v THE D!STRlBUTION AND. ABUNDANCE 0F LARVAL FISHES ALONG THE ' WESTERN SHORE OF LAKE ERIE AT MONROE. MICHIGAN - Thesis for the Degree of M. S. MlCHlGAN STATE UNIVERSITY DON DAVID NELSON 1975 thfilfli .ll Lulu"; llljfljfljllll 41m in M II?” MI! 1m any n ‘- H... _--- “£-_. 5. . " ' 35 Micimfm 3mm t.,;.. .- ' ’ Q} L..utmzr.=.2ty 3, .1. “1 LIBR‘ RY " F ‘ 2: BINDING BY ~ : . HDAE & SBNS' .99!.!'.'!QEBXJ!E- ABSTRACT if THE DISTRIBUTION AND ABUNDANCE OF LARVAL FISHES J ALONG THE WESTERN SHORE OF LAKE ERIE AT MONROE, MICHIGAN BY Don D. Nelson The distribution and abundance of larval fish in and around the condenser cooling-water system of an electric generating station on western Lake Erie was studied during the summers of 1973 and 1974. Samples were collected with a l-m, #0 mesh (0.571 mm) plankton net. Analysis of variance and Tukey's post-hoc comparison were used to analyze differences in numbers of individuals collected. During the study period, 20 species or taxonomic groups were identified, although 90% of the total catch was represented by only 4 taxa. Abundances from year to year within these most abundant groups varied greatly, indicating a need for more than short-term studies. Recruitment of larvae within the discharge canal prevented a determination of entrainment losses, however, a drop in abundance between two discharge canal stations indicated that mortality may have occurred. Heated water within the discharge canal appeared to lengthen the spawning period of several less desirable species, while reducing or not affecting that of the more valuable sport species. Based on fecundity techniques, the number of larval fish entrained was estimated to be from 1 to 10% of the total Don D. Nelson available larvae, at a hatching success of 100 to 10 percent, respectively. THE DISTRIBUTION AND ABUNDANCE OF LARVAL FISHES ALONG THE WESTERN SHORE OF LAKE ERIE AT MONROE , MICHIGAN BY Don David Nelson A THESIS Submitted to Michigan State University in partial fulfillment Of the requirements for the degree of MASTER OF SCIENCE Department of Fisheries and Wildlife 1975 ACKNOWLEDGEMENTS I extend my sincere appreciation to all the people who helped in the completion of this research: Dr. Eugene Roelofs and Dr. Richard Cole, for their guidance in the development of this manuscript; my committee members, Dr. Howard Johnson and Dr. Clifford Humphrys; Mr. Jocob Hogue, Jr., Mr. Robert Wallus, and Mr. Lawrence Kay of the Tennessee Valley Authority, for their verification of identified specimens. This study was supported by grants from the Environmental Protection Agency and the Detroit Edison Company made to the Institute of Water Research at Michigan State University. ii TABLE INTRODUCTION . . . . . . MATERIALS AND METHODS . Plant Description . Study Site . . . . Sampling . . . . . RESULTS . . . . . . . . Species Composition OF CONTENTS Gizzard Shad and Alewife . . . Yellow Perch . . carp O O I O O 0 White Bass . . . . Freshwater Drum Other Species . DISCUSSION . . . . . . . Variability . . . . Effects of Plant Operation . . Geographical Area of Possible Entrainment SUMMARY AND CONCLUSIONS LITERATURE CITED . . . . APPENDIX A . . . . . . . APPENDIX B . . . . . . . Terminology . . . . Working Key . . . . Partial Bibliog aph iii Page 14 18 20 22 22 25 25 28 33 36 38 42 48 48 50 64 Table LIST OF TABLES Total number of infrequently captured larvae per station in 1973 . . . . . . Total number of infrequently captured larvae per station in 1974 . . . . . . . Estimated number of larvae potentially entrained at a 3000 megawatt production level in 1974 O O O O O O O I O O O O O Tukey's post-hoe comparison of mean catch for yellow perch in 1974 . . . . . Tukey's post-hoe comparison of mean catch for gizzard shad and alewife in 1974 O O 0 O O O O O O O I O O O I 0 Tukey's post-hoe comparison of mean catch for carp in 1974 . . . . . . . . . Tukey's post-hoe comparison of mean catch for white bass in 1974 . . . . . . iv Page 10 12 24 42 43 45 '47 Figure LIST OF FIGURES Page A map of the study area located along the west shore of Lake Erie near Monroe, Michigan . . . . . . . . . . . 3 Surface temperatures in the Raisin River, discharge canal, and along the west shore of Lake Erie during 1973 and 1974 . . 5 Average number of gizzard shad and alewife larvae collected per sampling date at each station during 1974 . . . . . . . 15 Number of larvae collected per station at three depths during 1973 . . . . . 16 Average number of yellow perch larvae collected per sampling date at each station during 1974 . . . . . . . . . 17 Average number of carp larvae collected per sampling date at each station during 1974 O O O O . O O 0 O O O O O O O O O 19 Average number of white bass larvae collected per sampling date at each station during 1974 . . . . . . . . . 21 Sampling intensity required at various permissible errors of the final mean for three confidence intervals . . . . 27 A map of western Lake Erie at Monroe, Michigan indicating the area of possible entrainment . . . . . . . . . . . . . 35 INTRODUCTION In recent years there has been increasing interest in the study of larval fish. Field studies, such as those of Marcy (1973), Noble (1970), Faber (1967), werner (1969), and others, and highly controlled laboratory studies suggested by Coutant (1971) have increased our knowledge of icthyo- plankton dynamics. Increased cultural modification of our aquatic resources has, however, stressed the need for additional information about the aquatic ecosystem. One such example is the use of cooling water in the production of electricity. Many nonscreenable planktonic forms, includ- ing icthyOplankton, may easily be entrained, and possibly destroyed. This may alter fish populations in the receiving waters. The purpose of this research was to investigate the species composition, distribution and abundance of larval fish near the west shore areas of western Lake Erie. Data are also discussed in reference to the possible operational impact of a steam-electric generating plant utilizing once- through cooling. MATE RIALS AND METHODS Power Plant Description The power plant is operated by the Detroit Edison Company near the mouth of the Raisin River at Monroe, Michigan. At full production the facility is designed to produce 3200 megawatts and requires cooling water at the rate of 110 m3/sec. The first of four 800 megawatt units began Operating in June 1971, with completion of the fourth unit occuring in May 1974. Cooling water for the plant comes from both the river and Lake Erie. Seasonal fluctuations in river discharge influence the proportion of river water in the cooling system which can range from a high of nearly 100% in the spring to a low of 5% in the late summer. Since there are significant biological differences between the lake and the river, this seasonal variation will affect the composition of biological components moving through the system. The cooling water enters the system through a 100 m long intake canal which is located approximately one-half kilometer upstream from the mouth of the river (Figure 1). Before entering the plant the water passes through several trash collecting devices, including a traveling screen with a 1 cm diagonal opening. Inside the plant the water enters a bank of condenser tubes (I.D. of 2.54 cm) where velocities may approach 2 m/sec. Flow-time through the condenser is 2 Erie 0 LC kilometer u.u.u___1 O l973 Stations 0 l974 Stations __.J Figure l. A map of the study area located along the west shore of Lake Erie near Monroe, Michigan. 4 approximately 7 seconds, and at peak production water .temperatures may be elevated 10-12 C above ambient. The heated water then flows down a concrete conduit and enters the discharge canal which is about 150 m wide and 2000 m long. The upstream half of the discharge canal is dredged to 7 m and has an average fully operational velocity of 10 cm/sec while the downstream half of the canal is dredged to only 3-4 m and has an average velocity of approximately 20 cm/sec. Under the influence of changing winds, the plume. in the lake wanders from the shore north of the discharge mouth to the shore south of the discharge mouth, and it may be 4 km or longer. A nonscreenable, nonmobile organism may, therefore, be exposed to an elevated temperature for over 8 hours. Study Site The western end of Lake Erie is a shallow basin which is separated from other areas of the lake by a series of islands and peninsulas on the north and south shores. The surface area of the basin is 3,276 kmz, and has an average depth of only 7.3 m (Carr, 22 21., 1965). Water in the basin is usually turbid as a result of surface runoff, algal growth, and sediments suspended by wave action. Secchi disk transparencies rarely exceed 1 m in the near- shore areas (Marcus, 1972). Water temperatures on selected dates during the two years of the study are presented in Figure 2. Approximately 95% of the lake's tributary flow enters the western basin through the Detroit River (Casper, 1965). r.) 36F EL [Z DISCHARGE N UPPER RIVER I LAKE a! i§ . ’1“ L p’ ’ .