HE UNIVERSITY OF MICHIGAN 

IMPINGEMENT LOSSES AT THE 

D. C. COOK NUCLEAR POWER PLANT 

OF FACTORS RESPONSIBLE AND 

POSSIBLE IMPACT ON LOCAL POPULATIONS 

DURING 1975-1982 WITH A DISCUSSION 

NANCY J. THURBER and DAVID .A JUDE 

. Special Report No. 115 of the 

Great Lakes Research Division 

Iri 
IMPINGEMENT LOSSES AT THE D. C. COOK NUCLEAR POWER Pk 

DURING 1975-1982 

WITX A DISCUSSION OF FACTORS RESPONSIBLE 

AND POSSIBLE IMPACT ON LOCAL POPULATIONS 

Nancy J. Thurber 

and 

David J. Jude 

Special Report No. 115 of the 

Great Lakes Research Division 

Great Lakes and Marine Waters Center 

The University of Michigan 

2200 Bonisteel Blvd. 

Ann Arbor, MI 48109 

1985 
TABLE OF CoNTEbITs 

LIST Cl? FIaJIZeS ............................................................ iv 

LIST OF .LEs ............................................................. v 

LIST OE' APPENDICES . .. ........................................................ Vll 

I.IO............................................................... 1 

M.IXS .................................................................... 2 

ReSULTS AND DI.SI. ..................................................... 5 

species CcII(pOsition ................................................... 5 

Seasonal Ab.a. .................................................... 45 

rSnpimpd Fish Canpared with Field-Cawht Fi. ......................... 52 

Plant Eff.tS ......................................................... 56 

Mitigative Measures for Impirganent ................................... 59 

S~Y .................................................................... 61 

.E ............................................................ 65 

LITERATURE CI. ........................................................... 67 
LIST OE' FIGURES 

2. Species canposition of the total nuaber of fish impiwej during 

spring (March, April, May) 1975-1982 at the D. C. Cook Plant, 

southeastern Lake Michigan. .......................................... 39 

3. Species composition of the total nunber of fish impinge during 

surmer (July, August, Septexber) 1975-1982 at the D. C. Cook Plant, 

southeastern Lake ~chigan........................................... 40 

4. Species camposition of the total nrraber of fish impinged each 

year during 19751982 at the D. C. Cook Plant, southeastern Lake 

Michigan............................................................. 41 

5. Species canpsition of the total nunber of fish collected in 

stadard-series fishing each year during 1975-1982 at the 

D. C. Cook Plant, southeastern Lake Michigan, ........................ 44 

6. Species camposition of the total nunber of fish impirged during 

fall (October, November) 19751982 at the D. C. Cook Plant, 

southeastern Lake ~c~gan........................................... 48 

7. Species cuaposition of the total nunber of fish impinged during 

winter (December, January, February) 19741982 at the D. C. Cook 

Plant, southeastern Lake Michigan. ................................... 49 

iv 
LIST OF TABLES 

Page 

1. Carmon and scientific names, and total estimated nunber of each 

species impinged during 1975-1982 at the D. C. Cook Nuclear 

Power Plant, southeastern Lake ~chigan............................... 6 

2. Nunber of fish impirged on the D. C. Cook Plant traveling screens 

during 1975.......... ................................................. 8 

3. Weight (kg) of fish impinged on the 0. C. Cook Plant traveling 

screens in 1975................ ....................................... 9 

4. Estimated nunber of fish impinged on the D. C. ,Cook Plant 

traveling screens in 1976..........................................e.. 10 

5. Estimated weight (kg) of fish impinged on the D. C. Cook Plant 

traveling screens in 1976...... ....................................... 11 

6. Estimated nu&= of fish impinged on the D. C. Cook Plant 

traveling screens in 1977....................... ...................... 12 

7. Estimated weight (kg) of fish impinged on the 0. C. Cook Plant 

traveling screens in 1977............................................. 13 

8. Estimated nunber of fish impiwed on the 0. C. Cook Plant 

traveling screns in 1978............................................. 14 

9. Estimated weight (kg) of fish impinged on the 0. C. Cook Plant 

traveling screens in 1978.................... ......................... 15 

10. Estimated nunber of fish impinged on the D. C. Cook Plant 

traveling screens in 1979 ............................................. 16 

11. Estimated weight (kg) of fish impinged on the D. C. Cook Plant 

travelixq screens in 1979. ............................................ 17 

12. Estimated nunber of fish impirged on the D. C. Cook Plant 

traveling screens in 1980............................................. 18 

13. Estimated weight (kg) of fish impinged on the D. C. Cook Plant 

traveling screens in 1980............................................. 19 

14. Estimated nunber of fish impixqed on the D. C. Cook Plant 

traveling screens in 1981...........................................-.. 20 

15. Estimated weight (kg) of fish impinged on the D. C. Cook Plant 

traveling screens in 1981 ............................................. 21 

16. Estimated nunber of fish impirqed on the D, C, Cook Plant 

traveling screens in 1982......... .................................... 22 
17. Estimated weight (kg) of fish impirged on the D. C. Cook Plant 

traveling screens in 1982............................................. 23 

18. Monthly water volme (in millions of cubic meters) punped through 

the condenser circulating water system of the Cook Plant, 

southeastern Lake Michigan fran 1975 to 1982. .......................... 26 

19. Number of fish caught by standard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1973.................................................... 27 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1974.................................................... 28 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Nichigan, 1975.............1...................................... 29 

and seining in D. C. Cook Plant study areas, southeastern 

20. Nunber of fish caught by standard series trawling, gillnetting, 

21. Nunber of fish caught by standard series trawling, gillnetting, 

22. Mnnber of fish caught by stardard series trawling, gillnetting, 

Lake Michigan, 1976. ................................................... 30 

23. Nuuber of fish caught by standard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1977.................................................... 31 

