W DISTRIBUTION OF FISH POPULATIONS NEAR A THERMAL DISCHARGE INTO WESTERN LAKE ERIE Thesis for the Degree of M. S. MICHIGAN STATE UNIVERSITY DENNIS SCOTT LAVIS 1976 ' III!IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII SSW? ABSTRACT DISTRIBUTION OF FISH POPULATIONS NEAR A THERMAL DISCHARGE INTO WESTERN LAKE ERIE By Dennis Scott Lavis This study was designed to assess the impact of the Monroe Power Plant on fish distributions in western Lake Erie. The plant uses a once- through cooling system which releases up to 85 m3/sec of warmed (generally about 10 C) water into western Lake Erie. Data were collected from May 1970 to June 1971 for preoperational estimates and from June 1971 to June 1975 for postoperational estimates. Fish were sampled with a bottom trawl and gill nets. Samples were taken from the discharge canal, the plant intake, in the lake near the mouth of the discharge canal, and at two reference stations beyond the reach of the thermal discharge. Although distributions of fish species changed during the study, the abundance of fish in the study area varied without trend. After prelim- inary operation in 1971, when the discharge had stabilized, goldfish, carp, and channel catfish were attracted to the discharge canal all year. Yellow perch, alewives, emerald shiners and spottail shiners almost constantly avoided the discharge canal. White bass, freshwater drum, and gizzard shad appeared to be sometimes attracted and othertimes repelled. Neither growth nor condition appeared to be appreciably influenced by residence in the thermal discharge. DISTRIBUTION OF FISH POPULATIONS NEAR A THERMAL DISCHARGE INTO WESTERN LAKE ERIE By Dennis Scott Lavis 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 1976 ACKNOWLEDGEMENTS I wish to express my deep appreciation to Dr. Richard A. Cole for his advice and aid in preparing this manuscript and also to Drs. Eugene W. Roelofs, Peter I. Tack, and Richard W. Merritt, members of my gradu— ate committee, for their advice and review of this manuscript. A note of appreciation is extended to Mr. Benjamin R. Parkhurst and Mr. Thomas J. Edwards for their contributions early in this study. To Mr. Steve Kilkus and Mr. Charles Warner who aided in data collection on many cold, blustery days in the field and to the many graduate students who provided intellectual stimulus, I am most appre— ciative. This study was supported by funds from the Detroit Edison Company to the Institute of Water Research at Michigan State University. Partial tuition funding was made possible through a grant from the Environmental Protection Agency. Finally, to Lucille A. Lavis whose continual support, reassurances, and devotion were ever present throughout my graduate career, I am deeply indebted. ii TABLE LIST OF TABLES . . . . . . . . . . LIST OF FIGURES . . . . . . . . . INTRODUCTION . . . . . . . . . . . METHODS . . . .‘. . . . . . . . . The Study Area . . . . . . . western Lake Erie . . . The Monroe Power Plant . Sampling Sites . . . . . Data Collection . . . . . . Data Analysis . . . . . . RESULTS . . . . . . . . . . . . Horizontal Distributions Trawl . . . . . . . . . Gill Nets . . . . . . . Vertical Distributions . . . Growth and Condition . . . . Fish Kills . . . . . . . . . DISCUSSION . . . . . . . . . . . Distributions . . . . . . . . Population Impact . . . . . Management Implications . . LITERATURE CITED . . . . . . . . . APPENDIX . . . . . . . . . . . . . OF CONTENTS iii 17 17 17 27 30 32 NB NA NA 1+7 50 52 56 Table A2. A3. AN. A5. A6. LIST OF TABLES Power plant load, pumping rates, wind speed and direction, and length of the thermal plume recorded in 1973-7h at the Monroe Power Plant . . . . . . . . . . . . . . . . . . . . Wind direction and speed during August 197h . . . . . . Numbers and biomass per 60 trawls of fish taken during the study period 1970-1975 in western Lake Erie Total catch data for gill net collections near the Monroe Power Plant in Lake Erie from 1971 through l97h Mean length (mm) at the end of the first growing season of the abundant species collected near the Monroe Power Plant during the years 1970 through 1975 . . . . . . . Condition factor (K) of the abundant fish species taken in the study area during the study period . . . . . . Mean length (mm) at the end of the growing season of perch, carp, goldfish, and freshwater drum taken near the Monroe Power Plant during the years 1970-197A . . . . . . Numbers of individuals per hectare and totals found in the discharge canal and adjacent study area seasonally . Sampling dates included in the analysis of variance for trawl data . . . . . . . . . . . . . . . . . . . . Tukey's multiple range test among stations for all species . Tukey's multiple range comparison test among years of the study for all species . . . . . . . . . . . . . . . Tukey's multiple range comparison test for yellow perch, carp, and goldfish . . . . . . . . . . . . . . . . . Tukey's multiple range comparison test for gizzard shad, freshwater drum, and alewife . . . . . . . . . . . . . . Tukey's multiple range comparison test for white bass and emerald shiner . . . . . . . . . . . . . . iv Page 11 18 28 3h 36 38 AB 56 57 58 59 6O 61 LIST OF FIGURES Figure l. 10. Map of the study area giving locations of the sampling sites used for trawling and gill netting . . . . . . . . . . . Temperature elevation of the cooling water between the intake and outfall varied with variations in power load and pumping rates during the entire study . . . . . . . .7. . . . . . . . Erratic temperature fluctuations and dissolved oxygen concen— trations were characteristic during the early years of the study. As plant Operation stabilized, so did the temperatures and oxygen levels recorded in the discharge canal The length and direction of the thermal plume in Lake Erie varied with variations in plant power load, pumping rates, and wind speed, and direction . . . . . . . . . . . . . Mean number of fish captured per trawl during the study period throughout the entire study area . . The seasonal Species diversity within the study area . . . . , The relationship of Species evenness and Species diversity based on weight and numerical measures of abundance . . Mean number of young-of—the-year captured per trawl seasonally at each station. T1 and T3 represent the north and south lake reference station respectively; T2 was located in the Raisin River. An asterisk indicates no data were obtained . . . . . . . . . . . . . . . . . . . . . . . . Mean number of age I and older fish captured per trawl seasonally at each station . . . . . . . . . . . . . . . . . Seasonal distributions of fish captured by horizontal gill nets. A control net was set near the south lake reference station while the plume net was set near the mouth of the discharge canal. Directional movement of the fish at the time of capture is denoted by south, a direction going away from the discharge canal and north, a direction heading toward the discharge canal . . . . . . . . . . Page 12 21 22 23 2h 25 29 Figure ll. 12. 13. Seasonal distributions of fish captured by vertical gill nets in the discharge canal during 1972-197h Vertical distribution of fish captured by vertical gill nets during day-night comparison studies in 1976 . . . . Mean annual growth rates for perch, carp, goldfish, and freshwater drum collected in the study area during 1970 through 1975 . . . . . . . . . . . . . . . . . . . . . vi Page 31 33 N2 INTRODUCTION Steam electric power generation may require up to ten times as much cooling water from the Great Lakes over the next few years (Denison and Elder, 1970). The demand for cooling water in the Great Lakes area is more than all other intake withdrawals for municipal, industrial, and agricultural purposes. In the process, large amounts of water are being warmed and returned to natural waters. The potential impact on aquatic communities from heated water discharges is of pressing concern to the aquatic resource manager. The alternatives to once-through cooling are usually much more expensive; therefore, it is imperative to determine the actual impact of thermal discharges on aquatic communities to aid in management decisions. The purpose of this research was to study the impact of a thermal discharge on the distribution of fish populations over a 5—year period in western Lake Erie. Most investigations of thermal effects historically have been assessments of thermal preferences and thermal tolerances with controlled laboratory tests (Kennedy and Mihursky, 1967; Raney and Menzel, 1969; Beltz, §t_§l,, 197A). It was necessary, because of the limitations associated with laboratory experiments, to conduct field investigations to verify or refute the predictions generated from controlled experiments. Although results of other field investigations have been published (Marcy, 1976; Dryer and Benson, 1957; Drew and Tilton, 1970; Gammon, 1973; Proffitt, 1969; Neill and Magnuson, 197A), this study was unique because it 2 incorporated preoperational and Operational observations around a large power plant at an intensity which allowed unusual statistical confidence. It also was the first comprehensive study of this type reported for Lake Erie. The results of this study Should contribute to future lake manage- ment decisions. METHODS The Study Area Western Lake Erie The study area parallels about 15 km of Lake Erie's west shore near Monroe, Michigan, and the mouths of the Raisin River and the discharge canal at the Monroe Power Plant (Figure 1). The shallow, western basin of Lake Erie receives about 95% of all drainage into the lake, and