The prolarvae of several species seem to be concentrated along certain por-
tions of the shoreline. Prolarval yellow perch seemed to be the most widely
distributed species along the shores. Either yellow perch spawned over a wide
range of beach and backwater habitats, or their eggs and larvae were dis-
persed over those habitats soon after spawning.
Other species appeared to spawn primarily in the Maumee Bay region or
some of the smaller tributaries entering along the west shore. Clupeids and
white bass seemed to originate particularly in Maumee Bay or the Maumee
River; especially, early in the spawning season. As the spawning period
progressed, most clupeid larvae appeared to hatch in or near tributaries along
the west shore. Based on reported spawning habits (Scott and Grossman, 1973),
the prolarval clupeids had hatched on shallow bars and shoals at the mouths
of the tributaries and white bass had drifted out of the tributary mainstreams.
Freshwater drum also could have spawned mostly in Maumee Bay, but even as pro-
larvae, they were widely dispersed over the study area. Their floating eggs
are adapted for rapid dispersal by wind-generated currents (Scott and Grossman,
1973).
Smelt did not appear to spawn in the Maumee River, in any of the smaller
tributaries, or along any shorelines in the southwestern part of the basin.
Smelt were widely distributed over the study area, primarily as postlarvae
that could have been carried long distances by currents. Studies of lake
31
-------
hydrodynamics indicate the dominant influence of the Detroit River (Kovacik,
1972; Walters et al., 1972; Ecker and Cole, 1976) which may he the major
source of smelt larvae. Cole (1976) concluded that concentrations of smelt
progressively increased offshore from Stoney Point, probably in waters de-
rived from the Detroit River.
Shiners, like the clupeids, purportedly spawn over bars and beaches
(Scott and Grossman, 1973) and catches in bottom-sled tows agree with this.
Shiners appeared to use the flooded tributary mouths nearly as much as the
beach sites, and were not exceptionally abundant in the Maumee Bay area.
Carp-goldfish appeared to spawn mostly in the backwaters and protected
shallows, in keeping with putative habits (Scott and Grossman, 1973). In the
lake proper, carp-goldfish larvae were widely dispersed revealing no important
gradient in spawning habitat or nurseries outside the protected peripheral
waters. This also seemed true for the centrarchids and ictalurids which are
believed to spawn predominantly in protected littoral waters and tributaries
(Troutman, 1957; Scott and Grossman, 1973). Except for sunfish, very few
ictalurids and centrarchids were captured in the flooded tributaries. Pos-
sibly, most of those larvae inhabit the heavily vegetated margins of tributa-
ries and backwaters when they were inaccessible to our sampling gear. Depen-
ding on the spawning sites chosen, some species are more likely to be flushed
from peripheral waters into the lake. Species that spawn in the mainstream
of the tributaries (like white bass, channel catfish, white sucker and walleye)
or in the open waters of the flooded-tributary mouths (like yellow perch,
clupeids, or shiners) may be prone to early, prolarval dispersal into the lake,
particularly during spates. On the other hand, prolarvae of species that spawn
in the protected margins of back-waters, such as the carp-goldfish, centrar-*
chids, and bullheads, are much less likely to be flushed into the lake as pro-
larvae.
As the larvae of most species age, they tend to be dispersed over the
study area. Postlarval yellow perch do not remain in the sampled backwater
areas; in fact, concentrations appeared to be higher in the lake proper. Cole
(1976a) indicated that large numbers of yellow perch may enter the western
basin with water from the Detroit River. In contrast, the backwaters appear
to serve as important nurseries for post larval clupeids, sunfish and white
bass. Carp-goldfish probably remain in tributary backwaters through postlar-
val stages. Although low yields of postlarvae prevented confirmation, Lavis
and Cole (1976) found that young-of-the-year carp and goldfish were much
scarcer than older age classes in the lake portion of the study area. Appar-
ently, young carp and goldfish survive mostly in the inaccessible backwater
areas and few of those that drift into the lake survive. The larvae of other
littoral species also may suffer from high mortality when they are flushed
into limnetic waters of Lake Erie.
VULNERABILITY TO ENTRAINMENT
Those fish species that spend most of their early lives along beaches
rather than in protected backwaters or offshore should be particularly vul-
nerable to entrainment at shoreline intakes. Information on the relative
32
-------
concentrations of larvae in lake tows and in the cooling system at the Monroe
Power Plant indicate the relative vulnerability of larvae to entrainment.
Smelt, log perch, trout perch and older yellow perch appeared to be less con-
centrated in the discharge canal and less vulnerable to entrainment because
they were more abundant offshore than inshore. Also, carp-goldfish, white
bass, sunfish, suckers and young yellow perch appeared to be less vulnerable
to entrainment because they were concentrated along distant beaches or in
remote backwaters of tributaries. Cooling system concentrations were similar
or higher than lake concentrations for shiners, clupeids, fresh water drum,
crappie and channel catfish. Some of these species appeared to be vulnerable
to entrainment because they were more concentrated inshore than offshore.
However, species like channel catfish may successfully live and spawn in the
discharge canal (Nelson and Cole, 1975). Generally, these same relative vul-
nerabilities to entrainment were indicated by studies conducted in 1975 and
reported by Cole (1976a).
The distributions of important fish food organisms in relation to des-
tructive intakes conceivably could affect the trophic base available to fish
in nearby waters. Kenega and Cole (1976) have shown the importance of
Leptodora kindtii and certain midge larvae as food for white bass, yellow
perch, and freshwater drum. They are among the largest invertebrate food
items available to carnivorous fishes in western Lake Erie and are consumed
by a range of fish species of different sizes (Price, 1963). McNaught (1972)
has called attention to the possibility that mortality caused by condenser
passage may be directly proportional to the size of the entrained animal.
Therefore, large invertebrates, important as fish foods, may be particularly
vulnerable to plant operation. Massengill (1976) has reported that entrained
midges were almost all killed by condenser passage at a plant on the Connect-
icut River.
This research indicated that midges and Leptodora kindtii were widely
distributed and not consistently any more abundant near shore than offshore.
Results of this study uncovered no distributional differences among inverte-
brate foods which would influence future power plant siting in the coastal
zone of southwestern Lake Erie. The densities varied from one sampling sta-
tion to another, exhibiting clumped distributions unrelated to those of larval
fish. Because of this clumping subtle density gradients may have been missed
by the sampling effort, particularly in the coastal zone near shore.
Larval fish are difficult to sample because they are rare for their size
and they occur in constantly shifting aggregations. This research has at-
tempted to make some allowances for confounding interactions so as to mini-
mize biases related to sampling depth and distance from shore. Only rudimen-
tary assessments on the effectiveness of sampling techniques in different
environments have been conducted under controlled conditions. Many questions
remain about interactions of habitat and technique, particularly for the very
complex and diverse environments of coastal zones. In contrasting the dark,
flat-bottomed environment of offshore Lake Erie with illuminated, topograph-
ically-complicated, tributary mouths, it seems probable that inshore estimates
are likely to be underestimated by bottom-sled sampling. Currently, there is
no known technique that can effectively sample marsh perimeters, rocky bot-
toms, and open flats so that larval densities can be compared. Only tentative
33
-------
and gross evaluations of coastal zone impacts will be possible until acceptable
techniques are developed.