‘s ill/I’lllffif’Aa ?””””18 w, I I’ I’l’g. \ FIIIIIIIA .‘Ns ’ ”””’A‘ p 7”". \ rill/’1 V“ .I”” Q 7” I’lls PI . ’l”’.’l\ I973 71’” s ’IIIIIAQ _ h p b h b 4. ho no 9. no 4. 9. ac I. .u 32- 28- wodmo_hzwo mmmmwwo ASOND J MONTH FMAMJ J m EV G .I R R A R H E E C P K mmp.A D U L r’”’.’. ‘\ \ a m - iiiiiiiii ‘3 viiifllgg ifdids riiiiiiii, “\ riiiiiiii‘ ‘\ .iiiiiii ‘5 l," §§b 7”"§ ”'1‘. flags it'll”; V‘k a'llf”’ S‘s viiiiiid §§ viiiiiiiii i\‘\‘\.\ iiiiiiii! . 8‘. 4 7 m viii!!! i iiiiiiiiiiiia \\ of! \w“ u p b b n b b b n P 3 3 2 2 2 I I mo cOHooumoNHum mmmHHmz H o H H o mmoonmmo mcHoumm nonmm 00H 0 N H o o msommEOOMHEo MHmmoonmm comma usone o o m o o msumuocmm msuonuOH anmumo Hmccmno m o H O OH mooHocHHmzpm mammuuoz HocHnm OHMHOEM mH OH mm H H mchOmODc mHmouuoz RocHsm HHmuuoom m mH n H o omoH80pmoumU muwxosm mm m n mH mmH xmonofi wsuoEmo pHmEm oEsHm OmnchmHo omumcomHo oxmucH mme HTSOH Homo: .mhmH CH coHumum mom om>HmH omusummo mHucmsvmumcH mo MODES: Hmuoa .H OHQMB ll mm .mmm msHOHQOHOHZ mmmm .mmm mHEomoa nmflmcsm A.u.:oov H OHoma 12 H v HH 0 o o o MHHmHsccm meoEom mHmmMHo much 0 o o h o o H EstuH> coHooumoNHum mmmHHmz o m o N o o o moooummo mcHouom nonmm mOH o m o m o o o msomoeoomHEo mHmmoonmm nouom usouB «N mmH o m H o o mspmuocnm msusHmuoH :mHmumo Hmccmno mH be A «H mm mm mm mooflocflumnum mHmoupoz HocHnm onumEm m mm NH m o o H msflcomesa mHmmuuoz HmcHnm HHmuuomm H m H m H H H mmcHfioumoumU mumxosm o o N v n mH m xmonofi msumfimo uHmEm mmHOcOmHo omHchmHo nm>Hm H0>Hm U m 4 HmsoH momma momma Hm30H oxmq oxmq ome .vhmH cH coHumum Rom OO>HOH omnsummo mHuGOSUOHmcH mo Honfidc Hmuoa .N mHnt 13 mm HH mm vm hm ov 0H .mmm mouwumOHOHz mmmm .mmm mHsomOH nmflmcgm x.u.coov m mHnme 14 only 5% of the total catch, although they persisted until 15 July in 1974. Based on 1974 data, larvae of this group generally were most abundant in the lake, although at a level which was generally not significantly different (a = 0.05) from the discharge stations (Figure 3). On the two dates when the abundance levels of the discharge canal stations were significantly different from each other, the lower discharge station had the greater abundance. The average number of larvae at the calculated intake station was always less than the upper discharge station, but on only one date was there a significant difference. The vertical distribution of gizzard shad and alewife sampled in 1973 is presented in Figure 4. Although there was no significant difference between the depths due to the large sampling variation, seasonal summations indicate that they were more frequently captured near bottom in the lake and at mid—depth and surface in the discharge canal. Variation between years was greatest in this group, with the percent of total catch equalling 5.6 and 49.3 in 1973 and 1974, respectively. Yellow Perch Yellow perch larvae were not captured until 10 May in either year. Although minor catches persisted until 15 July, most larvae were caught on or before 11 June (Figure 5). Yolk-sac larvae were the dominant forms on the earliest sampling date, with a gradual transition to more developed stages at later dates. Yolk-sac stages were not captured 15 mcHHmEmm mom couowHHoo om>HMH OMHBOHO can omnm OHMNNHO mo woman: mommm>¢ .van mcHHso GOHumum some um mono .m musmHm mw¢E 7.330.. 9.5—2. "530.. m 9.4.— u0¢m<4 hwom «mam: cunt: o 9.4.. < 9.4... R m<>m<4 mwxm . . . . o V .U W H W . .A :8 .6. m m V. 53 .. x cu m u \ \ —\N W \\\ {on m as. .. .. . I... . W x. w wmxh. I Wfl J W. Wk m.“ N Wu . x. xxxx .60 8 _ W W..._ m WW I... I x WW xx 0 . I N... E .1 I I . W... xx I oo v _ w... . t .H _ \\ \ \ 3 n F b _ \\ \\\ \\ CO 0 _I uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu .\ an .. xx _ _ \ \ _ _ \\ \\ _ . \ \\ — u \\ \ _I lllllllllllllllllllllllllllllllll _\ \\ _ _ xx . _ \ _ _ \\ . . x I' I I I I I I I I I I I I I I I I I I I I I I I I I I I I l I I I I \. 16 .man mcHuso mnummo mmucp um coHumum mom OODOOHHOO om>HmH mo HOQEDZ 096530 «Ba 35 830.. to a: 9.2.... 8.3 J , _ ho. .8. m .on I .9. m m 400 M. .oo m. .2. w m .00 W 86m 2.55 .8 I .8— ootogoafi 09.2.35 3.53 .825 9.2:. 9.0.. I. ION M. .8 m .0? m .om W .8 r. I .2. m Row M from 30.3» u p 3.2.3.0 385mg. .23.. .52.: x. 9.2:. 9.0... m 0. m. N n .8 w m 0 on in m oe m 960 on 092.35 09285 .23.. .23: 3.2.... 3:... m w N n w a. m m. w 52.8 I m 59.6.2: 8 m. 32:6 0 3.30.4 use 38 285 .w musmflm 17 .qan mcHHOO cOHumum comm um oumc mCHHmEmm Rom UODOOHHOO om>umH couom 3OHHO> mo RODEO: mmmuo>< 35.5% 52.. * own—15.6% #02 ”$30.. uxflrz. «530.. m mx<... E ”.453 50.. uemwumma 5%..th o m § m<>m<4 o.\n . v3... < 9:3 uqméso» R NI o 3).. K Km Kw K “3 M‘xm \‘u- - .- R R .20. - A .. w .. Km :xw , I A - om _ M a m‘ - - xx _N\m \ H“ W \ \ m‘ \ m \\\ .20” \ m m S. - mm .. \ \ \ WV 9:. .x t - - - L x . _ M w. \x x I.Om . to w. \\ \ u m. .x x .06 w. \ \ _ v x x .I IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII mC\ \\\ \\ . u m“ \\\ \ ON . m_ x x . m. \\\ \ \ om “ W-\\ \ \\\ _ IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII \x_ \\ \\\ . _ \ _ _ \\ \ _ _ xx . IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII _\ \x .m ouomHm OBBnldVO HBBWON 39V83AV 18 after 29 May in 1974 and 8 June in 1973. Only 29% of the total catch were post larvae. Yolk-sac larvae were most abundant in the lower river, but at a level not significantly different from the upper discharge station (a = 0.05). Post larvae were most abundant in the lake. Of the two discharge stations, abundance in the upper discharge canal was always greater than the lower discharge canal, and on 10 May 1974 when 71% of the total larvae were captured this difference was significant (a = 0.05). Seasonal totals for the 1973 depth distribution are presented in Figure 4. The number of larvae near the bottom is significantly less at the lake and intake stations than at the two discharge stations. Yellow perch comprised 13.3% and 19.5% of the total catch in 1973 and 1974, respectively. Carp This species represents the only instance of larval occurrence on all dates in both 1973 and 1974, although a decline in abundance did occur after 1 July 1974. Yolk-sac larvae were the most abundant developmental stage, comprising 78% of the total, and were still present in the water column on 22 August 1974. Areas of greatest larval abundance were the upper river and discharge canal (Figure 6). very few larvae were found in the lake. In 1974 the upper discharge station had the greatest abundance of larvae early in the year, with the upper river gaining in importance after 11 June. Abundance 19 .vhmH mcHnso coHumum comm um mumo mcHHmEmm mom omuomHHOO OO>HMH mumo mo RODEO: mommm>¢ .m ouomHm mom.m I. omdzqm H02 533 .352. 533 m 8:: mum—4:020 mm>_m B. m<>m<.. .50“. mung: 5%.: 092.. «5.4.. 03-50» M. \O— a w M xx ON 3 m \ m xxon N w n . awn M \\o.V mu : W ml . ROW _ W m " \\\ \\\ 3 W a _ xx \ \oo w - \. “\\ \\ \\ I. _ lllllllllllllllllllllll m.l IIIIIIIIII .. \ xx \ON AH . x _ \\\ \x w u u \\ \xx \00 O _ _ \\ \ \\ IIIIIIIIIIIIIIIIIIIIIIII _\\ \\ \\ _ IIIIIIIIIIII _ \ \ _ _ \\ \\ W _ xx xx _ "\\\ \\ _. uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu . \ _ \ \\ 20 at the upper discharge station was always greater than at the lower discharge station, and this difference was generally significant. Depth distributions for 1973 are shown in Figure 4. Significantly more larvae were found near bottom in the lower discharge canal than at other stations where larvae were present. In 1973, carp larvae comprised 24.4% of the total catch, while in 1974 the percent of catch was only 11.4. White Bass In 1974, larvae of this species were not captured until 29 May and were present until 26 July. Few larvae were collected on the sampling dates in late June and early July, giving the seasonal succession a bimodal aspect (Figure 7). In 1973, this species was collected only on the last sampling date of 15 June. Success at capturing yolk-sac larvae was very limited in both years. Post yolk-sac larvae comprised almost 99% of the total species catch. The upper discharge station generally yielded the most larvae. On three dates abundance levels of this station were greater than the lower discharge station, and on two of those dates, they were significantly greater (a = 0.05). Additionally, abundance at the upper discharge station was always greater than at the calculated intake station, and on 11 June and 26 July this difference was significant. The upper river station had the lowest abundance on all dates. The 1973 vertical distribution is presented in Figure 4. The percent of larvae present at the surface and mid-depth 21 .van manso coHumum comm um oumo mcHHmEmm mom couomHHoo om>umH mmmo muHc3 mo Hogan: wmmum>< .5 muomHm momdfoma mm>_m mwgod uxdbz "530.. m mx<4 momm<4 kmom E m<>m<.. mwxm o . _.