the Detroit (90%) and Maumee (h%) Rivers provide most of that flow. These major tribu- taries, which dictate the water quality in the study area, reflect the municipal and agricultural activity in the watershed. The Maumee River, which enters south of the study area, carries particularly high sediment loads to the lake (IJC, 1969). These main tributaries, along with the prevailing southwest winds in the area, tend to maintain a clockwise cir- culation in the southwest corner of the western basin so lake currents most commonly move northward through the study area. The average depth of the western basin is 7 meters and depths in the study area range from 1 to 8 meters. The interaction of moderate winds over the shallow basin and tributary loading with suspended matter maintains consistant high turbidity in the study area. The Raisin River drains into the lake near the center of the study area. Even though the Raisin River contributes less than 0.5% of the total input to the lake basin, it has a strong local impact on lake water quality (Carr and Hiltunen, 1965). In the past, the Raisin River was recognized as Monroe 3,85, Bay 4". - [n 370 Plum : Creek ‘\ (7“, K Discharge i ‘.\_. anal 4 T 16‘ - <0 L ‘%2b1\4 ' 4/30 Ikm 6» H La PIaisance Ba RAISIN y RIVER I BREST s :3 .' ‘7'an L——.—l . T kilometer . .a‘ ~c TRAWL STATIONS ‘ HORIZONTAL GILL NETS MAUMEE b . $6 VERTICAL GILL NET AREA ‘7 BAY Flg'ure 1. Map Of the study area giving locations of the sampling sites used for trawling and gill netting. 5 severely polluted, primarily because of extreme oxygen depletion in the lower reaches (Wright, 1955). It receives both industrial and municipal 'wastes from the City of Monroe. However, new waste treatment facilities art Monroe, completed in 1972, may have measurably improved the quality of the Raisin River water. The biota of the western basin has changed in past decades, apparently in: response to human activity in the watershed. Beeton (1961), Carr and Hijltunen (1965), Davis (196A), Verduin (196A) describe past transitions in tkue species composition of invertebrates and algae from that indicative of nadsurally fertile, moderately productive, mesotrophic waters (Hexagenia sp>., diatoms, etc.) to that associated with highly productive, eutrophic waiter (chironomids,'b1ue-green algae, etc.). The yield from commercially fiushed populations has also changed composition from one dominated by Trigmly valued fish Species to one dominated by economically less desirable Species. Although many factors may have contributed to this change in fiesh populations, overfishing is believed to be a primary cause (Hartman, 1972; Regier and Hartman, 1973)- EflgggMonroe Power Plant The Detroit Edison Company constructed and operates the Monroe Power Ifilixnt on a filled portion of the Raisin River delta. The plant now pro- dllces up to 3150 megawatts and requires up to 85 m3/sec of cooling water 3f<>r its once-through cooling system. The primary sources of cooling water Ett‘e Lake Erie and the Raisin River. The cooling water intake lies 650 m 11Ibstream from the river mouth. Nearly all of the river water is drawn for ‘3C3cfling, but during periods when river discharge falls Short of cooling ‘VErter demand the deficit is supplied by lake water drawn "upstream" through tflle river channel. At full plant operation, lake water contributions are 6 about 80 to 85% of the water annually required for cooling purposes. The relative contributions vary seasonally from almost all river water in early Spring to almost all lake water in late summer. Water taken into the plant passes through the condenser system and into a 2 km long discharge canal. Temperature elevation at the condenser varies as a function of power generation and the amount of water being pumped. Both have varied greatly since the plant began operating and tem- perature elevations have varied (Figure 2) accordingly from 0 to at least 13 C. The greatest thermal elevations across the condenser occurred during winter when cooling water pumping rates were reduced. The study period spans a preoperational year and four following years during which time the plant grew from one to four identical power-generating units. The first unit began operating in May 1971 and the remaining units followed at approximately one-year intervals until completion in May 197A. Operation started out erratically but stabilized as more units contributed power. With the completion of each unit, more coolant was required from the source waters in the river and the lake and the relative proportions of each changed. In 1971, most of the demand could be satisfied with river water and the quality of water in the discharge canal reflected the relatively poor water quality found in the river. As more lake water was pumped in later years, the quality of the water in the discharge canal improved. This operational history is reflected in the temperature and oxygen concentrations measured in the discharge canal (Figure 3). The size of the thermal plume in the lake has also shifted with thermal loading, pumping rates and wind. The variability in plume size and position is indicated by the relation of wind and plume measurements made in 1973 and 197A along the midline axis Of the plume (Ecker and Cole, 1976). Table 1 shows that the main direction of the plume axis and the length of the «J Moo 70 soon ‘ _ 240° n 3oz” '93 5. : n .0002. o 4,, 0'3 §I ‘ 2.1 ”no 3 4 A .