Erratic year-to-year variation at different sites compounds the sampling
problem. If 5-10% changes in larval survival are biologically significant
as suggested by Jensen (1974) for one fish species, such fine determinations
of differences appear necessary. But the inherently high variability of
larval fish densities may limit the confidence that can be placed in data
interpretation.
Since the larvae are usually clumped, the data usually require trans-
formation before sensitive parametric tests for differences may be applied.
Frequently, data transformation does not correct for heterogeneous variances,
diminishing the possibility of discriminating small (15 to 25%), but poten-
tially important differences.
The clumped distribution of spawning sites probably causes early aggre-
gations of prolarvae in some species. Prolarvae of yellow perch and white
bass particularly appeared to be aggregated more than their postlarvae. Per-
haps as larvae age they are dispersed by currents and tend toward random dis-
tributions, at least until they have developed their locomotive ability enough
to school or uniformly disperse.
In any case, sampling directed at prolarvae may lead to inappropriate
conclusions if the reproductive age class of the species is not fixed until
postlarval or later development. Exceptional, density-independant mortality
in prolarval stages (as from a power plant) may be compensated by lower den-
sity-dependent mortality among the remaining larvae. Sampling may best be
concentrated on the earliest life stage that seems to establish the recruit-
ment into reproductively mature stock (sometime during the first year). Once
that stage is reached, any additional source of mortality may inexorably reduce
recruitment and compete with the fishery.
Possible Interspecific Compensatory Interaction
For wild fish larvae, virtually nothing is known about competition or
vulnerability to predation and disease. It is easiest to assume that any
additional mortality caused by power plants will simply be added to all other
sources of mortality. But is possible that power plant impacts could de-
press the density of certain species and indirectlyj through response to
changed competition, predation, or disease, favor the survival of other
species. The results of this study show that a very abundant species, the
gizzard shad, could be particularly vulnerable to plant operation in south-
western Lake Erie. It is not a particularly desirable species at its present
density in western Lake Erie (Cole, 1976b) and it is possible that, because
of its abundance, gizzard shad population dynamics significantly influence
the survival of sympatric larvae.
Similarly, neither larval disease nor predation are understood. Disease
or starvation may have been responsible for what seemed to be an inordinately
high proportion (80%);of dead and dying clupeid larvae caught in the intake
34
-------
at the Monroe Power Plant. In that instance, mortality appeared to be species
specific, but some diseases may pass from species to species. Possibly, an
abundant species like the gizzard shad can influence the incidence of disease
among sympatric species of larvae when their densities are high.
Predation on fish larvae by older fish may not be species specific. The
density and size of the prey may be more important than species differences
(Kenaga and Cole, 1975). If feeding on larvae of certain size is mostly con-
trolled by the density of larvae, regardless of species, then the dynamics of
the abundant species could influence the loss to predation among rarer species.
Food studies conducted by Price (1963) and Kenaga and Cole (1976) indicate
that the young of many fish species forage on a relatively few zooplanktonic
and zoobenthic species. The size of food eaten by most of the fish species
investigated, appears to increase as the fish grow larger. Therefore, com-
petition for food may be minimized among larvae of different sizes, but intense
among larvae of similar sizes. A species like the gizzard shad, which is
widely distributed, abundant and spawns during a long time period, is a con-
tinual potential source of competition for larvae of all sizes. If such com-
petition is important and larger proportions of clupeid larvae are killed by
entrainment, then power plant operation could conceivably foster higher sur-
vival of more desirable species, such as yellow perch, smelt and white bass.
These data, with that of Cole (1976a), imply that relatively high proportions
of clupeids are entrained and killed at the Monroe Power Plant, but uninves-
tigated competitive interactions among larvae allow only speculations of the
effect of clupeid reductions on the survival of other species.
35
-------
REFERENCES
Cole, R. A. 1976a. Entrainment at a once-through cooling system on western
Lake Erie. Report to the U.S.E.P.A. Manuscript.
Cole, R. A. 1976b. The impact of thermal discharge from the Monroe Power
Plant on the aquatic community in western Lake Erie. Technical Report
No. 32.6, Institute of Water Research, Michigan State University, East
Lansing, Michigan. 571 pp.
Denison, P. J. and F. C. Elder. 1970. Thermal inputs to the Great Lakes 1968-
2000. Internat. Assoc. Great Lakes Res. Proc. 13th Conf. Great Lakes
Res. pp. 811-828.
Ecker, T. J. and R. A. Cole. 1976. Chloride and nitrogen concentrations
along the west shore of Lake Erie. Technical Report No. 32.8, Institute
of Water Research, Michigan State University, East Lansing, Michigan.
132 pp.
Great Lakes Basin Commission. 1975a. Economic and Demographic Studies.
Appendix 19. Great Lakes Basin Framework Study. Great Lakes Basin
Commission, Ann Arbor, Michigan. 214 pp.
Great Lakes Basin Commission. 1975b. Power. Appendix 10. Great Lakes Basin
Framework Study. Great Lakes Basin Commission, Ann Arbor, Michigan.
169 pp.
Great Lakes Basin Commission. 1975c. Fish. Appendix 8. Great Lakes Basin
Framework Study. Great Lakes Basin Commission, Ann Arbor, Michigan.
290 pp.
Jensen, A. L. 1974. The effect of increased mortality on the young in a
population of brook trout, a theoretical analysis. Trans. Amer. Fish.
soc. 100(3):456-459.
Kelley, J. E. and R. A. Cole. 1976. The distribution and abundance of ben-
thic macroinvertebrates along the western shore of Lake Erie. Techni-
cal Report No. 32.7. Institute of Water Research, Michigan State
University, East Lansing, Michigan. 77 pp.
Kenaga, D. E. and R. A. Cole. 1975. Food selection and feeding relationships
of yellow perch Perca flavescans (Mitchell), white bass Morone chrysops
(Rafinesque) and goldfish Carassius auratus (Linneaus) in western Lake
Erie. Technical Report No. 32.5, Institute of Water Research, Michigan
State University, East Lansing, Michigan. 50 pp.
36
-------
Kovacik, T. L. 1972. Information on the velocity and flow pattern of Detroit
River water in western Lake Erie revealed by an accidental salt spill.
Ohio J. Sci. 72(3):81-86.
Lavis, D. S. and R. A. Cole. 1976. Distribution of fish populations near a
thermal discharge into western Lake Erie. Technical Report No. 32.9,
Institute of Water Research, Michigan State University, East Lansing,
Michigan. 61 pp.
Marcy, B. C., Jr. 1971. Survival of young fish in the discharge canal of a
nuclear power plant. J. Fish. Res. Bd. Can. 28:1057-1060.
Marcy, B. C., Jr. 1973. Vulnerability and survival of young Connecticut River
fish entrained at a nuclear power plant. J. Fish. Res. Bd. Can. 30(8):
1195-1203.
Marcy, B. C., Jr. 1976. Planktonic fish eggs and larvae of the lower Con*-
necticut River and the effect of the Connecticut Yankee Plant including
entrainment. In The Connecticut River Ecological Study; The impact of
a thermal power plant. D. Merriman and L. M. Thorpe, eds. Monograph
No. 1. American Fisheries Society, Washington, D. C. pp. 115-140.