24. Nrmber of fish caught by stamiard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1978. ................................................... 32 

25. Nmkr of fish caught by standard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1979.................................................... 33 

26. Nudber of fish caught by stardard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1980. ................................................... 34 

27. Number of fish caught by standard series trawling, gillnetting, 

and seining in D. C. Cook Plant study areas, southeastern 

Lake Michigan, 1981.................................................... 35 

and seining in D. C. Cook Plant study areas, southeastern 

28. Nunber of fish caught by standard series trawling, gillnetting, 

Lake Michigan, 1982. ................................................... 36 

29. Iake Michigan water temperatures (C) measured at the St. Joseph 

Municipal Water Plant.................................................. 43 

30. A canparison between two periods of the percent change in volune 

of water pmped and nunber of fish impiqed annually at the 

D. C. Cook Plant....................................................... 57 

vi 
Apperdix Page 

1. Lake Michigan water temperatures recorded daily at the St. Joseph 

municipal water plant during 1975.................................... A-1 

2. Lake Michigan water temperatures recorded daily at the St. Joseph 

municipal water plant during 1976.................................... A-2 

3. Lake Michigan water temperatures recorded daily at the St. Joseph 

municipal water plant during 1977.........,.......................... A-3 

4. Lake Michigan water tempratures recorded daily at the St. Joseph 

municipal water plant during 1978.................................... A-4 

5. Lake Michigan water temperatures recorded daily at the St. Joseph 

municipal water plant during 1979.................................... A-5 

6. Lake Michigan water temperatures recorded daily at the St. Joseph 

municipal water plant during 1980.................................... A-6 

7. Lake Michigan water tanperatures recorded 'daily at the St. Joseph 

8, Lake Michigan water temperatures recorded daily at the St. Joseph 

9. Length-frequency histogram of alewives impinged during 1975 

municipal water plant during 1981.................................... A-7 

municipal water plant during 1982.................................... A-8 

at the Cook Plant, southeastern hke Michigan.................. ...... A-9 

10. Length-frequency histograms of alewives caught during 1975 field 

sampling at the Cook Plant, southeastern hke Michigan. . . . . . . . .. . . . . .A-10 

11. Length-frequency histograms of alewives impinged during 1976 

at the Cook Plant, southeastern Lake Michigan........ .............. ..A-ll 

12. Length-frequency histograms of alewives caught during 1976 field 

sampling at the Cook Plant, southeastern Lake Michigan....... ........ A-12 

13. Length-frequency histograms of alewives impinged during 1977 

at the Cook Plant, southeastern Lake Michigan...... .................. A-13 

14. Length-frequency histograms of alewives caught during 1977 field 

sampling at the Cook Plant, southeastern Lake Michigan........ .... ...A-14 

15. Length-frequency histograms of alewives impinged during 1978 

at the Cook Plant, southeastern Lake Michigan. . . . . . . . . . . . . . . . . . . . . .A-15 

16. Length-frequency histograms of alewives caught during 1978 field 

sampling at the Cook Plant, southeastern Lake Michig an............... A-16 

vi i 
17. -*-frequency histograms of alewives impinged during 1979 

at the Cook Plant, southeastern Lake ~chigan........................A-17 

18. kngth-frequency histogrms of alewives caught during 1979 field 

sampling at the Cook Plant, southeastern Lake Michigan..........,....A-l8 

19. mth-frequency histograms of alewives impinged during 1980 

at the Cook Plant, southeastern Lake Michigan. , . . . . . . . . . . . . . . . . . . . . . .A-19 * 

20. bngth-frequency histograms of alewives caught during 1980 field 

sampling at the Cook Plant, southeastem Lake Michigan.............,.A-20 

21. qth-frequency histograms of alewives impinged during 1981 

at the Cook Plant, southeastern Lake Michigan.............,...,,....,A-21 

22. Length-frequency histograms of alewives caught during 1981 field 

sampling at the Cook Plant, southeastern Lake Michigan, . . . . . . . . , . . . . .A-22 

23. Length-frequency histograms of alewives impinge3 during 1982 

24. Lengtfi-frequeq histograms of alewives caught during 1982 field 

25. Letqth-frequency histograms of spottail shiners impinged during 

c at the Cook Plant, southeistern Lake Michigan. . . . . . . . . . . . . . . . . . . . . . .A-23 