\m .N\o . gum m W . - _..o~ \ GBBflldVO HBSWON BDVHBAV 22 combined, is significantly greater than near bottom. This is true for all stations except the intake and is most apparent in the lower discharge. White bass larvae were the most abundant species in 1973, comprising 26.5% of the total catch. In 1974, these larvae were only 8.2% of the total. Freshwater Drum No larvae of this species were captured in 1973. Sampling in 1974 resulted in catches from 11 June to 15 July, although no larvae were present in the collections made on 21 June. Yolk-sac larvae comprised over 99% of the total catch. This species was present at almost all stations with no statistical difference in abundance, perhaps because of the buoyant and planktonic nature of both the eggs and yolk-sac larvae. Early in the year the discharge canal stations tended to have the greatest number of larvae. As the season progressed, the lake stations gained in importance. The upper discharge station was always higher than the lower discharge station, although this difference was not signifi- cant. Drum larvae comprised 4.3% of the total 1974 catch. Other Species Total catch data, summarized by station and date, is presented in Tables 1 and 2 for the less abundant species. No statistical analysis was performed for these groups, because of their rarity. Earliest spawners were smelt, Osmerus mordax; suckers, Catostomidae; trout perch, Percgpsis 23 omiscomaycus; log perch, Percina caprodes; and walleye, Stizostedion vitreum, and as a group these species were more closely associated with the lake environment than elsewhere. Centrarchids did not appear in the catch until early June and generally were found in the upper river and discharge canal. Channel catfish, Ictalurus punctatus, also began appearing in June, but this species was almost exclusively restricted to the upper discharge canal. Of the two minnows commonly found, emerald shiners, Notrgpis atherinoides, were most abundant and appeared to have a very wide spacial dis- tribution. Spottail shiners, Notropis hudsonius, were more frequently captured in the discharge canal. The estimated number of larvae which may be entrained are presented in Table 3. These values are based on the estimated 1974 abundances at the upper discharge station and should be viewed with caution because of the large volume of cooling water pumped at this plant and the sample variability encountered. 24 Table 3. Estimated number of larvae potentially entrained at a 3000 megawatt production level in 1974. Millions/year 1 95% Conf. Interval Species : Mean Gizzard shad and Alewife 102.1 Carp 94.4 White bass 28.1 Yellow perch 59.6 Channel catfish 6.8 Freshwater drum 7.8 Sunfishes 1.1 Spottail Shiner 0.8 Emerald Shiner 0.3 Bass Smelt Crappie Walleye Suckers Trout perch Log perch Total larvae 398.4 IA 168.9 _<_ 255.0 | A 132.6 1 180.3 | A 95.2 _<_ 200.0 | A 83.1 1 111.5 | A 28.6 i 64.9 |A 20.3 _<_ 38.3 | A 8.6 i 19.9 | A 7.9 i 20.1 7.8 i 19.5 m 0.7 m 0.7 m 0.3 m 0.2 m 0.2 m 0.2 m 0.1 1 556.0 < 841.3 1Calculated by multiplying the mean number of larvae/m3/ sampling date (and associated confidence intervals) by the volume flow through the cooling system on that date to determine a daily estimate of entrainment. The daily estimate was assumed to represent that sampling date plus half the number of days since the previous sampling date and half the number of days to a subsequent sampling date. Each daily estimate was multiplied by the number of days that it represented and the sum of these gave the annual estimate of entrainment. DISCUSSION Variability The variability encountered in this study was a crucial sampling problem. Capture per unit effort occasionally varied by as much as a magnitude of 10 between individual replicates at the same station. Also, approximately equal sampling intensity during the two years in the same months of May and June produced total catches per year that differed by a magnitude of over 6.5. Variability between replicates may have been increased by sources of error inherent in the sampling procedures, the most important of which may have been extrusion of small larvae through the mesh, clogging of the mesh, and imperfect measurements of the amount of water filtered by the net (Aron, 33 31., 1965; Barnes and Tranter, 1965; Taylor, 1953; Winsor and Clark, 1940). Active avoidance of the net may also have contributed to sampling error and has been shown to be inversely related to net speed (Barkley, 1964). Aron and Collard (1969) demonstrated that very small changes in net speed resulted in significant changes in catch, and that even at the same engine speed, winds and currents could produce significant errors. A third major source of error is probably associated with a patchy, nonrandom spacial distribution of organisms (Roessler, 1965; Sameoto, 1975; Taylor, 1953). Wiebe (1971) 25 26 showed, with simulated net tows using a computer model, that the size and distribution of patches significantly. affects both the accuracy and precision of estimates of abundance. Wiebe and Holland (1968) summarized field estimates of total sampling error from 13 studies and found that 95% confidence limits of a single observation usually exceeded half or double the observed value (percentaged ranges) regardless of the type of net, the method used in towing, or the organisms used in the calculations. Although the 95% confidence limits in this study were large, they never approached the levels reported in other studies discussed by Wiebe and Holland (1968). It is possible that this re- duced variability was caused by the more homogeneous nature of Lake Erie. The sampling intensity required at various permissible errors of the final mean is presented in Figure 8. This technique is described by Edmonson and Winberg (1971) and values are based on an average seasonal estimate of variability pooled across stations. It is apparent that considerable sampling effort would be required when permissible errors are set very low, and desired confidence intervals are set at a high probability level. Of course, even greater sampling intensity would be required if relatively scarce forms become the target species, or a more heterogeneous system than Lake Erie is sampled. The difference between total catch in each year of the study is more difficult to explain. Faber (1967) also noted that abundance varied greatly from year to year in a three year study of two Wisconsin lakes.' Although the sampling N 0' OI N on fl REPLICATE/STA. [LOG SCALE] 6 GIZZARD SHAD and ALEWIFE 27 REPLICATE/STA. [LOG SCALE] 8 0| 1 N o .l .2 I .3 .5: PERMISSABLE ERROR Figure 8. PERMISSABLE ERROR :69 N 0| I an 5 REPLICATE/STA. [LOG SCALE] N 0| 3 .3 REPLICATE/STA. [LOG SCALE] 00 N on I YELLOW PERCH .i .2 .3 .4 PERMISSABLE ERROR WHITE BASS .5 .3 .2 .3 , .4 PERMISSABLE ERROR errors-of the final mean for three confidence intervals. Sampling intensity required at various permissible 28 technique for each year in this study was different, it is improbable that this change could account for the total difference in abundance among most species. Unknown temporal variation may have contributed to the difference, but there remains the possibility that the relative abundance estimates for each year were realistic. In 1973, water levels reached a record high. Spring was marked by numerous storms and seiches, and it is possible that hatching success and larval survival was severely limited by these climatic conditions. It may well be that the most important impact of annual variability is the implication it carries for short term studies. Effects of Plant Operation Marcy (1973) reported that most of the larvae entrained in the cooling water of a power plant were dead by the time they reached the end of a 1.8 km discharge canal. Edsall and Yocom (1972) reviewed additional literature and discussed the potential harm of entrainment to larval fish. Attempts to assess mortality in this study were com- plicated by the fact that many species appeared to use the discharge canal throughout their life cycle. Abundances of adult carp, goldfish, and channel catfish were significantly higher in the discharge canal than at stations outside the canal at most times of the year (Lavis, unpublished data). While high turbidity made visual observations difficult,‘ carp were commonly seen spawning along the length of the canal. It would appear that the lower end of the canal and the Vicinity near the mouth could have provided excellent 29 spawning habitat for gizzard shad as described by Bodola (1966). Catches of channel catfish larvae were almost exclusively restricted to the upper discharge canal, although the spawning activity of this species was not observed. White bass are not