Massengill, R. R. 1976. Entrainment of zooplankton at the Connecticut Yankee
Plant. In The Connecticut River Ecological Study; the impact of a
nuclear power plant. D. Merriman and L. M. Thorpe, eds. Monograph
No. 1. American Fisheries Society,, Washington, D. C. pp. 55-59.
McNaught, D. C. 1972. The potential effects of condenser passage on the
entrained zooplankton at Zion Station. In Review of Recent Technical
Information Concerning the Adverse Effects at Once-through Cooling on
Lake Michigan. Prepared for the Lake Michigan Enforcement Conference,
Sept. 19-21, 1972, Chicago, 111. Thomas A. Edsall and Thomas C. Yocum.
Nelson, D. and R. A. Cole. 1975. The distribution and abundance of larval
fishes along the western shore of Lake Erie at Monroe, Michigan. Tech-
nical Report No. 32.4. Institute of Water Research, Michigan State
University, East Lansing, Michigan. 66 pp.
Price, J. W. 1963. A study of the food habits of some Lake Erie fish. Ohio
Biol. Surv. Bull. 2(1):89.
Scott, W. B. and E. J. Grossman. 1973. Freshwater Fishes of Canada. Fish-
eries Res. Bd. Can., Bull. 184, Ottawa. 966 pp.
Trautman, M. B. 1957. The Fishes of Ohio. Ohio State Univ. Press. Columbus,
Ohio. 683 pp.
Vanucci, M. 1968. Loss of organisms through the meshes. Monogr. Oceanogr.
Methodol. 2:77-86.
37
-------
Walters, L. V., Jr., C. E. Herdendorf, L. J. Charlesworth, Jr., H. K. Anders,
W. B. Jackson, E. J. Skoch, D. K. Webb, T. L. Kovacik, and C. S. Sikes.
1972. Mercury contamination and its relation to other physico-chemical
parameters in the western basin of Lake Erie. Univ. Michigan Great
Lakes Res. Div. Proc. 15th Conf. on Great Lakes Res. pp. 306-316.
38
-------
APPENDIX
TABLE A-l. DISTRIBUTION OF LARVAL FISH, MIDGES AND LEPTODORA KINDTII ALONG NIGHT-SAMPLING TRANSECTS
April 1976
CO
V0
Stations
Transect A
Yellow perch
U-26
U-28
Mean
Smelt
Jt-26
U-28
Mean
Clupeid
U-26
U-28
Mean
Walleye
U-26
U-28
Mean
Sucker
U-26
U-28
Mean
Transect C
Yellow perch
U-26
U-28
Mean
Smelt
U-26
U-28
Mean
1
3.7
11.7
7-7
0.9
0.9
0.9
0.9
0
0.5
0
0
0
0
0
0
5.0
26.1
15-1
0
0
0
2
3.3
0
1.7
0
1.9
1.0
1.1
0
0.6
0
0
0
0
1.1
0.5
6.9
130.1
70.0
0
2.2
1.1
3
1.7
5-0
3.U
0
0
0
0
1.0
0.5
0
0
0
0
0
0
"
0.9
11-5
6.2
0
1.0
0.5
U
1.0
1.0
1.0
1.9
1.9
1.9
0
0
0
0
0
0
0
0
0
0
8.0
U.o
0
2.0
1.0
5
1.0
0
0.5
1.0
1.8
l.U
0
0
0
0
0
0
1.0
1.8
l.U
0
2.1
0.6
0
1.1
0.6
6
U.l
0
2.1
0.8
2.1
l.U
0.8
0
o.u
0.8
0
O.U
0
0
0
0
0
0
0
0
0
7
1.0
0.9
1.0
0
0
0
0
0
0
0.8
0
o.u
0
0
0
0
0
0
0
1.1
0.6
8
0
1.1
0.6
0
1.1
0.6
0
0
0
0
0
0
0
0
0
0
1.0
0.5
1.0
3.0
2.0
9
0
0.9
0.5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2U.2
12.1
10
0.9
0.0
0.5
1.8
2.1
2.0
0
0
0
0
0
0
0
0
0
0
1.0
0.5
0
2.0
1.0.
(continued)
-------
TABLE A-l (continued)
April 1976
Stations
56
10
Transect C
Clupeid
k-26
U-28
Mean
Walleye
k-26
U-28
Mean
Transect E
Yellow perch
U-27
U-29
Mean
Smelt
U-2T
U-29
Mean
Clupelds
H-27
U-29
Mean
Walleye
U-27
U-29
Mean
0
0
0
0
0
0
6U.2
5U.8
59.5
0.9
0
0.5
0
0
0
57.2
U.8
31.0
0 .
1.0
0.5
0
0
0
0
23.9
11.9
1.0
0
0.5
12.6
9.2
10.9
0
u.o
2.0
0
0
0
2.9
2.1
2.0
0.9
0
0.5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1.0
0.5
0
0
0
0
0
0
0
0
0
0
0
0
5.5
0
2.7
26.6
62. U
UU.5
0
2.9
1.5
1.0
0
0.5
0
0
0
0
0
0
0
0
0
0
0
0
0
1.1
0.5
0
2.1
1.1
0
0
0
0
0
0
0
U.8
2.U
0
0
0
0
2.8
l.U
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1.0
0
0-5
U.I
3.7
3.9
2.0
1.8
1.9
1.0
0
0.5
0
0
0
(continued)
-------
TABLE A-l (continued)
April 1976
Stations
Transect E
Carp goldfish
U-27
U-29
Mean
Sucker
U-27
U-29
Mean
Transect G
Yellow perch
U-27
U-29
Mean
Smelt
U-27
U-29
Mean
Carp goldfish
U-27
U-29
Mean
Clupeids
U-27
U-29
Mean
1
1.8
0
0.9
0
0
0
1U9.2
106.6
127.9
2.1
0
1.1
0
0
0
0
15.2
7.6
2
0
0
0
0
0
0
51.8
23.8
27.8
0