sampling at the Cook Plant, southeastern Lake Michigan.....,..,......A-24 

1975 at the Cook Plant, southeastern Lake Michigan...................A-25 

26. Length-frequency histograms of spottail shiners caught during 1975 

27. Length-frequency histograms of spottail shiners impinged during 

field sampling at the Cook Plant, Southeastern Lake Michigan.........A-26 

1976 at the Cook Plant, southeastern Lake Michigan...............,...A-27 

28. Length-frequency histograms of spottail shiners caught during 1976 

field sanpling at the Cook Plant, southeastern Lake Michigan.........A-28 

29. Length-frequency histograms of spottail shiners impinged during 

1977 at the Cook Plant, southeastern Lake Michigan...... ............. A-29 

30. Length-frequency histograw of spottail shiners caught during 1977 

31. Length-frequency histograms of spottail shiners impinged during 

field sampling at the Cook Plant, southeastern Lake Michigan......,..A-30 

1978 at the Cook Plant, mutheastern Lake Michigan.. ................. A-31 

32. Length-frequency histograms of spottail shiners caught during 1978 

33. Length-frequency histograms of spottail shiners impinged during 

34. Length-frequency histograms of spottail shiners caught during 1979 

field sanpling at the Cook Plant, southeastern Lake Michigan,. ....... A-32 

1979 at the Cook Plant, southeastern Lake Michigan ...................A-33 

field sampling at the Cook Plant, southeastern Lake Michigan..... .... A-34 

viii 
35. Length-frequency histograms of spottail shiners impinged during 

1980 at the Cook Plant, southeastern Lake Michigan.... ............... A-35 

36. Length-frequency histograms of spottail shiners caught during 1980 

field sampling at the Cook Plant, southeastern Lake Michig an......... A-36 

37. Length-frequency histograms of spottail shiners impinged during 

38. Iength-frquency histograms of spottail shiners caGht during 1981 

1981 at the Cook Plant, southeastern Lake Michigan.... ............... A-37 

field smpling at the Cook Plant, southeastern Lake Michigan.........A-38 

39. Length-frequency histograns of spottail shiners impinged during 

1982 at the Cook Plant, southeastern Lake Michigan...................A-39 

40. Length-frequency histograms of spottail shiners caught during 1982 

field sampling at the Cook Plant, southeastern Lake Michigan.........A-40 

41. Length-frequency histograms of trout-perch impinged during 1975 

42. Length-frequency histograms of trout-perch caught during 1975 field 

at the Cook Plant, Southeastern Lake Michigan.................. ......A-41 

sampling at the Cook Plant, southeastern Lake Michigan...............A-42 

43. Length-frequency histograms of trout-perch impinged during 1976 

at the Cook Plant, I southeastern Lake Michigan.. . . . . . . . . . . . . . . . . . . . . . .A-43 

44. Length-frequency histograms of trout-perch caught during 1976 field 

45. Length-frequency histograms of trout-perch impinged during 1977 

samplirrg at the Cook Plant, southeastern Lake Michigan...............A-44 

at the Cook Plant, southeastern Lake Michigan. . . . . . . . . . . . . . . . . . . . . . .A-45 

46. Length-frequency histograms of trout-perch caught during 1977 field 

47. Length-frequency histograms of trout-perch impinged during 1978 

smpling at the Cook Plant, southeastern Lake Michigan.... ........ ...A-46 

at the Cook Plant, southeastern Lake Michigan. . . . . . . . . . . . . . . . . . . . . . . .A-47 

48. Length-frequency histograms of trout-perch caught during 1978 field 

sampling at the Cook Plant, southeastern Lake Michigan.... ........ ...A-48 

49. Length-frequency histograms of trout-perch impinged during 1979 

at the Cook Plant, southeastern Lake Michigan.............. .......... A-49 

50. Leng~-frequency histograms of trout-perch caught during 1979 field 

sampling at the Cook Plant, southeastern Lake Michigan......... .... ..A-SO 

51. Length-frequency histograms of trout-perch impinge3 during 1980 

at the Cook Plant, southeastern Lake Michigan.. . . . . . . . . . . . . . . . . . . . . . .A-51 

52. Length-frequency histograms of trout-perch caught during 1980 field 

sampling at the Cook Plant, southeastern Lake Michigan.. .. ...... ... . .A-52 

ix 
53. mgth-frequency histograms of trout-perch impinged during 1981 

at the Cook Plant, southeastern Lake Michigan............ ............A-53 

54. kngth-frequency histograms of trout-perch caught during 1981 field 

sampling at the Cook Plant, southeastern Lake Michigan. . . . . . . . ... . . . .A-54 

55. Length-frequency histograms of trout-perch impinged during 1982 . at the Cook Plant, southeastern Lake Michigan.. . . . . . . . . . . . . . . . . . . . . . .A45 