year-around residents of the discharge canal, but were captured in great numbers by local fishermen during the reported spawning time. Examination of adult specimens from the canal disclosed both spent and ripe individuals. Larvae may be retained within the canal by large, quiet eddies at both ends together with the interstitial waters in the rock walls. Of all the abundant species, adult yellow perch were only rarely captured in the discharge canal (Edwards, 1973). In 1974 the majority of yellow perch yolk-sac larvae were captured on 10 May. The abundance at the calculated intake station was comparatively low, primarily because of the high river discharge rate and the low abundance levels associated with it. However, discussions with Detroit Edison personnel indicated that at this time of year large numbers of yellow perch eggs in their semi-buoyant, gelatinous strings were accumulating on all of the trash collecting devices. It is possible that the calculated abundance at the intake station was an underestimation, because of this concentration of eggs and subsequent hatching. The lower river station, which had the highest abundance, was probably more repre- sentative of the actual numbers entrained. The abundance at the upper discharge station was not significantly different from that at the lower river station, but the lower discharge 3O canal station had significantly fewer larvae than the upper discharge canal station. Marcy (1973) noted that fewer dead larvae were collected as sampling approached the lower end of a discharge canal, suggesting a settling out process. If mortality is occurring, and dead larvae are being lost from the water column with no recruitment, then the abundance levels should drop. The significant difference between the upper discharge canal and the lower discharge canal most likely represented entrainment mortality, perhaps coupled with possible predation of stressed larvae. Additional confirmation is represented by the 1973 depth distribution of yellow perch. Significantly more larvae were located in the upper half of the water column at the lake and intake stations than at the discharge canal stations. In the discharge canal the majority of larvae were located near bottom. Analysis of the difference between discharge canal stations is less meaningful for other abundant species, since recruitment may be occurring in the canal. Carp and white bass, however, generally had significantly lower abun- dance levels at the lower discharge station, which may also have represented entrainment mortality. From the data, it is not possible to determine the exact percent of mortality, since no on-site examination was made to determine whether the larvae were dead or alive. Mortality studies, using techniques described by Marcy (1971), should be made to fully assess the problem. 31 The possibility exists that the heated water produced by this plant may alter the reproductive cycle for those fish that utilize the discharge canal for spawning activity. Swee and McCrimmon (1966) indicated that spawning of carp began at 17 C and ceased at 28 C. In 1974, discharge temperatures reached spawning levels as early as late March, and yolk-sac carp were captured in the discharge canal on 22 April, the first sampling date. River temperatures did not reach 17 C until late May, and in early June the dis- charge temperatures began exceeding 28 C. Probably as a result, the abundance of carp larvae at the upper river station first exceeded discharge catches on 11 June and generally remained higher than at other stations throughout the rest of the sampling period. It is possible that nearly two months may have been added to the spawning period of this species. Bodola (1966), in a study of gizzard shad in western Lake Erie, reported that spawning occurs from the first of June to the first of July at temperatures between 17 C and 23 C. The majority of yolk-sac gizzard shad were captured during this period, but in 1974 they were also found as early as 22 April within the discharge system where temperatures had already exceeded 17 C. As much as two months may also have been added to the spawning period of the gizzard shad as a result. The spawning period of the white bass was apparently not extended by the discharge temperatures. Scott and Crossman (1973) reported that this species commenced spawning when water temperatures reached 13 C. This level was attained 32 in the discharge by mid-March, but no yolk-sac larvae were Captured until late May. Prior to spawning activity, white bass are located offshore, and it is probably the tempera- ture of these waters that initiates spawning. Individuals entering the discharge canal may even experience a reduced spawning period, If onshore movement does not commence until mid-May, temperatures in the discharge canal have already reached 26 C, which is the upper spawning temperature reported by Scott and Crossman (1973). The only date when yolk-sac larvae were captured was 29 May. Channel catfish begin spawning when water temperatures reach 24 C, with an optimum Spawning temperature of 27 C (Carlander, 1969). In 1974, discharge temperatures reached this level by mid-May, while the lake was not at this tempera- ture until mid-June. Larval catfish were captured in the discharge canal as early as late May, but the first lake catch did not occur until late June. Also, in both years of the study lake temperatures never reached the Optimum spawning temperature. Since catches of catfish larvae were almost exclusively restricted to the discharge canal, it would appear that the discharge canal provides a more favorable thermal environment and spawning habitat than the lake. At least one month may be added to the spawning period of this species. The possible effect of increasing the spawning period of less desirable species, while at the same time not affecting or reducing the period of preferred sport species, is unknown. It is feasible that longer spawning periods could provide a competitive advantage. Year classes of 33 species with short spawning periods may be more vulnerable to adverse climatic conditions which severely effect hatch- ing success. As a result of subtle, long-term changes, fish populations in the receiving waters may be altered. Geographical Area of Possible Entrainment Little is known about the swimming behavior of larval fish in their natural environment. Bishai (1960) and Houde (1969) have used laboratory investigations to measure the sustained swimming speed and endurance of several species. Evidence indicated that the very early stages of pelagic larvae were carried by water currents from their spawning areas, although the movement was not entirely passive. Houde (1969) suggested that the distribution of newly hatched walleye and yellow perch is not likely to be greatly influenced by swimming ability until a total length of 9.5 mm is attained. This length generally corresponds to forma— tion of incipient caudal rays and complete absorption of the yolk material. Based on growth estimates of yellow perch by Mansueti (1964) and Luz (1960), this length would be reached on approximately the 16th day after hatching. Gizzard shad, alewife, and carp may attain this threshold as early as 7 to 10 days after hatching, because of more advanced developmental rates (Ciance, 1969; Battle, 1940; and Mansueti and Hardy, 1967). Less is known about the developmental rates of other dominant Lake Erie Species. Although information is not available on specific water currents in the area, they appear to be highly cor- related with winds. Using a surface value velocity of 2 34 percent (Hutchinson, 1957) of the monthly mean resultant wind for 1970 through 1974, a simple model of the surface area potentially influenced by the plant is shown in Figure 9. Although larvae spawned some distance away from the plant may eventually be entrained, the probabilities are much greater for those hatched in and around the plant. But, persistent storms could have a major affect on the distribu- tion of larval fishes throughout the western basin of Lake Erie. Studies describing larval abundance within the sphere of influence, designation of important nursery sites, and more precise current measurements are required to adequately evaluate the problem. Although the estimated numbers of larvae entrained at this plant were extremely large, they may not be particularly significant. Based on commercial catch records of Michigan waters (Baldwin and Saalfeld, 1970), estimates of mean individual size (Parkhurst, 1971), and estimates of fecundity (Mansueti and Hardy, 1967; Scott and Crossman, 1973), total annual entrainment may represent only 1 to 10 percent of the total available larvae at a hatching success of 100 and 10 percent, respectively. Until more is known about the dynamics of the fish populations within the area, such as survival and developmental rates, a precise evaluation of the entrainment impact on future adult populations is not possible. 