-«..——c I. P. N ‘ F. f ' pm 1 \r n V'./ “n I . 4 b“ u: r} f “ I an N I ,. \V—J -. .n a :-’ an V \A .u ‘ g 0-1 *‘HW “\ m '3 . p z ”-1 K, I. :39 g . { ,“ I‘d A ‘ 4 b" r: H Md .. h 4 .‘ A p. d O-I .4 0‘ ° “:TW'I ..... I .. I -. I ~ I -. I M T“"""I “""T'""I "~- 10-: A)... 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SIX but gzou 5m fit «8:22 5m: 5m a“: 5052 232 SHINER ion g01ng PERCH Directional movement of the fish at the le the plume net was set near the mouth of the discharge canal. hl A control net was set near the south lake reference ion w Seasonal distributions of fish captured by horizontal gill away from the discharge canal and north, a direction time of capture is denoted by south, a direct heading toward the discharge canal. WHITE BASS nets. stat Figure 10. 30 None of the Species exhibited any preferential directional movement at the time of capture. They were Just as likely to be taken in the gill nets in a position facing away from the mouth of the discharge as facing toward it. Gill net capture data generally support the trawl data which indicate that certain species avoid the discharge canal while other species are attracted to it. It also supports indications that the lake area, periodically traversed by the thermal plume, is not decidedly influenced by plume incursion. Vertical Distribution Vertical distributions of the major Species caught in gill nets in the lake (Figure 10) and discharge canal (Figure 11) indicate that many individuals were located above the effective sampling area of the trawl. Therefore, trawl data could misrepresent to some extent the actual areal distributions of some species. The ranking of Species abundance in the gill nets was generally comparable to the trawl catch with some exceptions. Yellow perch and shiners were most frequently captured near the bottom and, as a result, their relative abundances may have been overestimated by trawling. On the other hand, gizzard Shad, alewives, and white bass exhibited a preference for surface waters and their relative abundances may have been underestimated. Carp, goldfish, and freshwater drum appeared to be evenly dispersed throughout the water column and did not seem to favor either the surface or bottom waters. Likewise, channel catfish were dispersed evenly in the water column and not strongly concentrated toward the bottom as would be expected. MEAN NUMBER CAUGHT PER SEASON MEAN NUMBER CAUGHT PER SEAS“ MEAN NUMBER CAUGHT PER SEASON MEAN NUMBER CAUGHT PER SEASON 31 to .l Bill. 1 'r EJ'W CARP I I I4" ' ’I d I 5r 4 3 '3 2 l 0 I SHRLLW SET ‘ M‘p s57 ' ; DEPTH IN METERS FROM SURFACE w I .Ign , 4 am: I ALEWIFE I'm" 7 I “I .r I I I I 3:» I ' I I I 2r l I l I L 0 4 3 2 I o 3 7 6 3 4 3 z I o suALLow SET 5', our SET § DEPTH IN METERS FROM SURFACE IOr I II I l t Ejnu I I or. firm SHINER ' Inn 7r 5 I- 5 I- 4 I. 3»- , L I I g 0' 4 2 I o o 7 5 “4 “3 "I ? smuow sat I, DEEP sn 5 DEPTH IN METERS FROM SURFACE II: ”t man u Inn DRUM .Im 1 n- 6 r- s P 4 h 3 h 2 D- " I .__11_J1 n I < 35 I II a 0 4 3 2 I c a 7 e 3 4 3 2 I o SHALLow SET I use? 5:1 ,1 oapwfi Figure ll. IN METERS FROM SURFACE HT R SEASON MEAN NUMBER CAUGHT PER SEASON MEAN NUMBER CAUG PE HEAN NUMBER CAUGHT PER SEASON MEAN NUMBER CAUGHT PER SEASON 05 oo 0 ‘l O OO O 0 O B an [Jan I'm” A suALLow sn 5 2 ' GOL DFISH I 9 7 6 5 4 3 2 I DEEP SET DEPTH IN METERS FROM SURFACE 8 I'll a an I In: SHAD ° 4 3 c " snauov sex ; our SET g DEPTH IN METERS FROM SURFACE I0 ’I Eflnn IL B-m CHANNEL CATFISH . um ’I 6t 5L 4 >- 3L 2 I- ! h I I 0 4 3 I < 4 I SHALLow SET 5. our SET 5 DEPTH IN METERS FROM SURFACE IO 25. r Kluc I6.— Dun WHITE BASS I4. .m' :2- IO" a. 6» .5 2L _.u.n.