56. Length-frequency histograms of trout-perch caught during 1982 field 

-ling at the Cook Plant, Southeastern Lake Michigan...............A-56 

57. Length-frequency histograms of yellow perch impinged during 1975 

at the Cook Plant, southeastern Lake Michigan........................A-57 

58. Length-frequency histograms of yellow perch caqht during 1975 field 

-ling at the Cook Plant, southeastern Lake Michigan...............A-58 

59. Length-frequency histograms of yellow perch impinged during 1976 

at the Cook Plant, soutkastem Lake Mi~igan........................A-59 

60. Length-frequency histograms of yellow perch caught during 1976 field 

sampling at the Cook Plant, southeastern Lake Michigan...,...........A-60 

61. Length-frequency histograms of yellow perch impinged during 1977 

at the Cook Plant, southeaste-m Lake Michigan.,......................A-61 

62. Length-frequency histograms of yellow perch caught during 1977 field 

sanpling at the Cook Plant, southeastern Lake Michigan...............A-62 

63. Length-frequency histqrams of yellow perch impinged during 1978 

64. Length-frequency histograms of yellow perch caught during 1978 field 

at the Cook Plant, southeastern Lake Michigan........................A-63 

sanpling at the Cook Plant, southeastern Lake Michigan...............A-64 

65. Length-frequency histograms of yellow perch irnpiwd during 1979 

66. Length-frequency histograms of yellow perch caught during 1979 field 

at the Cook Plant, southeastern Lake Michigan.....,..................A-65 

sampling at the Cook Plant, southeastern Lake Michigan...............A-66 

67. Length-frequency histograms of yellow perch impingd during 1980 

at the Cook Plant, southeastern Lake ~chigan........................A-67 

68. Length-frequency histograms of yellow perch caught during 1980 field 

69. Length-frequency histograms of yellow perch impinged during 1981 

sanpling at the Cook Plant, southeastern Lake Michigan...............A-68 

at the Cook Plant, southeastern Lake Michig an........................ A-69 

70. Lewth-frequency histograms of yellow perch caught during 1981 field 

sampling at the Cook Plant, southeastern Lake Michig an............... A-70 

X 
71. kngth-frequency histograms of yellow perch impinge3 during 1982 

at the Cook Plant, southeastern Lake Michigan................., ...... A-71 

72. kngtbfrequency histograms of yellow perch caught during 1982 field 

sanplirq at the Cook Plant, southeastern Lake Michigan.......... ..... A-72 

73. Length-frequency histograms of rainbow melt impinged during 1975 

at the Cook Plant, southeastern Lake Michigan. ...................... .A-73 

74. Lmgth-frequency histograms of rainbow melt caught during 1975 

field sampling at the Cook Plant, southeastern Lake Michigan.... ..... A-74 

75. mth-frequency histograms of rainbow melt impinged during 1976 

at the Cook Plant, southeastern Lake Michigan.. ..................... .A-75 . 

76. Length-frequency histograms of rainbow melt caught during 1976 

field sampling at the Cook Plant, southeastern Lake Michigan.........A-76 

77. Length-frequency histograms of rainbow melt impinged during 1977 

at the Cook Plant, southeastern Lake Michig an........................ A-77 

78. Length-frequency histograms of rainbow melt caught during 1977 

field sanpling at the Cook Plant, southeastern Lake Michig an......... A-78 

79. Length-frequency histograms of rainbow melt impinged during 1978 

at the Cook Plant, Southeastern Lake Michigan............~..... ...... A-79 

80. Length-frequency histograms of rainbow melt caught during 1978 

field sampling at the Cook Plant, southeastern Lake Michigan. ........ A-80 

81. Length-frequency histograms of rainbow melt impingd during 1979 

at the Cook Plant, southeastern Lake Michigan.................. ......~- 81 

82. Length-frequency histograms of rainbow melt caught during 1979 

field sampling at the Cook Plant, southeastern Lake Michigan,.... .... A-82 

83. Length-frequency histograms of rainbow melt impinge3 during 1980 

at the Cook Plant, southeastern Lake Michigan........ ................ A-83 

84. Length-frequency histograms of rainbow melt caught during 1980 

field sampling at the Cook Plant, southeastern Lake Michigan. ........ A-84 

85. Length-frequency histograms of rainbow melt impinged during 1981 

at the Cook Plant, southeastern Lake Michigan....... ................. A-85 

86. Length-frequency histograms of rainbow melt caught during 1981 

field sanpling at the Cook Plant, southeastern Lake Michig an......... A-86 

87. Length-frequency histograms of rainbow smelt impinged during 1982 

88. Length-frequency histograms of rainbow melt caught during 1982 

at the Cook Plant, southeastern Lake Michigan ........................ A-87 

field samplillg at the Cook Plant, southeastern Lake Michigan ......... A-88 

xi 
INTRODUCTION 

The Donald C. Cook Nuclear Power Plant 1s a 2,200 My utility on the 

southeastern shore of Lake Michigan near Bridgman, Michigan. Unit 1 (1,100 

MU), which began operation in 1975, requires 2.7 x 10 liters/- cooling 6 

6 water, while Unit 2, also 1,100 Mu, uses 3.6 x 10 liters/min. Though Unit 2 

began operation in 1978, sustained pumping for a month or longer at full 

capacity did not occur until 1979. 

cribs located 686 m offshore fn 7.3 m of water, and heated water (with a 

calculated maximum AT of 12.1°C) is discharged through two slot-jet discharge 

structures located 366 m offshore in 5.5 m of watet. With two units 

operating, water velocity at the intake crib is 0.4 m/s. mximm water 

velocity is 1.8 m/s within the intake pipe. To prevat erosion and scour, 

a riprap bed (approximately 6 ha) of crushed limestone 0.1-1.0 m in diameter 

was deposited around the intake and discharge structures during plant 

construction. 

Cooling water enters through three intake 

Within the screenhouse, trash bars 6.6 an apart prevent large debris from 

entering the forebay. Within the forebay, vertical traveling screens impinge 

trash and fish too large to pass through the 9.5-pilm-bar mesh screens. 

organisms (mostly fish larvae and eggs, and zooplankton) are entrained with 

the cooling water and pass through the condensers. 

"impingement" and "entrainment," "entrapment" in this report refers to fish 

entering the forebay through the intakes. 

entrapment because of the possibility that not all fish which enter the 

forebay are eventually impinged. To summarize, entrainment refers to those 

organisms present in the cooling water that pass through the traveling screens 

Smaller 

In addition to the terms 

Impingement is distinguished from 

1 
and condensers, and are discharged back into the lake. All fish which enter 

the forebay and cannot pass through the traveling screens are considered to be 

entrapped. 

is considered impinged when it is caught on the intake vertical traveling 

screens and sluiced into plant trash baskets. 