35 C h . . . . . 00K..:..’:. ' “. . . OI . I 0 ’ .. .. ... o ..0 a . I... ..... o u .0. ".0 s . .. 0:20. ‘ 2: ' .l .0 Q, o . a U . (1 w~ ’% o.:. . ’ J """" -\. _' '0': . :s '.l '0‘! I .1 .5... I'} I. . '0 . .. ' e' I month Monthly Resultant Wind 2 months Figure 9. A map of western Lake Erie at Monroe, Michigan indicating the area of possible entrainment. SUMMARY AND CONCLUSIONS Estimates of abundance were significantly different between the two years of the study, based on approxi— mately equal sampling intensity. It is, therefore, possible that major inconsistencies may be observed if icthyoplankton abundances are studied for only short periods of time. The large variability among replicates observed in this study was thought to be primarily related to a patchy, nonrandom distribution. As a result, sampling may have to be intensified to detect differences among stations. 2 Several species appeared to use the discharge canal for spawning, making it difficult to assess entrainment mortality. Yellow perch, which were not believed to spawn within the discharge canal, exhibited decreased numbers as they progressed through the system. This decrease was thought to primarily represent entrained mortality. The length of the spawning period appeared to have been increased for gizzard shad, carp, and channel catfish; and possibly reduced for white bass, because of the heated water within the discharge. This may result in long-term changes in fish populations of the receiving waters, 36 37 particularly if once-through cooling is expanded in the western basin. The number of larvae which were entrained at the Monroe plant was extremely large, but perhaps ecologically insignificant. However, the re-establishment of sport fish populations may be precluded if these species require nursery areas within and near the mouth of the Raisin River. LITERATURE CITED Aron, W., E. H. Ahlstrom, B. McK. Bary, A. W. H. Be., and W. D. Clarke. 1965. Towing characteristics of plank— ton sampling gear. Limnol. Oceanog., 10(3): 333-340. Aron, W. and S. Collard. 1969. A study of the influence of net speed on catch. Limnol. Oceanog., 14(2): 242-249. Baldwin, N. S. and R. W. Saalfeld. 1970. Supplement to technical report No. 3. Commercial fish production in the Great Lakes, 1867-1960. Great Lakes Fishery Commission. Barkley, R. A. 1964. The theoretical effectiveness of towed net samplers as related to sampler size and to swimming speed of the organism. J. Conseil Conseil Perm. Intern. Explor. Mer., 29: 146-157. Barnes, H. and D. J. Tranter. 1965. A statistical exami- nation of the catches, numbers and biomass taken by three commonly used plankton nets. Aust. J. Mar. Freshwater Res., 16: 293-306. Battle, Helen I. 1940. The embryology and larval develop- ment of the goldfish (Carassius auratus L.) from Lake Erie. Ohio J. Sci., 40(2): 82-93. Bishai, H. M. 1960. The effect of water currents on the survival and distribution of fish larvae. J. Conseil Conseil Perm. Intern. Explor. Mer., 25: 134-146. Bodola, A. 1966. Life history of the gizzard shad in western Lake Erie. U. S. Fish and Wildl. Serv. Fish. Bull., 65: 391—425. Carlander, K. D. 1969. Handbook of freshwater fishery biology. Vol. 1. Life hiStory data on freshwater fishes of the United States and Canada, exclusive of the Perciformes. Iowa State Univ. Press, Ames, Iowa. 752 pp. Carr, John F. and Jarl K. Hiltunen. 1965. Changes in the bottom fauna of western Lake Erie from 1930 to 1961. Limnol. Oceanog., 10(4): 551-569. 38 39 Casper, V. L. 1965. A phytoplankton bloom in western Lake Erie. Proc. 8th Conf. Great Lakes Res., Inter. Assoc. Great Lakes Res., Ann Arbor, Michigan. Pub. No. 13: 29-35. Cianci, John M. 1969. Larval development of alewife, Alosa pseudoharengus, and the glut herring, Alosa aestIValis. Master's thesis, Univ. Conn., 62 pp. Coutant, C. G. 1971. Effects on organisms of entrainment in cooling water; steps toward predictability. Nucl. Saf., 12: 600-607. Edmondson, W. T. and G. G. Winberg. 1971. A manual on methods for the assessment of secondary productivity in freShwater. International Biological Programme No. 17, Oxford, England, 358 pp. Edsall, Thomas A. and Thomas G. Yocum. 1972. Review of recent technical information concerning the adverse effects of once-through cooling on Lake Michigan. U. S. Fish and Wildl. Serv., Great Lakes Fish Lab., Ann Arbor, Michigan. Unpublished. Edwards, Thomas J. 1973. An ecological evaluation of a thermal discharge. Part VIII: Some effects of initial Operation of Detroit Edison's Monroe power plant on fish populations of Lake Erie's western shore area. Tech. Rep. No. 32.2, Institute of Water Research, Michigan State University, East Lansing, Michigan, 60 PP- Faber, D. J. 1967. Limnetic larval fish in northern Wisconsin lakes. J. Fish. Res. Ed. Can., 24(5): 927-937. Hartley, R. P., C. E. Herdendorf, and M. Keller. 1966. Synoptic water sampling survey in the western basin of Lake Erie. Proc. Ninth Conf. Great Lakes Res., Inter. Assoc. Great Lakes Res., Ann Arbor, Michigan. Pub. No. 15: 301-322. Houde, E. D. 1969. Sustained swimming ability of larval walleyes, Stizostedion vitreum vitreum, and yellow perch, Perca flavescens. J. Fish. Res. Ed. Can. 26(6): 1647-1659. Hutchinson, G. E. 1957. A treatise on limnology. Vol I. Geography, physics, and chemistry. John Wiley and Sons, Inc., New York, N. Y. Luz, F. E. 1960. Notes on first-year growth of several species of Minnesota fish. Progr. Fish. Cult., 22: 81-820 Mansueti, Alice J. 1964. Early development of the yellow perch, Perca flavescens. Chesapeake Sci., 5(1-2): 46-66. 40 Mansueti, Alice J. and Jerry D. Hardy, Jr. 1967. Develop- ment of fishes of the Chesapeake Bay region. An atlas of egg, larval, and juvenile stages. Part I. Natural Resources Institute, Univ. Maryland, 202 pp. Marcus, Michael D. 1972. An ecological evaluation of a thermal discharge. Part II. The distribution of phytoplankton and primary productivity near the western shore of Lake Erie. Tech. Rep. No. 14, Institute of Water Research, Michigan State Univ., East Lansing, Mich., 96 pp. A Marcy, B. C. 1971. Survival of young fish in the discharge canal of a nuclear power plant. J. Fish. Res. Bd. Can., 28(7): 1057-1060. Marcy, B. C. 1973. Vulnerability and survival of young Connecticut River fish entrained at a nuclear power plant. J. Fish. Res. Bd. Can., 30(8): 1195-1203. Noble, R. L. 1970. Evaluation of the Miller high-speed sampler for sampling yellow perch and walleye fry. J. Fish. Res. Bd. Can., 27(6): 1033-1044. Parkhurst, Benjamin R. 1971. An ecological evaluation of a thermal discharge. Part V: The distribution and growth of the fish populations along the western shore of Lake Erie at Monroe, Michigan during 1970. Tech. Rep. No. 17, Institute of Water Research, Michigan State Univ., East Lansing, Mich., 71 pp. Roessler, Martin. 1965. Analysis of the variability of fish populations taken by otter trawl in Biscayne Bay, Florida. Trans. Amer. Fish. Soc., 94(4): 311-319. Sameoto, D. D. 1975. Tidal and diurnal effects on zoo- plankton sample variability in a near shore marine environment. J. Fish. Res. Bd. Can., 32(3): 347-366. Scott, W. B. and E. J. Crossman. 1973. Freshwater fishes of Canada. Fish Res. Bd. Can. Bul. 184, 966 pp. Swee, U. Boon and Hugh R. McCrimmon. 1966. Reproductive biology of the carp, Cyprinus carpio L., in Lake St. Lawrence, Ontario. Trans. Amer. Fish. Soc., 95(4): 372-380. Taylor, Clyde C. 1953. Nature of the variability in trawl catches. U. S. Fish. and Wildl. Serv., Fish. Bull., 54(83): 145-166. Werner, R. G. 1969. Ecology of limnetic bluegill (Lepomis' macrochirus) fry in Crane Lake, Indiana. Amer. Mldl. Nat., 81: 164-181. 41 Wiebe, P. H. 1971. A computer model study of zooplankton patchiness and its effect on sampling error. Limnol. Oceanogr., 16(1): 29-38. Wiebe, P. H. and W. R. Holland. 1968. Plankton patchiness and effects on repeated net tows. Limnol. Oceanogr., 13(2): 315-321. Winsor, C. P. and G. L. Clarke. 1940. A statistical study of variation in the catch of plankton nets. J. Mar. APPENDIX A 42 .omumsomfla Hm3oq n ma “mmumnomwo swam: n as umxmucH u H “Hm>am momma n m “Hm>fim H0309 n ma NU oxmq n on um oxen n ma um mxmq u ¢QN .soHumEHommamuu uoou mHMDWm an hpflmGOUOHmumn How cmuomuuoo mum wcmmzH ho>.o oom.o oom.o «NH.H mhv.m omm.m vmm.m Hmm.w cum: mg m «A DA H mm DA on cofiumum mash Ha hom.o vmm.a huh.a mmm.H mom.~ mmv.~ mmm.m Ham.m cums m mg as H mg UA mm «A coflumum >62 mm mom.m oaa.m oqa.m omo.m omm.h 5mm.m sum: m H OH mg DD ma mcowumum >62 OH .ehma CH nouwm 30HH¢> How nonmo Gama mo COmHHmmEoo oonlumom.m.mmx59 .Hld OHQMB H 4 xHozmmmfl 43 mom.m me.w mmh.v ovm.v mph.m mhm.m mmm.m mNo.h cam: m H MA mg mg OD OH OH GOHumpm HHss me hm~.m mo~.v mmm.m chm.m mn¢.o mmm.m mmm.m HMH.