1.0
0.5
0
0
0
1.0
0
0.5
3
0
0
0
0.9
1.8
l.U
102.9
59-8
81. U
0
0
0
0
0
0
0
1.0
0.5
U
0
0
0
0
0
0
586.5
U3.U
31U.9
0
0
0
0
0
0
0
0
0
5
0
0
0
0
0
0
36.1
837.3
U36.7
0
0
0
0
0
0
0
0.9
0.5
6
0
0
0
0
0
0
23.6
719-5
371.6
2.U
0
1.2
0
0
0
0
0
0
7
0
0
0
0.9
0
0.5
29.0
171-7
99. U
0
0.9
0.5
0
0
0
0
0.9
0.5
8
0
0
0
0
0
0
18.6
22.2
20. U
0
0
0
0
1.7
0.8
0
0.9
0.5
9
0
0
0
0
0
0
12.9
23.5
18.2
1.7
0
0.9
0
0.8
O.U
0
0
0
10
0
0
0
0
1.0
0.5
U9.7
25.3
37.5
0
0.9
0.5
0
0
0
1.7
0
0.9
(continued)
-------
TABLE A-l (continued)
April 1976
Stations
Transect G
Sucker
l»-27
l*-29
Mean
1-2 3 U 5
0 0 0,0 16.7
0 0 0 0 5-5
0000 11.1
6789 10
0 .90 0 0
1.0 0 0 0 0
0.5 0.5 0 0 0
May 1976
hO
Transect A
Yellow perch
5-16
5-18
Mean
Smelt
5-16
5-18
Mean
Clupeids
5-16
5-18
Mean
White bass
5-16
5-18
Mean
0
0
0
0
0
0
0
60.5
30.3
0
0
0
1.9
0
1.0
1.0
0
0.5
1.9
3.0
2.5
0
0
0
0
1.0
0.5
0
0
0
1.0
0.5
0
0
0
0
0
0
0
6.0
3.0
0
0
0
0
0
0
1.0
0
0.5
1.0
1.5
1.3
1*02.7
U.U
203-6
0
0
0
1.6
3.2
1.9
3.2
2.6
0
13.5
0
2.1*
1.2
U.l
3.0
6.6
10.U
3.0
6.7
0
6.0
3.0
0
0
0
0
0
0
22.0
0
11.0
1.0
0
0-5
0
0
0
2.2
1.2
1-7
128.1
1.2
61*. 7
1.1
0
0.6
0
0
0
0
3.3
1-7
9-7
29.0
19.1*
0
0
0
0
0
0
(continued)
-------
TABLE A-l (continued)
May 1976
UJ
Stations
Transect A (cont'd)
Carp goldfish
5-16
5-18
Mean
Leptodora kindtii
5-16
5-18
Mean
Midge
5-16
5-18
Mean
Transect C
Yellow perch
5-16
5-18
Mean
Smelt
5-16
5-18
Mean
Clupeids
5-16
5-18
Mean
1
0
0
0
31*3
0
172
3
0
2
2.2
1.1
1.7
5.6
0
2.8
17.8
2.2
10.0
2
0
0
0
200
107
151*
33
51*
1*1*
0
0
0
11.0
0
5.5
20.0
1.9
11.0
3
0
0
0
60
0
30
32
0
16
0
0
0
0
.0
0
0
0
0
1*
0
0
0
52
80
66
5
180
93
0
0
0
0
0
0
0
1.5
0.8
5
3.1
0
1-5
1U8
0
71*
9
0
5
0
0
0
0
0
0
0
U.U
2.2
6
0
0
0
1*0
0
20
1*
0
2
3.2
0
1.6
6.7
0
3.1*
0
0
0
7
0
0
0
198
60
129
13
60
37
0
3.0
1.5
0
0
0
0
0
0
8
0
0
0
72
1*0
56
1
60
31
1.0
16.3
8.7
k.2
1.1*
2.8
2.1
32.7
17.U
9
0
0
0
98
0
1*9
32
0
16
3.3
0
1.7
3.3
2.7
3.0
0
0
0
10
0
0
0
231*
0
117
3
0
2
15 -U
1.1
8.3
0
13.8
6.9
0
0
0
(continued)
-------
TABLE A-l (continued)
May 1976
Stations
Transect C (cont'd)
Carp goldfish
5-16
5-18
Mean
Sucker
5-16
5-18
Mean
Leptodora kindtii
5-16
5-18
Mean
Midges
5-16
5-18
Mean
Transect E
Yellow perch
5-21*
5-26
Mean
Smelt
5-21+
5-26
Mean
Clupeids
5-2U
5-26
Mean
1
0
0
0
0
0
0
U62
0
231
1
0
0.5
0
0.8
O.I*
0
0.8
0.1*
809.1*
11*33.0
1221.2
2
0
0
0
0
0
0
1278
1*27
853
7
0
1*
0
0.9
0.5
0
5.3
2.7
278.7
112.0
195. 1*
3
0
0
0
0
0
0
69
0
140
0
0
0
0
2.8
1.1*
1*68.0
0
231*. 0
2.8
1*01.9
202. 1*
It
0
0
0
0
0
0
87
300
191*
9
20
15
0
2.7
l.l*
81.7
0
1*0.8
2.9
265.U
131*. 2
5
0
0
0
0
0
0
170
707
1*39
106
1*2
7l»
1.0
0
0.5
35.6
2.8
19.2
0
68.2
3U.1
6
0
0
0
0
0
0
17
761*
391
11*5
ll*9
11*7
1.0
0
0.5
0
67.9
3U.O
18.5
15-1*
17.0
7
0
0
0
0
0
0
0 •
0
0
0
3U5
0
1.9
0
0.9
1*1*. 9
19.5
32.2
0
0
0
8
0
0
0
0
5.1*
2.7
57
51*
56
68
36
52
i*.o
4.5
1*.3
38.0
51.1
1*1*. 6
0
6.0
3.0
9
0
0
0
0
0
0
12
161*
88
37
103
0
9.7
0
M
36.7
0
18. U
1.9
0
2.0
10
3.1
0
1.6
0
0
0
19
0
10
51
0
25
2.0
3.0
2.5
0
5.9
3.0
0
0
0
(continued)
-------
TABLE A-l (continued)
May 1976
Stations
•P-
Ul
10
Transect E (cont'd)
Shiners
5-2l*
5-26
Mean
Carp-goldfish
5-2U
5-26
Mean
Freshwater drum
5-21*
5-26
Mean
Log perch
5-2l»
5-26
Mean
White bass
5-2 1*
5-26
Mean
Leptodora kindtii
5-21*
5-26
Mean
Trout perch
5-2U
5-26
Mean
0
1.7
0.9
0
1.7
0.9
0
3.3
1.7
0
0
V
229.5
88.U
159.0
2566
2 3U7
21*57
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10.0
16.6
13.3
1*262
8179
6221
1.0
0
a. 5
0
0.9
0.5
0
0.9
0.5
0
0
0
0
0
0
0
3.8
x-9
2109
2836
21*73
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
101.9
50.9
5622
3289
1*556
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1*000
11*337
9169
0
2.8
1,1*
0
0
0
0
0
0
0
0
0
0
0
0
0
9.3
1*.7
56U
3872
2218
0
0
0
0
0
0