Some entrapped fish may make their way back to the lake. A fish 

This report contains annual estimates and species composition of fish 

impinged at the 0. C. Cook Plant and c-es thrm with similar data for 

field-caught fish for 1980-1982. Also discussed are smasonal and yearly 

trends in fish abundance and anviromental and plant opuation effects on 

rates of fish impingement. 

discusses similar results from 1975-1979. 

A previous report (!Churber and Jude 1984) 

METHODS 

Fish and debris from the traveling screms were reparatd by Cook Plant 

personnel. All fish were bagged, labeled with date and time, and than frozen. 

University of Michigan personnel collected and weighad all frozen fish; a 24-h 

sample was savad every fourth day anb sorted by species and size. When many 

fish of the sam size were collected in fourth-day samples, a subsample 

composed of up to 30 fish war randomly selected and romafning fish were 

weighed and discarded. All savad fish were measured to the nearest millimeter 

(total length), weighed to the nearest gram, and sexed; stomachs were examined 

for presence of food. 

damgo were also recordd. 

Condition of gonads, presence of disaasa, or physical 

Fourth-day samples (number and weight of fish) and weight of all fish 

impinged on interim days were used to estimate total monthly Fmpingament 

2 
losses by species. 

samples was used to partition the actual monthly weight of fish impinged into 

weight estimates by species, according to the formula: 

Percent species composition (by weight) of fourth-day 

where : 

= Estimated monthly weight of fish impinged for a given species; EW 

e Monthly weight of Fourth-day impingement samples for a given sW 

pW 

TW 

species ; 

= Monthly weight of fourth-day impingement samples, all fish combined; 

and 

- Total monthly weight of all fish impinged (includes fourth-day and 

interim days). 

* Number of fish impinged per mOnth was then estimated using 

where: 

En = Estimated total number of fish impinged each month for a given 

species; and 

= Mean weight per fish of a given species, calculated for each species 

from number and weight of fish of each species impinged in fourth-bay samples 

for a given month. 

Offshore standard-series field samples were collected by gill net and 

bottom trawl from four stations: 

6-m and 9-m stations at Warren Dunes State Park, about 11 km south of the Cook 

6-m and 9-m stations at the Cook Plant and 

3 
Plant. Fish were seined from the beach zone at two stations near the Cook 

Plant (one north and one south of the plant), and at one station at Warren 

Dunes State Park. 

Gill nets 160 x 1.8 m were set at offshore stations once per month for 

approxhately 12 h during daylight and 12 h during the night. 

adjusted to catch par 12 h to standardize data (Jude et al. 1979). 

composed of 12 panels of netting as follows: 

following mesh sizes (bar measure) - 1.3 cm, 1.9 cm, and 2.5 cm; 15.2-m 

sections of mesh sizes 3.2-7.6 cm by 0.6-cm intenmls; and a finallS.2-m 

section of 10-cm mesh. 

bottom. 

Catch was 

Nets were 

7.6-m sections of each of the 

All gill nets were set parallel to shore on the 

Duplicate, 1O-min bottan tows were taken monthly both day and night at 

offshore stations, using a semi-balloon, nylon trawl having a 4.9-m haadrope 

and a 5.8-m tootrope. The body and cod end wee canposed respectively of 1.9- 

cm and 1.6-cm bar mesh, while tha cod and intulinu was 0.7-cm bar mesh. All 

trawl hauls were made at an average speed of 5 km/h, i.e., at a fixed rppl 

using the University of Michigan's R/V MYSIS. The trawl was towed parallel to 

shore following the 6- or 9-m depth contours; one haul was taken north to 

south and the other south to north at each depth contour. 

Beach seining was usually conducted during periods of reduced wave height 

using a nylon seine 38 x 1.8 m with a 1.8 x 1.8- bag; the entire seine had 

0.64-cm bar mesh. The seine was first stretchd perpMdfcular to the 

shoreline and then pulled parallel to shore a distance of 61 m. Duplicate, 

non-overlapping samples were taken in this mannet both day and night once each 

month at beach stations. The seine was pulled against the current or 

4 
southerly when no current was detectable. 

the seine against the current, seining was done with the current. 

When it was too difficult to pull 

Field-caught fish were processed in the same manner as impinged fish. 

For a more detailed discussion of field-sampling methods, see Jude et al. 

(19791, Tesar et al. (19851, and Tesar and Jude (1985). Common and scientific 

names of fish discussed in this paper are presented in Table 1. 

RESULTS AND DISCUSSION 

SPECIES COMPOSITION 

The number of fish impinged annually at the Cook Plant during 1975-1982 

ranged from 53,190 (1,833.34 kg) fish in 1977 to 2,307,654 (71,208.81 kg) fish 

in 1980 (Tables 2-17). Percent contributions that each species made to each 

year's total catch were averaged for 1975-1982; the fish mOst often impinged 

was the alewife (68% of total catch). Following in order of abundance were 

spottail shiner (1021, yellow perch (9%), trout-perch (5%), rainbow smelt 

(4%), and slimy sculpin (2%). Though averaging less than 1% over all years, 

bloaters increased in nlmrber during the study period and ranged from 0.02 to 

4% of each year's total. None of the other less c~lpmon species ever 

constituted more than 0.9% of the total number of fish impinged in any 1 year 

during 1975-1982 (Tables 2-17). 

in highest numbers, rank order of the other species varied from year to year. 