> cam: m «H OH mm H DD QA mu soHuMDm HHsn H hon.o mmm.H hmm.m Nmm.m hmm.m Hwb.m vmm.m mmm.¢ cum: m H mm a: <4 ma on DA .soHumum wasp Hm mwh.H vnm.m mmm.m mvh.m Ham.m vm>.m hmo.m moa.mH cum: m «A H ma OH OH DD mg coHumum mash HH H¢m.H mom.H vmv.H HHh.H oam.a omm.m mom.m mHm.w cam: ma H m as 44 OH OH mg mcoHumum >62 mm .vhmH CH mHszHm one team Uhmuuflm How coumo came mo QOmHHmmEoo ooznumom m.>mx59 .mum mHQMB fi NHQmem¢ 44 .mmumcomHQ H0309 H OH “omnmnomHn momma u OD “mxmucH u H uu0>Hm some: n m “H0>Hm Hm3oq n mg no mxmq n on “m mxmq "mg “m mxmq H «mm .coHumEHoncmuu uoon shadow HQ muflosmmOHmums How pmeowunoo mum mcmoza wmm.o mmo.H 5mm.H omm.m omm.m mmv.m onm.m mmo.¢ c602 mg H DA «A m as OH mg cOHumum Hess om 1.9.coov mum menus 45 mmm.0 mg NH0.0 000.H mg 0mm.H 050.H QQ m00.N UH 505.0 on 505.0 505.0 0mv.~ OD vm0.H mg Nmm.H DA 505.0 505.0 m0m.H UH mm5.H mg mmm.H 0H5.N mmm.m 005.m DA N50.v OD 505.0 mg 505.0 DA mam.0 UH NOH.H fig mHN.H vm5.v 5NN.v OD 5HN.5 0m¢.H 505.0 505.0 mg Hmm.0 050.0 Hmv.H mg Nmm.a DH Nm¢.N DD Hm5.m DD N cmmz coflpmum Hess cmwz aoflpmum mach cum: coHumum mach Gums coHumum HMS cmmz cofiumum 5oz Hm HH mm 0H .V5mH CH mHmo HOH H noumo cmmE Ho QOmHHmmEoo occlumom m.>mxde 4 xHQmem¢ .mt4 magma 46 .mmumnomHQ Hm3OH H OH “mmumnomfla memD u DD umxmucH u H “Hm>Hm HmmmD u m «Hm>Hm HQBOH n mH “U mxmq H OH um wme u mH “4 oxcH u «Hm .coHumSHoncmnu Doom mumsqm 5b thocmmonmumc HoH pmuowuuoo mum msmwzH 505.0 500.0 N00.H mmm.H mmm.H va.H m5m.H Hmm.m saw: «H OH mH DH mg a: H m :oHumum mHsn mH A.p.qoov mu< mHnme 47 .Hmcmu ommmsomma moBOH 0H “Hmsmu ommmnomHa momma “oxmmcH n “mo>Hm momma u m “mo>Hm moBOH mH “U oxMH H OH um oxMH n mH “0 oon n .coHumEmowwcmmm uoom ommsvm >2 hmHosomomouos mom womoommoo omo mcmoz 505.0 055.0 0H0.0 500.0 000.H H00.H H0m.m 005.0 :moz m H mH OH «H OH aa mH compoum Hmsn 505.0 500.0 000.H 000.H 000.H 000.H 000.H 005.H Goo: 0 OH 04 mH. OH H aa ma COHuoum Hmsn Hm0.0 00H.H 000.H 000.0 000.0 000.0 000.0 000.0 coo: 0 mg oxse .0I4 oHQme 4 xHazmmm< APPENDIX B APPENDIX B Identification Identification of larval fish is generally difficult, due primarily to their small size, the degree to which their form changes with development, and the lack of in- formation on many Species. Identification may be further complicated in a productive system, such as Lake Erie, because of the large number of Species that are encountered. The following key is provided as a tool to assist the in- experienced worker in this task. To the experienced re- searcher, it is designed to serve as a verification of the identifications made in this study. The terminology for the description of larval stages comes from May and Gasaway (1967). An excellent description of the meristic and morphometric characters used in this key is provided by Mansueti and Hardy (1967). The terminology given below is modified from the above sources, and is included for use if these references are not available. Pro-larva -- Larva with yolk-sac present. Early Post-larva -- Larva after complete absorption of the yolk to the development of soft rays in the vertical fins. Late Post-larva -- Larva with soft rays in the vertical fins to the full development of all fins, scales, and the lateral line canal system. 48 49 Pre-anal Length -— Distance from the tip of the snout to the posterior margin of the anus. Post-anal Length -- Distance from the posterior margin of the anus to the tip of the caudal fin or finfold. Gut Length —- Before development of the operculum, the distance from the most posterior part of the auditory vesicle to the posterior margin of the anus; follow- ing operculum formation, the distance from the most posterior part of the opercular membranes to the posterior margin of the anus. Pre-anal Myomeres -- Myomeres between the most anterior myoseptum and the posterior margin of the anus. Post-anal Myomeres -- Myomeres between the posterior margin of the anus and the most posterior myoseptum. Entire Yolk-sac -- Yolk-sac that extends along the entire gut length. 1a. lb. 2a. 2b. 3a. 3b. 4a. 4b. WORKING KEY TO THE LARVAL FISHES DISCOVERED NEAR THE WEST SHORE OF LAKE ERIE Vertical fin rays formed, or nearly so. Late post-larvae. (Note: Late post-larvae were rarely captured in this study, and are not included in this key. Although not all adult and juvenile characteristics are developed, body shape and fins begin to resemble the adult and may be used for diagnostic characters). Vertical fin rays not formed, or apparently incomplete . . . . . . . . . . . . . . . . . . . 2 Yolk-sac apparent. Pro-larvae . . . . . . . . . 3 Yolk-sac not apparent, or only vestige remain- ing Early post-larvae . . . . . . . . . . . . . 27 Barbels present, with extremely large yolk-sac . 4 Barbels absent . . . . . . . . . . . . . . . . . 5 Yolk-sac larvae probably greater than 10 mm TL. In very early stages, yolk-sac extends posterior to the vent. Caudal fin forked by at least 14.8 mm TL . . . . . . . . . . . . . . . . . . . . . . . . . . Channel catfish (Ictalurus punctatus) Yolk-sac larvae probably less than 10 mm TL. Yolk- sac never extends behind vent. Caudal fin never forked . . . . . . . . Bullheads (Ictalurus spp.) 50 5a. 5b. 6a. 6b. 7a. 7b. 8a. 8b. 51 A conspicuous adhesive organ on the snout of larvae less than 14 mm TL. Very heavily pig- mented rudimentary vertical fins present in the finfold . . . . . . . . . Gar (Lepisosteus spp.) Not as above . . . . . . . . . . . . . . . . . Post-anal length enters pre-anal length more than or equal to 3 times, and generally more than 4 times . . . . . . . . . . . . . . . . . . . . . Post-anal length enters pre-anal length less than 3 times . . . . . . . . . . . . . . . . . . Post-anal length enters pre-anal length from 4.7 to 5.8 times. Small oil globule present at posterior margin of yolk-sac. Eyes unpig- mented at less than 5 mm TL . . . . . . . . . . . . . . . . .Gizzard shad (Dorosoma cepedianum) Post-anal length enters pre-anal length from 3.3 to 4.3 times. Oil globule not present. Eyes pigmented at hatching, but only barely so . . . . . . . . . . . .Alewife (Alosa pseudoharengus) Pre-anal myomeres greater than or equal to 42. Yolk-sac small and extremely posterior, being noticeably behind pectoral fin buds. If present, ventral pigmentation in the form of a single row along the ventral margin. Post- anal length enters pre-anal length from 2.3 to 2.8 times . . . . . . . . .Smelt (Osmerus mordax) Pre-anal myomeres less than 42, and not as above 0 C O O O O O C . O . O O O O O O O O 9a. 9b. 10a. 10b. 11a. 11b. 12a. 12b. 13a. 13b. 14a. 14b. 15a. 15b. 52 Yolk-sac larvae greater than or equal to 9 mm TL . . . . . . . . . . . . . . . . . . . . . 10 Yolk-sac larvae less than 9 mm TL . . . . . . . 12 Yolk—sac entire. Post-anal length enters pre- anal length from 2.3 to 3.0 times. Pre-anal myomeres from 35 to 40 . . . . . . . . . . . . Suckers (Catostomidae); probably Catostomus com- mersoni Yolk-sac less than entire . . . . . . . . . . . 11 Pre—anal myomeres greater than or equal to 25 . Northern pike (Esox lucius) Pre-anal myomeres less than 25 . . . . . . . . . Walleye (Stizostedion vitreum). See 14a. Pre-anal myomeres greater than or equal to 29. Yolk-sac entire . . . . . Suckers (Catostomidae) (NOTE: probably Carpiodes cyprinus if TL less than 8.0 mm and pre-anal myomeres from 28-32 with heart or Y-shaped pigment pattern on dorsal head). Pre-anal myomeres less than 29 . . . . . . . . . 13 Pre-anal myomeres greater than or equal to 19. . l4 Pre-anal myomeres less than 19 . . . . . . . . . 18 Post-anal myomeres greater than or equal to 22, Post-anal length enters pre-anal length .8 to .9 times. Yolk-sac elongate with anterior oil globule . . . . . Walleye (Stizostedion vitreum) Post-anal myomeres less than 22 . . . . . . . . 15 Yolk-sac entire, with no anterior oil globule . 16 Yolk-sac less than entire, with anterior oil globule . . . . . . . . . .°. . . . . . . . . . 