-_In.._n ° 4 3 2 I o a 7 6 s 4 3 2 I 1‘) SHALLow 5:7 5" 0129 SE? 5 DEPTH IN METERS FROM SURFACE Seasonal distributions of fish captured by vertical gill nets in the discharge canal during l972-l97h. 32 From 1971 to 1975 gill nets were fished overnight to increase capture effectiveness. Meanwhile, trawling was conducted during the day for prac- tical reasons. Therefore, results of the two techniques are not simply comparable. In 1976 vertical gill nets were fished both day and night during a short experiment to determine the effect of diurnal variation (Figure 12). Results indicate that gizzard shad, freshwater drum and longnose gar were either more active at night than during the day or more capable of avoiding day sets. White bass and carp were more active during the day. Channel catfish capture rates appeared consistant between day and night. Vertical distribution of net capture in shad and carp was influenced by time of day (Figure 12). Both species appeared to favor bottom.waters during the day and move up into the water column at night. However, this could also be the result of net avoidance in the lighted surface waters during the day rather than some diurnal behavioral factor. Changes in the vertical distributions between day and night of the scarcer species were not detectable at the intensity sampled. Growth and Condition Neither growth (Table 5) or condition factor (Table 6) of fishes in the vicinity of the Monroe Power Plant appear to be greatly affected by thermal discharging. The mean length of young-ofethe-year fish at the end of the growing season of those species found in the discharge canal is not significantly different (a = 0.05) from the same species collected at the lake stations. Similarly, the growth rates of the major Species are not statistically different among stations and years of the study (Table 7, Figure 13). No significantdifference (a = 0.05) in condition factors could be detected in fish from the lake and those taken from the discharge canal either seasonally or annually. 33 2| 20. I9 SHAD F IB ITJ I6. I5- I4. l3-I I24 F ”-4 IO-I 9« — F a. 7-1 '-I 1 51 34 _« 4 4. 3. h i IN] 432I 432I DAY WT smuow 5:7 our 51’? DEPTH N METERS FROM SLRFACE MEAN NUMBER PER SET 877654321 NIGHT 2|. ZO-I I94 CARP I84 I‘H I6. I5. I43 I3. I24 II. IO. MEAN ma PER SET 2’ I-I 0 an e NEED 4 3 2 l 4 - 3 2 I B 7 6 5 4 3 DAY NIGHT DAY SHALLOVI SET DFEP SET DEPTH IN METERS FROM SURFACE 2| 432 HT sQQU D 2| 20.. I9. I8... ‘ 'l-I '6‘ I5. I3-I l2d ”-4 I0: S-I Bu 7. DRUM GOL DFISH WHITE BASS MEAN MR PER SET GOLDFISH, CHANNEL CATFISH GOLDFISH 5.. 4.. CHANNEL CATFISH “D “B [:Zlonw CHANNEL CATFISH CHANNEL CATFISH , m7: BASS ”3 m7: sass. GAR onum , can , DRW, E A 1 3 2 I mm mum: 5:! our 5:: DEPTH N METERS FROM SLRFACE DRUM GAR GAR 1: 5H L— oar" ”D F._._’ GAR 2.. '~ u l b 3 “TE BASS ‘Donw ‘3 m7: sass “t3 CHANNEL CATFISH, °::J new, ‘D “3 “D 32I DAY O O D 4 EU 9 Figure 12. Vertical distribution of fish captured by vertical gill nets during day-night comparison studies in 1976. 3h xx xxx mm xx mm xxx 00H xxx xxx xxx mB xx xxx 20H mp xx xxx mHH wma mp xxx :9 xx ONH NMH mp xx mHH MHH ONH OON woa mE xx xxx xxx ow xx xxx wad xxx xxx NHH NB xx xxx OOH mp xx xxx :HH 10H m: mma HE mpma xx xxx xxx xx xx xxx mp xxx xxx xxx m6 mp mm NHH ow xx xxx poa Hma pm :HH :9 xx w» wma mp xx xxx mm mma mm Hex me xx mm 03H mp xx xxx mm HQH mma 02H NB xx ox mmx ox xx xxx xxx Hma woa moa He mpaa xx xxx xxx xx xx OHH mp OMH xxx xxx me xx xxx xxx xx xx moa mm xxx mma mma :8 xx xxx mOH 0p xx MOH HHH xxx xxx ®NH mB xx mma xxx mm mm woa xxx xxx xxx Nma NB mm 3p ONH ow Ow pOH mOH mad Mp Hp HE HpmH xx mma xxx 0: xx xxx moa xxx xxx xxx me mp wp 2w mm xx xxx OOH NHH 00H mp :9 xx xxx mm mm pm OHH NHH xxx mp mad me xx mm Op mp gm mm woa xxx mm mma NE xx gm mp wx xx xxx max OOH mm xma Ha OpmH zmxxpmo mmmp esxo xmcxnm xmcxnm maxsmxa exam nmxxeaoo mxxo noxmm coprpm Hmccxno mafia; fixappomm oxmxmem and hump .mpmH smSOHQP Opma mgwmh map wcwhsc pcwam hmzom oOMGoz map paw: Umpooflaoo mowomam pcmoQSQG mnp mo acmwwm mafizopw pmpflm map mo cum mSp pa AEEV npmsma cam: .m mHQwB 35 mw pna oma xx xx xxx mm xxx mpm xxx me mo xxx omx ow mm mm HOH :mH mma xxx :9 On max HHH m» xx :0 mm Ema Hm mOH me xx xxx xxx :p pm mm 20H pmH mad mm NB xx om mad mm mm Hm mm mmH mm NHH HE :pma zmxxxwo mmxp asxm xmmxnm xmcxnm xxxsmxa exam :mxxexou mxwo soxmm :oxpwxm Hmccxno mpxsz Hxappomm eamxmem and Adm» .omssquoo .m magma xxx H H N H N.H w.o ®.O 0.H O.N w.H 0.H m8 xxx :.H H.H m.o 0.0 0.H m.H 0.H ®.H m.H :8 xxx N.H H.H 0.H w.O ®.O H.H N.N m.H N.H MB xxx m.H N.H xxx 0.H ®.O N.H :.N ®.H N.H NB xxx H.H H.H 0.H p.O w.o 0.H O.N m.H N.H HE mpma m.o xxx H.H 0.H H.H :.H H.H m.a m.H m.H me 0.H H.H H.H 0.0 m.o H.H H.H o.m m.a xxx :9 m.O N.H H.H 0.0 H.H xxx 0.H O.N :.H N.H MB m.o m.H H.H m.o m.o xxx H.H o.m 4.x m.H we 0.H m.H 0.H ®.O v.0 xxx 0.H O.N m.H N.H HE mpma xxx xxx xxx xxx xxx xxx xxx xxx m.a 0.H me xxx xxx xxx xxx xxx xxx xxx xxx m.H H.H :9 xxx xxx xxx xxx xxx xxx xxx xxx :.H H.H me xxx xxx xxx xxx xxx xxx xxx xxx :.H H.H NB xxx xxx xxx xxx xxx xxx xxx xxx m.H m.H HB Hpma xxx xxx xxx xxx xxx xxx xxx xxx xxx m.H we xxx xxx xxx xxx xxx xxx xxx xxx m.a m.H :9 xxx xxx xxx xxx xxx xxx xxx xxx 0.H m.H m9 xxx xxx xxx xxx xxx xxx xxx xxx :.H N.H NB xxx xxx xxx xxx xxx xxx xxx xxx :.H m.H HE OpmH swampwo mmwp Edy: pmcfinm hmcHLm mmflzma< omnm Smwmoaoo mhoo nohmm Gprwpm Hmccxno mpxnz wappoam caaxmem ecu Ramp .cofixmg stpm xxx mcfipsc wmxw stpm opp aw coxwp mmfiomam nmfix pcwccspw map go Axv AOpowm sewpficcoo .m magma Continued. Table 6. Year Channel catfish White Spottail Emerald shiner and Station bass Drum shiner Carp Goldfish Shad Alewife Perch *5“!