During 1975-1982, 61 species weze impinged (Tables 2-17). Nineteen species 

were impinged every year for all 8 years of the study, while 22 species were 

impinged during 4 years or less and were considered rare. 

Except for alewife, which was always impinged 

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In genecal, species composition of impinged fish reflected fish abundance 

in the nearshore area (<lo-m depth) tempered by the unique vulnerability of 

certain species to the impingement process. Differences in species 

composition among years could usually be attributed to fluctuations in year- . 

class strength among the most abundant species, or seasonal differences in 

periods of maximum or minimum pumping levels. 

Because both units were operating during 1978-1982, these years should be 

considered separately from 1975 to 1977 when only one unit was operating. An 

overview of the data (Fig. 1) shows that during one-unit operation, 1975-1977, 

impingemurt of alewives was around 100,000 fish (Tables 2, 4, 61, and volume 

of cooling watar pumped through the plant was also consistent, around 

1.2 x 10 m /yr (Table 18). During these years, alewife populations in the 

lake fluctuated according to our index data, frm about 42,000 fish in 

standard series catches in 1975, to 137,000 in 1976, and back to 56,000 in 

1977 (Tables 19-28). Thus, it appear& that although alewife populations 

varied a great deal in Lake Michigan, these variations did not increase 

impingement substantially during 1976 when alewife abundance was highest of 

the 3 years in Lake Michigan. 

93 

All variables changed in the next 5 years of operation (1978-1982) as 

93 Unit 2 doubled plant prcpaping rates from around 1.2 x 10 m /yr to 2.3- 

2.8 x 10 m /yr (Table 18). Alewife populations in the lake exhibited a 

catastrophic dacline starting in 1980 (Tables 21-28), while iarphgement rates 

increased dramatically in the 1980s (Tables 2-17). 

causal mechanisms is difficult because of the many Varying factors. 

For example, even though total volume of cooling water increased'twofold from 

1977 to 1978, impingement losses did not rise proportionally. 

93 

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36 
anomaly can be partially explained by low pumping rates during April and by 

1978, which is the usual time of maximum impingement of alewife. These low 

pumping rates in the spring thus led to substantially reduced total 

impingement losses in 1978 when compared to other years of two-unit operation 

when spring pumping rates were "average" during this period. A second example 

of the difficulty in explaining changes is related to physical conditions in 

the lake (water temperature, storms, currents) interacting with the differing 

behaviors of age-groups of alewives (Appendixes lo, 12, 14, 16, 18, 20, 22, 

24). 

decline in populations of alewife in Lake Michigan (Jude and Tesar 1985). 

However, a different group of fish in a different month in each of the 3 years 

The peak years of impingement, 1980-1982, occurred in spite of a general ---_ - -------- - - 

c__ 

____L-- IIs_lll.__l.ll- 

-------- 

was responsible for a substantial proportion of total numbers and biomass of 

fish impinged in each of the 3 years. In 1980, large numbers of adults--w-s-e. -2 

L& *--" I--.--LII---^-- 1_(---___.._-- " ~- 

i# A bw 

impinged in April-May (Appendix 191, in 1981, yearlings impinged during May- 

_____________I_-------- 

June (Appendix 21) was the dauinant group in total losses, while for 1982, 

- 

yearlings and adults impinged in June (Appendix 23) comprised the highest 

fraction of losses. t 

Therefore, it appeared that physical factors which resulted in -...---...-- Il..-----_II_I---^----- ,. 

concentrating certain age-groups of alewives or making them more susceptible 

to impinganent because of high pumping rates during these periods of 

susceptibility could explain much of the variability in impingement rates 

observed. Alewives illustrate at least two of these conditions. As nearshore 

water warms during spring, fish follow the warm-water mass and concentrate 

near shore (Wells 1968, Jude et al. 1979, Tesar and Jude 1985). 

*Ir __-I-- __-------_ I_ 1 - -. ----- ___I 

-__1_ I-?.) 

I ------_lll. 

L.- --- - -- - ~ -- - ___ - 

If the plant -+- _- - -_I-_ 

%i 

i 

operates at or near __l.__II_xIIII ___^_ 

capacity __ and without substantial - .- interruption _l_l__.__._ during April - - 

and May, large numbers of fish of many species are impinged, but alewives -=----__.-,----,____I"___ . , .. - . .. .. .- .... . .... ..,-.. -- --- - 

37 
dominate the loss. This was the case in 1975 (one-unit operational) and 1980 

(both units operational) (Tables 2, 12); during both years alewives accounted 

fir over 759 of the total impingement loss (Fig. 2). 

were similar during 1978 and 1980 (2.4 x 10 vs. 2.8 x 10 m 1; however, 

volume pumped during April-y 1978 was low, while in 1980 it was high (Table 

18). 

alewife losses (0.2 million) cwpard with 1980 (1.8 million) evm though 

pumping volumes for the year were camparable and alewife populations in Lake 

Michigan had declined over that period. 

occurred among species c~mp~n in nearshore watu during late sumnu through 

autumn, particularly spottail shiner, rainbow smelt, and trout-perch (Fig. 3). 