17 16a. 16b. 53 Post-anal length enters pre-anal length less than or equal to 1.9 times. Body slender and may be only lightly pigmented. If pigmentation present, ventral chromatophores commence at base of caudal and ex- tend anteriorly on the ventral side of the yolk-sac. Gas bladder, if present, only lightly pigmented. Few chromatophores on dorsum . . . . . . . . . . . . . . . . . Shiners (Notropis spp.). See 46b. (NOTE: Difficult to separate species. Spottail Shiners (N, hudsonius) collected from Lake Michigan and Lake Erie are pigmented as described above. Pro-larval emerald Shiners (N. atherinoides) were not collected, however, later staged specimens as small as 5.7 mm TL were collected. These specimens were extremely slender, with eye pigment and chromatophores lacking. No common Shiners (N. cornutus) were identified). Post-anal length enters pre-anal length greater than 1.9 times. Body thick and moderately pig- mented. Ventral chromatophores commence at base of caudal and extend anteriorly on the dorsal side of the yolk-sac. Gas bladder heavily pigmented. Ventral line of chromatophores may extend through the gas bladder into the opercular region where a "Y" may be formed. Dorsum with scattered chromato- phores . . . Carp (Cyprinus carpio) and Goldfish (Carassius auratus) (NOTE: Separation of carp and goldfish is difficult. Separation of these two species is probably dependent 17a. 17b. 18a. 18b. 19a. 19b. 20a. 20b. 54 on the more precocious nature of the goldfish, which is generally smaller at acquisition of specific developmental characteristics). Gut longer, such that post-anal length enters gut length more than or equal to .9 times. Post-anal length enters pre—anal length more than or equal to 1.2 times. Ventral pigmentation restricted to 4 to 10 chromatOphores on ventral margin . . . . . . . . . . . . . . Log perch (Percina caprodes) Gut Shorter, such that post-anal length enters gut length less than .9 times. Post-anal length enters pre-anal length less than 1.2 times. Ventral pigmentation more scattered with numerous, small chromatophores along most myoseptums . . . . . . . . . . . . Yellow perch (Perca flavescens) Post-anal myomeres greater than or equal to 22 . . . Walleye (Stizostedion vitreum). See 14a. Post-anal myomeres less than 22 . . . . . . . . l9 YOlk’SaC entire 0 o o o o o o o o o o o o o o o 20 Yolk-sac less than entire . . . . . . . . . . . 21 Post-anal length enters pre-anal length more than 1 time . . Common Shiner (Notropis cornutus) (NOTE: Highly unlikely, however Fish (1932) reports this species with only 14 pre-anal myomeres). Post-anal length enters pre-anal length less than or equal to 1 time. Head large. One very large oil globule or several smaller ones located posteriorly, generally causing the 21a. 21b. 22a. 22b. 23a. 23b. 24a. 55 larvae to float inverted in the surface film. Several large, round or stellate chromato- phores on ventral surface of yolk-sac. Eyes colorless at hatching . . . . . . . . . . . . . . . . . . Freshwater drum (Aplodinotus grunniens) Post-anal length enters pre-anal length less than 1 time. (NOTE: May be slightly greater than 1 if specimen is extremely pigmented and stocky) . . . . . . . . . . . . . . . . . . . . 22 Post-anal length enters pre-anal length more than or equal to 1 time . . . . . . . . . . . . 26 Total myomeres less than or equal to 28. Total length less than or equal to 6.0 mm . . . . . . Freshwater drum (Aplodinotus grunniens). See 20b. Total myomeres greater than 28 . . . . . . . . . 23 Relatively stocky with greatest depth entering total length approximately 5 times. Heavily pigmented with round chromatophores over most of body. Post-anal length may enter pre-anal length Slightly more than 1 time . . . . . . . . . . . Smallmouth bass (Micropterus dolomieui) or Rock bass (Ambloplites rupestris) Less stocky than above, with greatest depth entering total length more than 5 times. Not heavily pigmented over entire body, but may have moderate pigmentation on ventral aspect . . . . 24 Many large, round chromatophores on ventral aspect of the large, round yolk—sac. Ventral pigmentation between vent and caudal region consists of a single 24b. 25a. 25b. 26a. 56 line (which may appear double) of round chromatophores on approximately every third myomere. Urostyle oblique at hatching. Eye small and elliptical on horizontal axis, such that vertical length of eye enters greatest depth of head approximately 3 times. Snout blunt . . . . . . . . . . . . . . . . . . Trout perch (Percopsis omiscomaycus) Ventral pigmentation not as above, and much reduced. Urostyle not oblique on pro-larvae. Eye generally round and enters greatest depth of head approximately 2 times . . . . . . . . . 25 Gut short such that post-anal distance enters pre-anal distance less than .7 times. Gas bladder if apparent extends posteriorly almost to vent. Pro-larvae small and may be less than 4 mm TL . . . . . . . . . Crappie (Pomoxis Spp.) Gut longer than above. Post-anal distance enters pre-anal distance generally more than .7 times. Gas bladder if apparent is well anterior to vent. Pro-larvae may be as large as 5 mm TL . . . . . . . .'. . . . . . . . Sunfish (Lepomis spp.) (NOTE: Largemouth bass (Micropterus salmoides) may also key here). Post-anal myomeres less than or equal to 14. Gas bladder apparent at approximately 3.5 mm TL. Pigmentation restricted to several round or stellate chromatophores on ventral aspect of 26b. 27a. 27b. 28a. 28b. 29a. 57 yolk-sac and gut, and 4 or more long, slender chromatophores on ventral margin between vent and caudal region . . White bass (Morone chrysops) Post-anal myomeres greater than 14. Ventral pigmentation between vent and caudal region con- sists of many small chromatophores on each myoseptum . . . . . . . . . . . . . . . . . . . . . . . Yellow perch (Perca flavescens). See 17b. Barbels present . . . . . . . . . . . . . . . . 28 Barbels absent . . . . . . . . . . . . . . . . . 29 Tail forked. Channel catfish (Ictalurus punctatus) Tail not forked . . . Bullheads (Ictalurus spp.) Post-anal length enters pre-anal length more than or equal to 3 times . . . . . . . . . .l. . . . . . . Gizzard Shad (Dorosoma cepedianum) and Alewife (Alosa pseudoharengus) (NOTE: Difficult to separate. Perhaps the most useful characteristic is the more anterior vent of the alewife. Post-anal length enters pre-anal length only 3 to 4 times for the alewife, and generally over 5 times for the gizzard shad. Although pig- mentation is remarkably similar, alewife appear to have chromatOphores both above and below the notochord in the caudal region, while chromatophores are pri- marily restricted to below the notochord in gizzard shad. This characteristic must be viewed cautiously, however. Smelt (Osmerus mordax) may also key here, however, they are distinguished by a single row of 29b. 30a. 30b. 31a. 31b. 32a. 32b. 33a. 33b. 58 chromatOphores on the ventral aspect of the gut, rather than the double row in gizzard shad and alewife). Post-anal length enters pre-anal length less than 3 times . . . . . . . . . . . . . . . . . . 30 Pre-anal myomeres greater than or equal to 40. Ventral chromatophores restricted to a single row. Three or more very conspicuous chromato- phores present between vent and caudal region on ventral aspect. Gas bladder, if apparent, is ex- tremely posterior (only slightly forward of mid- body) and pigmented dorsally . . . . . . . . . . . . . . . . . . . . . . Smelt (Osmerus mordax) Pre-anal myomeres less than 40 . . . . . . . . . 31 Size of early post-larvae greater than or equal to 14 mm TL . . . . . . . . . . . . . . . 32 Size of early post-larvae less than 14 mm TL . . 37 Post-anal length enters pre-anal length less than 1.5 times . . . . . . . . . . . . . . . . . 33 Post-anal length enters pre-anal length more than or equal to 1.5 times . . . . . . . . . . . 34 Pre-anal myomeres less than or equal to 16. Gut extremely coiled. Several very conspicuous chromatophores on ventral margin, just anterior to the caudal region . . . . . . . . . . . . . . . . . . . White bass (Morone chrysops). See 40a. Pre-anal myomeres greater than 16. Gut not extremely coiled . . . . . . . . . . . . . . . . 38 34a. 34b. 35a. 35b. 36a. 36b. 37a. 37b. 38a. 38b. 39a. 39b. 59 Greatest depth enters total length less than 5 times . . . . Carp (Cyprinus carpio) and Goldfish (Carassius auratus). See 46a. Greatest depth enters total length more than 5 times 0 O O O O O O O O C C O O O O O O O O O 35 Post-anal length enters gut length more than 1.2 times . . . . . . . . Northern pike (Esox lucius) Post-anal length enters gut length less than or equal to 1.2 times . . . . . . . . . . . . . . . 36 Post-anal length enters pre-anal length more than 2 times . . . . Suckers (Catostomidae). See 37a. Post-anal length enters pre-anal length less than or equal to 2 times . . . Gar (Lepisosteus spp.) Pre-anal myomeres greater than or equal to 29. ChromatOphores numerous on both ventral and dorsal margins, and generally organized into a double series. Larger specimens with pigmenta- tion along lateral line . . . . . . . . . . . . . . . . . . . . . . . . Suckers (Catostomidae) Pre-anal myomeres less than 29 . . . . . . . . . 38 Pre-anal myomeres less than or equal to 16 . . . 39 Pre-anal myomeres greater than 16 . . . . . . . 44 Post-anal length enters pre-anal length l or more times . . . . . . . . . . . . . . . . . . . 