0
0
0
0
0
0
1.0
0
0.5
0
5.6
2.8
1698
5358
3528
0
0
0
0
0
0
0
0
0
0
1.5
0.8
0
6.8
3-1*
0
0
0
1180
782
981
0
0
0
0
0
0
0
0
0
0
0
0
1.0
16.3
8.7
0
0
0
1333
885
1109
0
0
0
0
0
0
U.O
0
2.0
0
0
0
0
2.9
1.1*
0
0
0
6160
2315
1*238
0
0
0
(continued)
-------
TABLE A-l (continued)
May 1976
Stations
10
Transect E (cont'd)
Midge
5-21*
5-26
Mean
Transect G
Yellow perch
5-21*
5-26
Mean
Smelt
5-2l»
5-26
Mean
Clupeids
5-2U
5-26
Mean
Sunfish
5-21*
5-26
Mean
Shiners
5-21*
5-26
Mean
Sucker
5-2l*
5-26
Mean
622
11388
6005
29-5
3.U
8.6
63.5
0
31.8
103.1
62.1*
82.8
0
0
£
0
0.8
o.i*
0
0
0
16
11*89
753
7.3
3.1*
5.U
15-5
0
7.8
2U. 6
377.0
200.8
0
0
0
0
2.5
1.3
0
0
0
132
93
112
2.8
6.5
«».7
1.0
1.9
1.5
10.2
350.7
180.5
0
0
0
0
1.9
0.5
0
0
0
76
1019
51*8
1.8
2.6
2.2
0.9
0.9
0.9
9.1
2l*.9
17.0
0
1.7
1.3
0
2.6
1.3
0
0
0
58
227
11*3
0
1.9
1.0
1».1»
0.9
2.7
35.0
27.6
31.3-
0
0
0
0
0
0
0
0
0
211*
700
757
0
1.0
0.5
0
0
0
9-7
10.0
9.8
0
0
0
0
0
0
0
0
0
611
521
566
0
0
0
0.9
0
0.5
9.9
25.0
17.1*
0
0
0
0
0
0
0
0
0
1180
922
1051
5.7
0
2.9
0
0
0
1.0
10.8
5.9
0
0
0
1.0
0
0.5
5-7
0.8
3.3
173
11*16
5l»7
3.0
1.1
2.1
0
0
0
0
8.7
l*.l*
0
0
0
0
0
0
1.0
0
0.5
60
1235
6U7
1.0
2.1
1.6
2.9
0
1.5
0
1.1
0.6
0
0
0
0
0
0
0
0
0
(continued)
-------
TABLE
A-l (continued)
May 1976
Stations
Transect G (Cont'd)
Carp- goldfish
5-2U
5-26
Mean
Trout perch
5-21*
5-26
Mean
White bass
5-21*
5-26
Mean
Midges
5-2U
5-26
Mean
Leptodora kindtii
5-2U
5-26
Mean
Transect A
Clupeids
6-11*
6-26
Mean
White bass
6-lU
6-26
Mean
1
0
0.8
O.I*
0
0
0
1*8.8
22.7
35.8
166
3271
1718
2122
2580
2351
U7.1
ll*.6
30.9
0
2.9
1.5
2
0
0
0
0
0
0
11.9
5U. 6
33.3
616
235
1*25
11956
2l*09
7183
525.3
21.1
273.2
0
0
0
3
0
0
0
0.9
0
0.5
0
8.1*
1*.2
132
631
381
10238
2560
6399
1*1.9
5U. 7
»*8.3
6.0
0
3.0
0
0
0
0
0
0
0
8
k
21*6
137
191
8770
6381
7576
June
79
33
56
0
0
0
1* 5
0
.8 0
.1* 0
0
0
0
0
.1* 0.9
.2 0.5
158
191
nk
252U
7086
1*805
1976
.1* 1*7.5'
.8 103.6
.6 289.3
0
0
0
6
0
0
0
0
0
0
1.0
0
0.5
17
108
63
691*6
9**32
8189
51.6
77-7
61*. 7
0
2.7
1.1*
7
0
0
0
0
0
0
0.9
0
0.5
0
ll*0
70
0
8883
1*1* !*2
117.5
115.1*
116.5
0
0
0
8
0
0
0
0
0
0
0
0
0
60
0
30
21*1
0
121
11*1.5
11*2.5
11*2.0
0
0
0
9
0
0
0
0
0
0
0
0
0
1*30
0
215
1*052
0
2026
1*51.2
l!*l*.7
298.0
0
0
0
10
0
0
0
0
0
0
0
0
0
591
190
390
2151*
908
1531
527.1*
101.6
311*. 5
0
0
0
(continued)
-------
.p-
00
TABLE A-l (continued)
June 1976
Stations
Transect A
Shiners
6-lU
6-26
Mean
Carp-goldfish
6-lU
6-26
Mean
Sucker
6-lU
6-26
Mean
Freshwater drum
6-lU
6-26
Mean
Yellow perch
6-lU
6-26
Mean
Smelt
6-lU
6-26
Mean
Log perch
6-lU
6-26
Mean
1
0
0
0
lU.7
0
7.U
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
151. U
15.1
83.3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
l6.U
8.2
6.0
2.7
U.U
12.0
0
6.0
0
0
0
0
0
0
0
12.0
6.0
0
0
0
k
0
5.6
2.8
6.k
19-7
13.0
0
0
0
0
5.6
2.8
0
0
0
0
0
0
0
0
0
5
0
2.7
l.U
7.3
0
3.7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6
537. U
16.1
276.8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6.9
2.7
U.8
7
33U.8
11.3
173.1
3.6
2.8
3.2
0
0
0
0
0
0
0
0
0
0
0
0
7.1
0
3.6
8
0
2U.2
12.1
0
0
0
0
0
0
0
5.*
2.7
0
0
0
10.9
0
5-5
2.9
0
1.5
9
1U.U
21*. 6
19.5
2.9
5-5
U.2
0
0
0
0
2.7
l.U
lU.U
0
7.2
0
2.9
1.5
0
2.7
1.4
10
0
0
0
15.5
2.7
9.1
0
0
0
0
2.7
l.U
12. U
0
6.2
0
0
0
0
0
0
(continued)
-------
TABLE A-l (continued)
June 1976
Transect A
Channel catfish
6-ll*
6-26
Mean
Black bass
6-11*
6-26
Mean
Leptodora kindtii
b-14
6-26
Mean
Midge
6-lU
6-26
Mean
Transect C
Clupeids
6-11*
6-26
Mean
White bass
6-11*
6-26
Mean
1
0
0
0
0
0
0
11*588
36872
25730
1176
1311*
5107
291*. 9
31*7.6
321.3
0.1
3.0
1.6
2
0
0
0
0
0
0
8073
1U996
11517
9379
362
1*872
1131.8
929.0
1030.U
8.8
0
1*.U
3
0
0
0
0
0
0
16228
31733
23981
U371
1270
2820
22U.7
959.0.