Despite the declining populations of alewivos in Lake Michigan during the I____ -_-_ I_IIIc -- - ____Ix_-_ I I - 

1980s, alewives __--I-- continued to be impingd in large quantities, and they even- ____- ”------- - - --- -_I- ---- - --- 

began to comprise a larger fraction of impingamsnt losses over this period 

(1980-1982) compard with the earlier years, 3975-1979 (Fig. 4). Clupeids, in 

general, may be particularly vulnerable to ipppfnganent. 

throughout Lake Michigan, alewives were the most oft- impingd species (Benda 

and Gulvas 1976, Sharma and Freanan 19771, while gizzard shad were most often 

impingd at plants in southun Lake Huron and Lake Erie (Be and Routcooper 

1976, Eisele and Malaric 1977). Gizzard shad and threadfin shad were the most 

often impingd fish at powu plants on southem reservoirs and estuaries 

(Freeman and Sharma 1977, Loar et al. 1977). 

Yearly pumping volumes 

9 93 

The reduced flow in spring 1978 resulted in considerably lower total 

High impingement losses in 1978 

1_________^_--- -” 

_I_--- __ At water intakes *--------- I_ I---- __ L__ - ‘ t.^--.o--- 

By 1980, both units were operating at full capacity for axtended periods 

of time. Volume of cooling water pumped annually during 1980-1982 was notably 

higher than during any previous 

(Table 18). Beside t??e decline 

93 

year and leveled off around 2.7 x 10 m /yr 

in alewife populations, there were a few other 
60- 

d 

7 

3 

m 

a 40- 

W 

> - 

J 20- W 

1975 

n 

1976 

n 

1977 1978 

n 

1979 1980 1981 1982 

Figure 2. 

impinged during spring (March, April, May) 1975-1982 at the D. C. 

cook Plant, southeastern Lake Michigan. 

months of steadily rising water temperature. 

Species composition of the total number of fish 

Spring was defined as 

39 
%loo60- 4 

in’ 

40- 

n 

i 20- 

a 

W 

1975 1976 1977 1978 1979 1980 1981 1982 

Figure 3. Species composition of the total number of fish 

impinged during summer (July, August, September) 1975-1982 at the 

D. C. Cook Plant, southeastern Lake Michigan. Summer was defined 

as months of maximum average temperature. 

40 
Lr, 

LL 

0 

a 40 

20 W 

a 

H 

n n n n 

3 1979 I980 1981 I 1982 

Figure 4. 

impinged each year during 1975-1982 at the D. C. Cook Plant, 

southeastern Lake Michigan. 

Species composition of the total number of fish 

41 
notable shifts in species composition of fish impinged during these years that 

were more closely related to fish population changes in the lake than to 

changes in cooling water flows. In 1980 and 1981, there was more than a 

twofold increase in number of yellow perch wingad annually (Fig. 4), 

probably reflecting the increasing abundance of yellow perch as alewife, a 

suspected predator of yellow perch larvae, declined (Pig. 5, Tables 19-28; 

Jude and Tesar 1985). Rainbow malt populations also increased during the 

-I___. _cI 

---w __I------ - -_b__- 

- - - - 

early 1980s in _l_l response to the - --.----- alewife decline, - and rainbow smelt were also _.____L.- 

impinged in dramatically higher numbers during 1980-1981than during earlier 

years (Pig. 4, Table 11, as well as being abundant in field catches (Fig. 5, 

Tables 19-28). 

During 1975-1979 (one unit operation), an average of 160 salmonids was 

impingd annually. 

these years. An average of over 1,000 salmonids was impinged annually over 

1980-1982 (Tables 12, 14, 16). Most of these fish were juvenile chinook 

Lak8 trout was the most camonly impinged salmonid during 

salmon (875 - probably nmly planted) in 1980, adult and juvenile lake trout 

(517 fish) in 1981, and adult coho salmon (530 fish) in 1982. 

mingernurt losses for most species declind during 1982, mOst notably 

for rainbow smelt, trout-perch, and bloaters. Lake-wid8 populatfon 

f luctwtfons may have b.m partially responsible (Jude and Tesar 1985) , but 

much of the decline in number of fish impinged can probably be attributed to 

local water teqmratur8s, which were unusually warm during July-September 1982 

(Table 29). 

(Appendixes 1-8), the thermcline was relatively stable and intersected the 

Because thu8 was only one notable upwelling during this time . 

bottom far offshore. Many species concentrate at or near the thermocline - _____- - --- , -__-_____ - 

42 
Table-29. Lake Michigan water temperatures (C) measured 

at the St. Joseph Municipal Water Plant; intake depth - 

5.8 m. Data are monthly means of the daily average of 

maximum and minimum temperatures. 