- *** *** *9”!- 1.2 1.1 0.8 0.8 1.0 1.2 2.0 1.6 1.2 197k Tl Mm Hr-i ON HH c>c> r+r+ [‘0 O O O\ p h h L p h p r D L 0” ca oo om om oo. oo— 1 1 N N 9 m w. n a room m :00 m w W Iooc ( 100¢ ( 1000 Icon Ioom woow loos noon wooo vooo :23 Woom 12.138 Hoom nu uo< ua< :9m 0 s m n c n N . Pp — plP _ p L b _ L ON on om oo. .l _| M. ...oo~ fl 9 9 1 1 H H m m nooc ( 1ooo loom Ioox ooa azxu woom zucmu toanu> com 1&3 Fish Kills Dead fish were only infrequently observed in the discharge canal at the Monroe Power Plant. On two occasions during the winter of 1973 large numbers of dead gizzard shad were observed in this area. At these times, interruption in plant operations caused rapid temperature drops of over 10 C. Since that time, plant Operation has stabilized and no kills have been observed. DISCUSSION Distributions The abundant fish species in the study area can be divided into three distinct behavioral groups: those fish which tended to avoid the discharge canal at all times, those that were attracted at all times, and those that responded variably. Yellow perch, emerald shiners, and alewives avoided the discharge canal. Gizzard shad and freshwater drum were repelled or acted indifferently during the warmer months; however, they were attracted during the cooler months. Large white bass apparently entered the canal mostly during spring spawning runs. Carp, goldfish, and channel catfish were attracted to the discharge canal at all times of the year. Erratic plant operation in combination with poor quality water repelled most fish populations when the power plant began preliminary operation in 1971. The unpredictable influx of poorly oxygenated river water apparently did not kill fish; at least no fish kins were observed at that time. As the plant approached completion, thermal discharging stabilized, oxygen concentrations in the discharge canal improved and more fish were captured in the canal during all seasons. The results of this study do not fully concur with results reported from other investigations. Perch avoided thermal discharges at some sites (Alabaster and Downing, 1966; Neill and Magnuson, 197k) and were attracted to others (Miller and DeMont, 1972). The preferred temperatures of adult yellow perch, which range from 18 to 2b C (Ferguson, 1958; McCauley and Read, 1973), indicate that perch could easily move into the heated waters && AS at Monroe between October and April and remain near their preferred tempera- tures. Whether perch move into warm waters of a thermal plume appears to be site-dependent and may not be controlled strictly by temperature. Rather, some unidentifiable hydrological, chemical, or trophic characteristic of the discharge canal and thermal plume may be responsible. If yellow perch continue to avoid the discharge canal at Monroe, there appears to be little possibility of reproductive failure caused by winter exposure to elevated temperature as postulated by USFWS (1970). Emerald shiners and alewives avoided the discharge canal in this study and elsewhere (Barans and Tubb, 1973; Patriarch, 1975). Laboratory studies indicating thermal preferences of alewives (Dorfman and Westman, 1970; Meldrim and Gift, 1971) appear to conflict with the results of this study. As with yellow perch, the apparent avoidance of the discharge canal may not be caused entirely by the elevated temperatures. Rather, some related character may be working in combination with temperature. During the winter and spring large numbers of gizzard shad were attracted to the discharge canal at Monroe. These results have also been reported at other sites around the country (McNeeley and Pearson, 197&; Proffitt, 1969; Dryer and Benson, 1957; Miller and DeMont, 1972). Fresh- water drum react more or less indifferently to the discharge canal environ- ment during much of the year. There appear to be no other published remarks about the behavior of this Species around thermal discharges. Reported distributions of white bass near thermal discharges appear inconsistant with those of this study. White bass were attracted during the winter to a thermal discharge studied by Miller and DeMont (1972) and Neill and Magnuson (197A) report that large yellow bass (Morone mississipr piensis) were attracted to thermal discharges while young individuals were repelled. The above findings, and those of this study, imply that the h6 differences in behavior from one site to anther may be caused by some factor, such as river water quality, that