591.9
0
3.0
1.5
It
0
0
0
0
2.0
1.0
13521*
31122
22323
2921
7696
5309
92.7
161.5
127.1
0
0
0
Stations
5 6
0
0
0
2.8
0
1.1*
5771
25523
1561*7
731
1636
1181*
176.0
181*. 2
180.1
0
0
0
0
5.1*
2.7
0
0
0
5236
10212
7721*
10816
1*82
561*9
211.5
1*9.5
130.5
0
0
0
7
0
0
0
0
0
0
1923
33177
17550
10897
1351
6121*
66.U
67.2
66.8
0
0
0
8
0
0
0
0
0
0
2l+l
23315
11778
181
1*81*
333
36.1*
52.7
1*1*. 6
6.6
0
3.3
9
0
0
0
0
0
0
1*60
32517
25261*
172
21*6
209
98.0
1*2.1
70.1
3.1
0
1.6
10
0
0
0
0
0
0
71*
25020
1251*7
3983
l*8l
2232
71*. 1*
225.5
150.0
3.5
0
1.9
(continued)
-------
TABLE A-l (continued)
June 1976
Transect C
Shiners
6-lU
6-26
Mean
Carp-goldfish
6-lU
6-26
Mean
Yellow perch
6-lU
6-26
Mean
Channel cat
6-lU
6-26
Mean
Grapple
6-lU
6-26
Mean
Sunfish
6-lU
6-26
Mean
Smelt
6-lU
6-26
Mean
1
0
6.0
3.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
3.3
5.6
U.5
15. U
2.8
9.1
3.3
0
1.7
0
0
0
0
0
0
0
0
0
0
0
0
3
28. U
6.0
17.2
0
3.0
1.5
0
0
0
0
9.0
1».5
0
0
0
0
0
0
0
0
0
It
0
0
0
36.5
2.7
19.6
'
0
0
0
0
0
0
0
2.7
l.lt
0
0
0
0
2.7
.1.1*
Stations
5 5"
0
3
1.5
0
0
0
0
0
0
0
0
0
0
0
0
0
3.0
1.5
0
0
0
0
5.8
2.9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7
0
5.9
2.8
0
0 '
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
8
575.1
2.9
289.0
0
2.9
1.5
0
0
0
0
0
0
0
0
0
1U.6
0
7.3
10.9
0
5-5
9
288.0
3.1
1^5.6
39.8
3.1
21.5
0
0
0
0
0
0
0
0
0
0
0
0
0
3.1
1.6
10
510. U
2-9
256.7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2.9
1.5
("continued)
-------
TABLE A-l (continued)
June 1976
Stations
Transect C
Sucker
6-11+
6-26
Mean
Freshwater drum
6-lU
6-26
Mean
Leptodora kindtii
6-1 i*
6-26
Mean
Midges
6-lU
6-26
Mean
Transect E
Clupeids
6-21a
6-21b
Mean
White bass
6-21a
6-21b
Mean
Shiners
6-21a
6-21b
Mean
1
. 0
0
0
0
15-1
7.6
0
2l*8U9
2l*8U9
0
907
907
810.6
178.3
1*91*. 5
2.8
0
I-1*
2.U
0
1.2
2
0
0
0
0
0
0
0
25230
25230
0
2983
2983
52.2
_
52.2
0
_
0
0
_
0
3
0
0
0
0
0
0
682
20165
101+21*
2901
1*1*8
1675
36. I*
-
36.U
2.6
_
1.3
. 2.6
_
1.3
1*
0
0
0
0
2.7
1.1*
21+1*9
191+65
10957
0
161*
82
59.U
—
59. U
0
_
0
0
_
0
5
0
0
0
3.0
3.0
3-0
11*022
3l*0l*6
21+031*
298
267
283
73.8
156.7
115-3
2.8
0
1.1+
0
0
0
6
0
0
0
0
2.8
1.1+
18233
30198
21+215
71+05
5237
6321
68.3
-
68.3
0
-
0
5-5
_
2.8
7
0
0
0
0
0
0
18617
33025
25C21
399
708
55U
27.0
-
27.0
0
-
0
26.1
-
13.0
8
3.6
0
0
0
0
0
7791+
25807
16800
131
527
329
93.3
76.1*
8U. 9
0
2.5
1.3
0
76.1*
38.2
9
0
0
0
0
0
0
8103
29960
19031
3713
832
2273
16.0
18.1+
17.2
0
0
0
1*3.1
0
21.6
10
0
0
0
0
0
0
293
36555
181+21*
1318
11+06
1362
1*1.0
38.1*
39.7
0
0
0
12.0
7.7
8.9
(continued)
-------
TABLE A-l (continued)
June 1976
Transect E
Carp-goldfish
6-21a
6-21b
Mean
Smelt
6-21-a
6-21-b
Mean
Trout perch
u, 6-21-a
ro 6-21-b
Mean
Freshwater drum
6-21a
6-21b
Mean
Sucker
6-21a
6-21b
Mean
Leptodora kindtii
6-21a
6-21b
Mean
Midge
6-21a
6-21b
Mean
1
2.1*
0
1.2
0
0
0
0
0
0
2.8
0
l.U
0
0
0
68625
81780
75202
28U
1953
1118
2
0
_
0
8.2
-
8.2
0
0
0
2.8
-
l.U
0
0
0
13691
13691
0
0
3
0
_
0
18.2
•H
18.2
0
0
0
0
-
0
2.6
0
0
11612
11612
U520
14520
!*
0
_
0
13.7
—
13.7
2.3
It
0
- '
0
0
0
0
221149
221 U9
381*0
38UO
Stations
5 6
0
0
0
0
lfc.0
7.0
0
0
0
0
0
b
0
0
0
26150
290lt6
27598
3U1
1679
1010
0
0
5-5
5-5
0
0
0
0
0
0
0
0
31*098
3U098
328
328
7
0
0
7'. 8
7.8
0
0
0
0
0
0
0
0
1*6367
1*6367
1723
1723
8
0
0
0
0
2.5
1.3
0
0
0
0
0
0
o
0
0
95813
1*7805
71809
790
711
750
9
0
0
0
9.6
5-3
7.0
o
0
0
2.14
0
1.2
o
0
0
17819
27788
22801*
1918
2212
2065
10
o
0
0
0
2.6
1.3
o
0
0
o
0
0
o
0
0
16560
2121*8
18901*
10890
307
5598
(continued)
-------
(Jl
TABLE A-l (continued)
June 1976
Stations
Transect G
Clupeids
6-21a
6-21b
Mean
White bass
6-21a
6-21b
Mean
Shiners
6-21a
6-21b
Mean
Carp- goldfish
6-21a
6-21b
Mean
Sucker
6-21a
6-21b
Mean
Smelt
6-21a
6-21b
Mean
Yellow perch
6-21a
6-21b
Mean
1
UU8.2
276.1
2.8
11.0
6.9
0
8.2
l*.l
llt.O
0
7.0
0
0
0
0
2.8
l.U
0
0
0
2
966.9
U38.1
702.5
0
2.6
1.3
5.1
7.8
6.5
0
0
0
0
0
0
0
0
0
0
0
0
3
180.3
1218.9
699-6
5-U
2.6
U.O
19-1
13.3
16.2
5.U
8.0
6.7
0
0
0
0
0
0
0
0
0
b
U76.5
68U.1
580.3
0
0
0
7.6
19.1
13. U
0
2.7
l.U
0
0
0
0
0
0
0
0
0
5
179-6
310.8
2U5.2
0
0
0
5.U
5.6
5.5
0
5.6
2.8
0
0
0
0
0
0
0
0
0
6
UOl.O
U36.8
Ul8.9
0
0
0
1.6
0
0.8
8.0
0
U.O
0
0
0
0
0
0
0
0
0
7
102.8
163. U
133.1
0
0
0
12. U
0
6.2
12. U
U.9
8.7
0
0
0
0
0
0
0
0
0
8
521.9
299-5
U06.2
0
10.8
5-U
0
0
0
0
0
0
0
2.6
1.3
0
0
0
0
0
0
9
21*5.7
5U9.8
397.8
11.9
0
6.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10
37U.O
13U1.7
857.9
25-0
1.0
13.0
3.1
0
1.6
0
0
0
0
0
0
0
0
0
0
2.0
1.0
(continued)
-------
TABLE A-l (continued)
June 1976
Transect 0
Freshwater drum
6-21a
6-21b