40 Post-anal length enters pre-anal length less than 1 time. (NOTE: If extremely pigmented over entire body it may be slightly more than 1 time) 0 O O O O O O I O O O O O O O O O I O O 41 40a. 40b. 41a. 41b. 42a. 42b. 60 Post-anal myomeres less than or equal to 13. Gut extremely coiled. On larger specimens there may be several very conspicuous chromatophores anterior to the caudal region on the ventral margin . . . . . . . . . . . . . . . . . . . . . . . White bass (Morone chrysops) Post-anal myomeres greater than 13. Probably with a single row of chromatophores (which may appear double) on approximately every third myomere between vent and caudal region on ventral margin . . . . . . . . . . . . . . . . . . . . . . . Trout perch (Percopsis omiscomaycus) Post-anal myomeres less than 14. Gut extremely coiled and bent abruptly downward near vent. Head extremely large with small, darkly pigmented eyes located dorso-laterally. Dorsal finfold I persistent . . . . . . . . . . . . . . . . . . . . . . Freshwater drum (Aplodinotus grunniens) Post-anal myomeres more than or equal to 14. Not as above . . . . . . . . . . . . . . . . . . 42 Heavily pigmented over most of body. Relatively stocky, with greatest depth entering total length approximately 5 times. Gut relatively straight and thick . . . . . . . . . . Bass (Micropterus spp.) Not heavily pigmented. More slender than above, with greatest depth entering total length more than 5 times . . . . . . . . . . . . . . . . . . 43 43a. 43b. 44a. 44b. 45a. 45b. 46a. 61 Vent extremely anterior with post-anal length entering pre-anal length less than .7 times. Gas bladder extends behind vent on Specimens larger than 8 mm TL, and nearly so on smaller specimens . . . . . . . . Crappie (Pomoxis spp.) Vent not extremely anterior with post-anal length entering pre—anal length more than or equal to .7 times. Gas bladder does not extend behind vent . . . . . . . . . . . . . Sunfish (Lepomis spp.) (NOTE: Early post-larval Trout perch (Percopsis omiscomaycus) which were not collected in this study will probably also key here, but should be distinguished by more chromatophores on ventrum and develOpment of adipose fin in later stages). Post-anal myomeres less than or equal to 16 . . 45 Post-anal myomeres greater than 16 . . . . . . . 47 Post-anal length enters pre-anal length nearly 1 time, or only slightly more or less . . . . . . . . . . . . . . . Yellow perch (Perca flavescens) Post-anal length enters pre—anal length noticeably more than 1 time . . . . . . . . . . . . . . . . 46 Post-anal length enters pre—anal length more than or equal to 2 times. Not extremely slender with greatest depth entering total length less than 6.5 times. May have a heavily pigmented row of chromato- phores extending from caudal region anteriorly on ventral margin, over gut, and to opercular region where it forms a "Y". Head heavily pigmented on 46b. 47a. 62 dorsal aspect . . . . Carp (Qyprinus carpio) and Goldfish (Crassius auratus). See comment at 16b. Post-anal length enters pre-anal length less than 2 times. Relatively slender with greatest depth entering total length more than or equal to 6.5 times. Pigmentation variable, but with no "Y" in opercular region . . . . . Shiners (Notropis spp.) (NOTE: Difficult to separate species. See also comments at 16a. Tentative identification of Spottail Shiner (N. hudsonius) indicates chromato- phores on ventrum which may be somewhat scattered or consolidated into a double series posterior to the vent. Dorsal pigmentation generally a double series. Larvae are not extremely slender and appear rather blunt. Gas bladder very apparent and pigmented. Yolk material present until 6.0-6.5 mm TL. Tentative emerald Shiners (N. atherinoides) appear to be less pigmented. At total lengths of less than 5.5 mm even the eyes are pigmentless. In later stages a single line of pigmentation appears on ventrum, as well as several large chromatophores on top of head. At approximately 9 mm TL the chromatophores between vent and caudal region form a double series which meet posteriorly. Pigmentation along lateral line also develops at this stage. Larvae are more slender than above, with a gas bladder which is less evident at early stages). Gut long, straight and relatively thick. Post- anal length enters gut length more than or equal 47b. 48a. 48b. 63 to .8 times. May have 4 to 10 chromatophores on ventral margin. . Log perch (Percina caprodes) Gut shorter and thinner. Post-anal length enters gut length less than .8 times. May be more heavily pigmented . . . . . . . . . . . . . 48 Post-anal myomeres less than 21 . . . . . . . . . . . . . . . . . Yellow perch (Perca flavescens) Post—anal myomeres greater than or equal to 21 . . . . . . . . Walleye (Stizostedion vitreum) A PARTIAL BIBLIOGRAPHY OF LARVAL FISH WITH PARTICULAR REFERENCE TO THE WESTERN BASIN OF LAKE ERIE Armstrong, Philip B. 1962. Stages in the development of Ictalurus nebulosus. Syracuse Univ. Press. Syracuse, New York, 8 pp. Balon, E. 1959. Spawning of Lepomis gibbosus (Linne, 1758) acclimatized in the backwaters of the Danube and its development during the embryonic period. Zeit. f. Fischerei u. d. Hilfswiss. 8(N.F. l-3): 1-27. Battle, Helen I. 1940. The embryology and larval develop- ment of the goldfish (Carassius auratus L.) from Lake Erie. Ohio J. Sci., 40(2): 82-93. Carr, Margorie H. 1942. The breeding habits, embryology and larval development of the largemouth black bass in Florida. Proc. New Eng. Zool. Club, 20: 43-77. Cianci, John M. 1969. Larval development of alewife, Alosa pseudoharengus, and the glut herring, Alosa aestivalis. MastefTs thesis, Univ. of Conn., Storrs, Conn. 62 pp. Crawford, D. R. 1923. The significance of food supply in the larval development of fishes. Ecology, 4(2): 147-153. Fish, Marie Poland. 1932. Contributions to the early life histories of sixty—two species of fishes from Lake Erie and its tributary waters. Bull. U. S. Bur. Fish., 47(10): 293-398. Lippson, Alice J. and R. Lynn Moran. 1974. Manual for identification of early developmental stages of fishes of the Potomac River estuary. Maryland Dept. Nat. Resources, Power Plant Siting Program. PPSP- MP-l3. 282 pp. Mansueti, Alice J. 1964. Early development of the yellow perch, Perca flavescens. Chesapeake Sci., 5(1-2): 46-66. Mansueti, Alice J. and Jerry D. Hardy, Jr. 1967. Develop- ment of fishes of the Chesapeake Bay region. An atlas of egg, larval, and juvenile stages. Part I. Natural Resources Institute, Univ. Maryland. 202 pp. 64 65 Mansueti, Romeo J. 1964. Eggs, larvae, and young of the white perch, Roccus americanus, with comments on its ecology in the estuary. Chesapeake Sci., 5(1-2): 3-45. May, Edwin B. and Charles R. Gasaway. 1967. A preliminary key to the identification of larval fishes of Oklahoma, with particular reference to Canton Reservoir, including a selected bibliography. Oklahoma Fish. Res. Lab. Bull., 5: 1-33. Miller, Robert R. 1960. Systematics and biology of the gizzard shad (Dorosoma cepedianum) and related fishes. U. S. Fish and Wildl. Ser., Fish. Bull., 60(173): 371-392. Morgan, G. D. 1951. The life history of the bluegill sunfish, Lepomis macrochirus, of Buckeye Lake, Ohio. J. Sci. Lab., Denison Univ., 42: 21-59. Morgan, G. D. 1954. The life history of the white crappie (Pomoxis annularis) of Buckeye Lake, Ohio J. Sci. Lab., Denison Univ., 43: 113-144. Nelson, William R. 1968. Embryo and larval characteristics of sauger, walleye, and their reciprocal hybrids. Trans. Amer. Fish. Soc., 97(2): 167-175. Norden, Carrol R. 1961. The identification of larval yellow perch, Perca flavescens and walleye, Stizostedion vitreum. COpeia 1961(3): 282-288. Norden, Carrol R. 1967. Development and identification of the larval alewife, Alosa pseudoharengus (Wilson), in Lake Michigan. Proc. 10th Conf. Great Lakes Res. 1967: 70-78. Nordquist, H. 1915. Contributions to the knowledge of the larval stages in our freshwater fish. Ark. Zool., Siefert, R. E. 1969. Characteristics for separation of white and black crappie larvae. Trans. Amer. Fish. Soc., 98(2): 326-328. Smallwood, W. M. and Mary L. Smallwood. 1931. The develop— ment of the carp, Cyprinus carpio, I. The larval life of the carp, with special reference to the develop— ment of the intestinal canal. J. Morphol., 52(1): 217-231. Snyder, Darrel E. 1971. Studies of larval fishes in Muddy Run pumped storage reservoir near Holtwood, Pennsylvania. Master's thesis, Cornell Univ., Ithaca, New York. 68 PP0 66 Steward, N. H. 1926. Development, growth, and food habits of the white sucker, Catostomus commersonnii. Bull. U. S. Bur. Fish., 42: 147-184. Taber, Charles A. 1969. The distribution and identification of larval fishes in the Buncombe Creek Arm of Lake Texoma with observations on spawning habits and rela- tive abundance. Ph.D. thesis, Univ. Oklahoma, Norman, Oklahoma. 120 pp. Warner, E. N. 1941. Studies on the embryology and early life history of the gizzard shad, Dorosoma cepedianum LeSueur. Ph.D. thesis, Ohio State Univ., Columbus, Ohio. 22 pp. Wrenn, W. B. and B. G. Grinstead. 1971. Larval develop- ment of the smallmouth buffalo, Ictiobus bubalus. J. Tenn. Acad. Sci., 46(4): 117-120. 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