could change in the future. As in this study, carp, goldfish, and channel catfish appear to be consistently attracted to thermal discharges at many other sites (Neill and Magnuson, l97h; Marcy, 1976; McNeeley and Pearson, 197h). The high temperature preference (Neill and Magnuson, 197&; Roy and Johanson, 1970; Andrews and Stickney, 1972), along with the omnivorous feeding habits of all three species may explain why they, more than any of the other species collected, have increased in abundance in the discharge canal and remained abundant during all seasons. The behavioral response of different fish species in this study to the discharge canal could not be predicted entirely by the reported tempera- ture preferenda of the various species involved. Most of the species that tend to avoid the thermal discharge have temperature preferenda that would allow inhabitation of the canal at some times during the year if tempera- ture were the deciding factor. The fact that avoidance occurs in spite of this, suggests that some factor or combination of factors-chemical, trophic, or hydrological, may be effecting the avoidance reaction. If this is true, the Species that presently avoid the discharge canal may change their dis- tributional patterns in response to non-thermal environmental changes sometime in the future. The abundance of fish over the period of study has exhibited great spatial and seasonal variability. Abundances from one season to the next and abundances between stations were often significantly but inconsistantly different. No consistant trends could be recognized that would be sugges- tive of power plant operation. These data imply that fish in the vicinity of the Monroe Power Plant are continually moving in and out of the discharge canal and through various parts of the study area over relatively short 147 - periods of time. Many of the fish species in the study area are capable of moving long distances. For example, walleye regularly move 5 to 7 km (Magnin and Beaulieu, 1968) and up to 160 km (Wolfert, 1963), and channel catfish regularly move 16 to 63 km and up to 159 km (Magnin and Beaulieu, 1968). Both gizzard shad and alewives reportedly move in and out of shallow water for Spawning (Bodola, 1966 and Graham, 1956). A small percentage of fish in the nearby lake area make up the dis- charge canal population (Table 8) according to computations of mean density made from trawl and gill net data. Local distributional adjustments to the thermal discharge, as reflected by changes in abundance at sampled stations, cannot be separated with the sampling intensity applied because less than 10% of the total local population seems to be involved at any one time. Even though the mean density per hectare of the discharge canal may, at times, exceed the mean density per hectare in the lake by more than 10 times, this still represents a small percentage of the total fish in the study area. Therefore, decreases in abundance in the lake, because of'emigration to the discharge canal, are unidentifiably small. Population Impact There have been changes in the local distribution of some fish Species around the thermal discharge at Monroe but there has not been any indication of an important impact on the total abundance of species populations in the plant vicinity. Although a few species appeared to decline in abundance, much of this change may be explained by natural variability which stems from inherent population vulnerability to recruitment failure. Many of the abundant Species in the area have only 1 or 2 important spawning year classes represented; including yellow perch, white bass, shiners, and clupeids. MB .mwcwmsonp :fi umpcmwmpmmu mam mnmnEdc Hmpoe m .mz 003m mdS mono wane .chwo mmpwcomwp opp mo :psoE map Eopw Ex m mo mSHUwp w :pfiB cmnfiaomESoaHo mono pmnp mm UmpwHSUHwo mm: mono h65pm mp8 m .wfl O: was). chwo wwhwflomfic mflp MO wmhw $39 H s.o H.Hw mmom o.mwo.ma ommm m.H m.:sm maaw :.omm.mH wamm m.m o.wmm ooam o.mew.m mm: mawpoe * m. w :.amw.ma Hwom * ;.m own m.mo;.e mama * s . m.amm :mH meaSmH< 0.0m :.m own 0.Hm a o.wm w.mm ssmfi w.m~H mm o.ma m.mw swam :.mHH Hm gmfiepmo Hmccwno * m. m s.sma mm * H.0 m m.~mm a: m.m m.w omm 0.Hmm mm msmcanm m.o o.m mm m.wss mm 0.H m.m mam w.mmm sea o.m m.oa. mwm ;.Hmm a: saga m.m m.m om :.oaa mm * m.m o» o.wmm.~ oesa o.m m.m mm w.w: m mmw o.m m.mm 0mm m.wae mmH o.m m.mma osmm :.msm.m was m.ooa H.mw meow m.ma m uwam * u . 