Mean
Leptodora kindtii
6-21a
6-21b
Mean
Midges
6-21a
6-21b
Mean
1
0
2.8
1.1*
27901*
1*1118
31*511
51
330
191
2
0
2.6
1.3
1*9835
35972
1*2901*
2380
121*1+
1812
3
2.7
0
1.1*
26068
61931
1*3999
5 Us
h 1 |i
1*80
I*
0
0
0
50169
81*568
67369
61
33
1*7
Stations
5 6
0
0
0
69827
58563
61*195
291*
202
21*8
1.6
0
0.8
35381*
7111*3
2826U
1*88
ll*3l*
961
7
2.5
0
1.3
71893
30769
51331
297
37
167
8
0
0
0
7267
5730
61*99
586
888
737
9
0
0
0
22159
18257
20208
3012
893
2321
10
0
0
0
11U01
1*257
7879
821*
31660
16252
-------
Ul
Ul
TABLE A-2. THE CAPTURE/100 M3 OF FISH LARVAE, MIDGES AND LEPTODORA KINDTII IN BOTTOM-SLED TOWS INSHORE, ON THE
BEACH AND OFFSHORE IN WESTERN LAKE ERIE
YELLOW PERCH
April
Station
A
B
C
D
E
Mean
Date
U/27
U/29
U/27
U/29
J»/27
l»/29
l»/27
>*/29
U/27
V29
V27
W29
Inshore
0.0
1.0
35-0
26.2
8.0
2.8
3.0
0.0
196. U
21. k
U8.5
11.5
Beach
27.2
20.9
15.2
36.9
17.2
11.9
0.0
3.0
59.6
19.8
23.9
18.5
Offshore
27.0
8.6
0.0
1.1
16.2
3.6
9.6
21.0
36.9
8.7
17.9
8.6
Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
Inshore
0.0
2.6
1.3
0.0
0.0
2.0
0.0
1.0
1.0
1.1
0.5
1.3
May
Beach
1.0
3.0
0.0
U.O
3.0
1.0
-
1.0
0.0
1.0
1.0
2.0
Offshore
0.
0.
0.
5-
1.
3.
1.
12.
0.
k.
0.
U.
0
0
0
3
0
0
0
0
0
0
U
9
June
Date Inshore Beach
6/15
6/17
6/15 - 2.5
6/17
6/15 - 2.6
6/17
6/15
6/17
6/15
6/17
6/15 0.0 1.0
6/17 o.o o.o
Offshore
-
-
-
-
_
-
-
-
-
-
0.0
0.0
Grand
Mean 30.0 21.2 13.3 0.9 1.1 2.6 0.0 0.5 0.0
(continued)
-------
Ul
o>
TABLE A-2 (continued)
CLUPEIDS
Station
A
B
C
D
E
Mean
Grand
Mean
- Date
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
;
. Inshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Ipril
Beach
0.0
0.0
0.0
0.0
1.1
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.1
Offshore
0.0
0.0
0.0
0.0
0.0
2.7
5-8
3.0
1.9
0.0
1.5
1.1
1.3
Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
Inshore
2.5
30.7
5.0
58.6
87.0
703.0
7.3
60.0
1*9.0
66.5
30.1
183.0
106.9
May
Beach
168.0
9-1
0.0
5.0
0.0
7.0
-
6.0
5-8
31
3U.8
11.7
23.2
Offshore
1.0
0.0
2.0
15.8
2.0
12.0
0.0
15.0
0.0
3.0
1.0
9.1
5.1
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
Inshore
21.1
219.1
UU88.8
50U0.9
U85.7
1032.0
81.2
13.2
158.1
92.0
10U6.&
1279. U
1163.2
June
Beach
315.8
U7U.5
U12.U
79.9
88. U
217.9
63.2
23.8
121.8
109.9
200.3
181.2
190.8
Offshore
22.0
5.2
0.0
5.3
9.0
28.2
25.3
79.3
15.9
77.2
1U.U
39-0
26.7
(continued)
-------
TABLE A-2 (continued)
SMELT
April
Station
A
B
C
D
£
Mean
Grand
Mean
Date
U/27
U/29
V27
U/29
V27
i*/29
«»/27
U/29
V27
U/29
l»/27
V29
Inshore
0.0
0.0
1.2
0.0
0.0
0.0
0.0
0.0
1.9
0.0
0.6
0.0
0.3
Beach
0.0
0.0
3.3
0.0
3.2
0.0
1.0
3.0
0.0
0.0
1.5
0.6
1.1
Offshore
0.0
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
1.09
0.20
0.22
0.21
Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/1-8
May
Inshore
0.0
5-1
0.0
19.5
0.0
0.0
1.5
0.0
0.0
0.0
0.3
M
2.6
Beach
0.0
0.0
0.0
0.0
0.0
0.0
-
0.0
6.0
1.0
1.2
0.2
0.7
Offshore
0.0
0.0
2.0
0.0
1.0
3.0
1.0
6.0
7.9
28.0
2.fc
7.»*
U.9
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
June
Inshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Beach
0.0
0.0
0.0
0.0
0.0
0.0
2.8
0.0
0.0
0.0
0.6
0.0
0.3
Offshore,
0.0
0.0
0.0
5.3
0.0
0.0
2.8
0.0
0.0
8.0
0.6
2-7
1.6
(continued)
-------
Ln
00
TABLE A-2 (continued)
CARP-GOLDFISH
Station
A
B
C
D
£
Mean
Grand
Mean
Date
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
April
Inshore Beach Offshore Date
- 5/17
5/18
5/17
5/18
5/17
- ' - - 5/18
5/17
5/18
5/17
5/18
5/17
5/18
.
Kay
Inshore
0.0
0.0
0.0
2.U
0.0
0.0
0.0
1.0
3.0
2.2
0.6
1.1
0.8
Beach
0.0
0.0
0.0
0.0
0.0
0.0
-
0.0
0.0
0.0
0.0
0.0
0.0
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
June
Inshore
0.0
7.3
U3.3
21.7
11.6
0.0
8.7
2.6
95.3
0.0
31.8
6.3
19.0
Beach
50.7
0.0
2.5
0.0
65-0
0.0
0.0
0.0
0.0
0.0
23.6
0.0
11.8
Offshore
0.0
0.0
0,0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
(continued)
-------
Ui
VO
TABLE A-2 (continued)
WHITE BASS
Station Date
A It/27
It/29
B U/27
U/29
C U/27
V29
D U/27
It/29
E It/27
U/29
Mean U/27
U/29
April
Inshore Beach Offshore Date
- 5/17
5/18
5/17
5/18
5/17
5/18
1.0 - - 5/17
5/18
5/17
5/18
0.2 0.0 0.0 5/17
0.0 0.0 0.0 5/18
I
Inshore
0.0
2.5
0.0
0.0
.0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.5
toy
Beach
0.0
1.0
0.0
0.0
0.0
0.0
-
0.0
0.0
0.0
0.0
0.2
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Date
6/15
6/12
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
J\
Inshore
0.0
9.7
0.0
0.0
0.0
11.6
52.2
2.6
21.1
37.9
1U.7
12.3
.me
Beach
0.0
0.0
lit. 8
0.0
10.lt
0.0
5.5
5.3
0.0
0.0
6.1
l.l
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Grand.