0.0mm mm * n ' :.mam Hm * H.0 m m.m0m mm nopmm o.mfi s.mm awn :.:mfi mm m.: o.mm 0mm o.mms om :.a :.mm wmw m.mma aw emaueaoo o.sH m.Hm mam w.mmH mm m.m m.m ama m.maa em. ~.m m.» mwa o.moa om mtwo m .02 .wz .02 .mn R .02 .m: .02 .w: & .02 .w: .02 .mn mmflommm Haves .oz Hapoe .oz Hapoe .oz proe .oz Hapoe .oz apoe .oz g mo mfimhawcm one cfl UmUSHocfl mmpwp mcflamfiwm .H< manna 57 Table A2. Tukey's multiple range test among stations for all species. Numbers of Individuals Stations Years 1 2 3 h 5 1970 8. a a a 1971 a a a b 1972 b ‘E a c c 1973 a g a b 197M a g ’ a b 1975 a a b a Numbers of Species Stations Years 1 2 3 h 5 1970 a a a a b 1971 g g a E c 1972 s s a 2 c 1973 g c a b c l97h a a a a b 1975 a a b b a Biomass Stations Years 1 2 3 h 5 1970 g a a b c 1971 a a a b b b C 1972 a a a a b 1973 a b a % c 197& a b a a c b C b 1975 a a b b a la,b,c, etc. . . Stations having the same small letter are not signi— cantly different from each other. 58 Table A3. Tukey's multiple range comparison test among years of the study for all species. Numbers of Individuals Spring Summer w. Fall Station 70 71 72 73 7h 75 7O 71 72 73 7h 75 7O 71 72 73 7b a a l a a a a a a b a a b a b a a a a a d a a a a 2 a a a b c c b b b a b b b a a a a 3 a a a a a a a a a a a b a a a a a b b h a a a b b g a a a b b a b b g c 5 a a a a a a c a a b a a a a a a a ____________________ E-E_E-E-___-__-__ Numbers of Species Spring, Summer Fall Station 70 71 72 73 7h 75 7o 71 72 73 7h 75 7o 71 72 73 7h 1 a a g a a b a a a a a b a a a a a a a a b 2 b a b b c c a a a a a a a a a a a 3 a a a a a a a a b a a c a a a a a b c b b h a a a a a a g a a a b b a b b a a 5 a a a a a a b a a a a a a a a a a ...................... E _ E _ E _ _ - _ - _ _ _ - - Biomass Spring Summer Fall Station 70 71 72 73 7h 75 7o 71 72 73 7h 75 7o 71 72 73 7h 1 a a 8. 8. B. 8. a 8. a a a a 8. 8. 8. 8. 8. 2 a a a a a b a a a a a a a a a a a 3 a a a a a a a a a a a a a a a a a h a a a a a a a b b b a a a b c a a 5 a a a a a a a a a a a a a a a a a l . . . . a,b,c, etc. . . Years hav1ng the same small letter are £93.51gn1f1cant1y different from each other. ‘Ill 171.51NnrJWImfl 59 Table Ah. Tukey's multiple range comparison test for yellow perch, carp, and goldfish.l Perch Spring Summer Fall Station 70 71 72 73 7“ 75 70 71 72 73 7h 75 70 71 72 73 7h 1 a a a a a g a a b b b a a a a a c a g 2 a a a b a a a a a a 2 d b a c d b b b b a a a a a a a a a a a a a b g a b b h a a a a a a b a a a a a b a a a - -5- _ E - E _ E _ E - E _ E _ E _ E - E - E - E - E _ E _ E - E - E - E Carp p§pringfi Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 7h 75 70 71 72 73 7h l a a a a a a a a a a a a a a a a a 2 a a a a a a a a a a a a a a a a a 3 a a a a a a a a a a a a a a a a a a. a h a a a a b b b a a a a a b b b b 5 a a a a a a a a a a a a a a a a a Goldfish Spring Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 7h 75 7o 71 72 73 7h l a a a a a a a a a a a a a a a a a 2 a a a a a a a a a a a a a a a a a a 3 a a a a a a b a a a b b a a a a a a a b h a a a b a a a b b a c a b b b c 5 a a a a a a a a a a a a a a a a a l . . . . a,b,c, etc. . . Years hav1ng the same small letter are not s1gn1f1cantly different from each other. 60 Table A5. Tukey's multiple range comparison test for gizzard shad, freshwater drum, and alewife. Gizzard Shad Spring Summer Fall Station 70 71 72 73 7h 75 7o 71 72 73 7h 75 70 71 72 73 7h 1 a a a a a a a a a a a a a a a a a a a 2 a a a a a a b a b a b a a a a a a 3 a a a a a a a a a a a a a a a a a a a a a a a h a a b b b a b a a b b b a a b b _ -5- _ E - E _ E _ E _ E _ E _ E _ E _ E _ E - E - E _ E _ E _ E _ E _ E Carp Spring Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 7h 75 70 71 72 73 7h 1 a a a a a a a a a a a b a a a a a b b b b a a a a a 2 a b b b b a a a a a a b b b b . a a a a 3 a a a a a a a b b b b a a a b a b a a a h a a a a a a a a a a a a a b b b b _ -5- - E - E - E _ E _ E _ E _ E _ E _ E - E - E _ E - E _ E _ E _ E _ E Alewife Spring Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 7h 75 7O 71 72 73 7h a a a l a a a b b b a a a a a a b b a a b a a 2 a a a a a a a a a a a a b b a a b 3 a a a a a a a a a a b a a a a a a b b h a a a a a a a a a a a a a a a a a 5 a a a a a a a a a a a a a a a a a l a,b,c, etc. . . Years having the same small letter are not significantly different from each other. 61 Table A6. Tukey's multiple range comparison test for white bass and emerald shiner. 1 White bass Spring Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 7h 75 7o 71 72 73 7b a a a l a a a a a a a b b b b a a a a a a 2 a a a a a a a a a a a a a a a a a 3 a a a a a a a a a a a a a a a a a h a a a a a a a a a a a a b a a a a a a 5 a a a a a a b a b b b b a a a a a Emerald shiner Spring Summer Fall Station 70 71 72 73 7h 75 70 71 72 73 Th 75 70 71 72 73 7h 1 a a a a a a a a a a a a a a a a a 2 a a a a b a a a a a a a a a a a a b b b 3 a a a a a a a a a a a a a a a a a h a a a a a a a a a a a a a a a a a 5 a a a a a a a a a a a a a a a a a 1 . . . . a,b,c, etc. . . Years hav1ng the same small letter are not Sign1f1cantly different from each other. ICHIGQN STQTE UNIV. LIBRRRIES |||l|l||| 74 050 W I!!! lllll III! II II 312 31027