Mean 0.1 0.0 0.0 0.2 0.1 0.0 13.lt 3.6 0.0
(continued)
-------
TABLE A-2 (continued)
NOTROPIS SP
Station Date
A It/27
*»/29
B l»/27
V29
C U/27
V29
o
D U/27
V29
E V27
V29
Mean V27
V29
Grand
Mean
April
Inshore Beach Offshore Date
5/17
5/18
5/17
5/18
1.0 5/17
5/18
5/17
5/18
5/17
5/18
0.0 0.0 0.2 5/17
0.0 0.0 0.0 5/18
0.0 0.0 0.1
May
Inshore
2.5
0.0
0.0
2.U
0.0
0.0
0.0
0.0
0.0
0.0
0.5
0.5
0.5
Beach
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.20
0.0
0.1
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
Inshore
16.9
0.0
16.2
16.3
0.0
0.0
2.9
0.0
0.0
0.0
7.2
3.3
5.2
June
Beach
105-3
0.0
0.0
0.0
0.0
2.7
0.0
0.0
0.0
0.0
21.1
0.5
10.8
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
(continued)
-------
TABLE A-2 (continued)
DRUM
Station
A
B
C
D
E
Mean
Grand
Mean
Date
fc/27
V29
fc/27
U/29
V27
V29
V27
V29
U/27
U/29
V27
U/29
April May
Inshore Beach Offshore Date Inshore Beach Offshore
5/17 -
5/18 ...
5/17 -
5/18 -
- 5/17 -
5/18 -
5/17 ...
5/18 ...
- 5/17 - - 1.U
5/18 ...
- 5/17 0.0 0.0 0.3
- 5/18 0.0 0.0 0.0
- 0.0 0.0 0.1
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
<]
Inshore
0.0
0.0
0.0
0.0
2.9
0.0
0.0
0.0
3.5
2.7
1.3
0.5
0.9
rune
Beach
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.7
0.0
0.5
0.3
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.6
0.0
5.3
0.0
1.6
0.8
(continued)
-------
NJ
TABLE A-2 (continued)
SUNFISH
Station
A
B
C
D
E
Mean
Grand
Mean
April
Date Inshore Beach
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
U/27
U/29
Offshore Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/L8
May
Inshore Beach Offshore Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
June
Inshore
0.0
12.1
0.0
0.0
0.0
0.0
0.0
0.0
iu.o
5.U
2.8
3.5
3.2
Beach
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.8
0.0
0.6
0.0
0.3
Offshore
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.2
0.0
0.6
0.0
0.3
(continued)
-------
ON
U)
TABLE A-2 (continued)
LEPTODORA KINDTII
April
Station
A
B
C
D
E
Mean
Grand
Mean
Date Inshore
It/27
U/29
l*/27
l*/29
l»/27
U/29
U/27
l*/29
*»/27
U/29
V27
V29
Beach Offshore Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/1-6
Inshore
67.0
728.0
1*1*0.0
0.0
20.0
0.0
0.0
682.0
0.0
1480.0
105- J*
378.0
21*1.7
May
Beach
3702,0
2065.0
1000 . 0
1*70,0
180 .'0
0.0
0.0
3231.0
0.0
672.0
976.1*
1287.6
1132.0
Offshore
5507.0
262.0
800.0
58.0
1000-0
53-0
3120.0
31MD.O
6760.0
21*91.0
31*37.1*
1200 . 8
2319.1
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6.17
June
Inshore Beach
0.
1235.
12833-
23502.
260.
5H7.
31*09.
10126.
1*530.
2582.
1*206.
8512.
6359.
0
0
0
0
0
0
0
0
0
0
1*
1*
1*
817.
1070.
9260.
31*2.
312.
1226.
808.
396.
6031.
5872.
3l*U5.
1781.
2613.
0
0
0
0
0
0
0
0
0
0
6
2
1*
Offshore
6033.0
310.0
5772.0
2995-0
1681.0
3510.0
3612.0
1*917.0
2292.0
5668.0
3878.0
3^80.0
3679.0
(continued)
-------
TABLE A-2 (continued)
MIDGE
Station
A
B
C
D
E
Mean
Grand
Mean
Date
U/27
l»/29
b/27
V29
U/27
V29
U/27
fc/29
U/27
V29
V27
V29
April
Inshore . Beach Offshore Date
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
5/17
5/18
Inshore
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.0
0.0
0.6
0.3
May
Beach
0.0
1.0
0.0
0.0
3.0
0.0
0.0
0.0
0.0
1.0
0.2
o.u
0.3
Offshore
0.0
2.0
0.0.
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.6
0.3
Date
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
6/15
6/17
Inshore
0.0
0.0
325-0
163.0
0.0
82.0
0.0
79.0
211.0
16.0
107.2
68.0
87.6
Tune
Beach
585.0
658.0
370.0
86.0
78.0
82.0
0.0
0.0
85.0
0.0
223.6
165.2
191*-1*
Offshore
83.0
0.0
0.0
103-.0
0.0
0.0
135.0
79.0
0.0
0.0
1*3.6
36.1*
uo.o
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-78-069
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Larval Fish Distributions in Southwestern Lake Erie
Near the Monroe Power Plant
5. REPORT DATE
July 1978 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Richard A. Cole
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Institute of Water Research
Dept. of Fisheries and Wildlife
Michigan State University
East Lansing, Michigan 48824
10. PROGRAM ELEMENT NO.
1BA608
11. CONTRACT/GRANT NO.
R804517010
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
13. TYPE OF REPORT AND PERIOD COVERED
4/1/76 - 4/1/78
14. SPONSORING AGENCY CODE
EPA/600/03
15. SUPPLEMENTARY NOTES
Project Officer: Nelson Thomas, Lrg. Lks. Research Station, ERL. Grosse He, MI
48138
16. ABSTRACT
This paper presents and discusses studies of larval fish distribution near
a large power plant on western Lake Erie using methods that attempt to account
for the confounding effect of environmental variation on technique effective-
ness. Distributions in the coastal zone were sampled with daytime and night-
time tows of 1-m plankton nets. Density and mortality were also sampled in the
cooling system of the Monroe Power Plant. It is concluded that prolarvae were
concentrated in specific areas near spawning sites, but larvae that reached
the lake proper are rapidly dispersed by currents. Although flooded tributaries
may act as important concentration points for certain species, no concentration
gradients persisted in the lake proper. Certain species,of larvae seemed to be
more vulnerable to entrainment than others: gizzard shad were more vulnerable
than yellow perch, white bass, rainbow smelt, shiners (Notropis) carp and gold-
fish.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Fishes
Electric Power Generation
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Fish Larvae Entrainment
Western Lake Erie
06 F
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
None
21. NO. OF PAGES
73
20. SECURITY CLASS (Thispage)
None
22. PRICE
EPA Form 2220-1 (9-73)
65
ft U.S. SOVBMKBIT HWnHIG OFFICE, 19W-7 5 7 -140 /1417
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