Month 

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1973- 

1982 

0.5 

1.2 

1.3 

1.1 

1.1 

1.7 

1.3 

3.0 

0.9 

1.2 

1.3 

0.6 

1.1 

1.1 

2.1 

1.1 

1.4 

1.8 

2.4 

1.2 

0.7 

1.4 

4.2 7.1 10.6 17.9 18.8 19.7 16.4 15.7 9.7 4.1 

3.7 7.5 11.3 14.9 17.2 16.5 16.2 13.3 9.2 3.0 

2.1 5.4 10.9 16.2 19.5 15.5 17.3 14.5 10.9 4.1 

5.4 9.6 11.0 16.7 19.2 20.5 18.0 14.6 8.3 2.0 

3.5 8.7 12.4 14.7 18.6 18.5 15.9 12.1 8.5 2.5 

1.5 5.6 10.2 13.7 14.1 17.9 18.4 14.0 10.1 3.1 

2.6 6.6 10.6 14.1 18.0 19.5 17.3 14.5 10.3 5.4 

2.4 5.9 9.8 14.3 16.7 16.4 15.2 12.4 7.2 2.6 

3.2 8.2 9.8 15.4 14.8 19.2 18.2 12.0 8.5 3.6 

1.8 6.3 10.7 13.7 18.5 20.1 18.5 14.4 8.9 5.8 

3.0 7.1 10.7 15.1 17.6 18.4 17.2 13.8 9.2 3.6 

43 
3 60 

n 

a 40 

W 

> 

120 W 

a 

d 

n 

1978 

1 I98 I 

n 

I 1982 

Figs-e 5. Species composition of the total number of fish 

collected in standard-series fishing each year during 1975-1982 

at the D. C. Cook Plant, southeastern Lake-Michigan.- 

44 
(Brandt 1980, Brandt et al. 19801, and thus were probably concentrated at 

depths greater than the intake depth during the late surmer months of 1982. 

___-___- - 

II -* ^^ __^__-__I __I -- - _I___ 

Over a period of several days in May 1980, more than half of the alewives 

‘appeared to have been dead before they were impinged. These fish are easily 

distinguished from fish that were alive when impinged for three reasons. They 

are emaciated, the scales and skin grayish and dull, and many are limp and 

compressed. In contrast, newly impinged fish are often alive when they enter 

the trash baskets, and most samples are placed in freezers within 5-6 hr of 

being impinged, thus preserving their color and form. Alewives which were 

already dead appeared in impingement samples immediately following unusually 

high impingement rates in April and May 1980. Because there was no 

corresponding increase in the numbet of dead alewives washed up on the beach 

or collected in our May field sanples, the impinged alewives probably died in 

the forebay from starvation and stress caused by wercrowdfng. 

During 1981 and 1982, both dead fish and debris from all impingement 

samples processed in the lab were weighed and recorded. There was no 

recurrence of the high proportion of dead fish that appeared in 1980. Of the 

total weight of impinged fish samples in both 1981 and 1982, weight of dead 

fish was about 12. 

samples in 1981 and 2% in 1982. 

Trash weight equaled 32 of the weight of impinged fish 

SEASONAL ABUNDANCE 

Number of fish impinged per month at the Cook Plant varied seasonally 

(Tables 2-17). 

impinged during winter. 

Most fish were impinged during April through October; few were 

Each year was characterized by a month of peak 
impingwent during June or July, and often another (usually secondary) pa in 

spring (April, May) or fall (September-November). 

Though factors influencing impingement overlapped over seasons and yeats, 

the dynamics contributing to heavy impingement losses differed fran season. to 

season. During spring, many fish are impinged as they move shoreward seeking 

warm water. Warming of Lake Michigan water during April is characterized by a 

narrow band of warmer, inshore water, separate and distinct from colder, 

offshore water. Forrpation of a pronounced and persistent thstmdl bar 

separating inshore and offshore water masses (Huang 1969, Mortimer 1973), may ' 

act as a barrier, concentrating fish in a narrow band of warm, nutrient-rich 

water close to. shore. A therm1 bar was present within 2 or 3 km of shore 

during periods of high impingement losses in April 1975 and 1980. High fish 

impingemat rates during this time may have resulted from increased activity 

and movement of fish and higher densities of fish inshore. 

In June and July, impingement losses may be quite high as fish mova 

shoreward to spawn. Among the more abundant species, alewife, spottail 

shiner, yellow perch, and trout-perch spawn during these months. Numbers of 

fish impinged during these months may also k strongly influenced by 

upwelling, which increases fish activity and causes my fish to move 

shoreward seeking preferred warmer temperature (Wells 1968, Emery 1970, Jude 

et al. 1979). Rainbow smelt and bloater, which prefer cold water (Wells 1968, 

Jude et al. 19791, may accompany cold, upwelled water inshore. Exceptionally 

high inpinganent losses during July 1978 coincided with three periods of 

strong upwelling (Appendfr 41, while in contrast during summer 1982 a low 

frequency of upwelling resulted in low impingement losses. Autumn impingement 

losses may be attributable to increased movement of fish as water temperatures 

46 
become isothermal and fish me offshore toward deeper water. In addition, 

impingement of large numbers of young-of-the-year (YOY) fish occurs as they 

attain a size which can be retained by traveling screens. 

Species composition of impingement losses also changed seasonally 

(Figs. 2, 3, 6, 7). This was particularly notable for alewives, which 

comprised over 801 of spring losses, nearly 601 of summer losses, about 251 of 

fall losses, and about 8% of winter losses. 

impingement losses was YOY and yearling yellow patch; trout-perch were also 

common in collections. Though winter impingement losses were low, spottail 

shiner, yellow perch, and rainbow smelt were all impinged frequently; 

evidently these species remain nearshore or forage frequently nearshore during 

winter. 

The largest component of autumn 

*g The biology of indiiridual species is an important factor determCrun 

seasonal patterns in impingement rates. The preference of alewives for warm 

water accounts for their high density inshore. Peak impingement of alewives 

usually occurred during June or July, when alewives moved inshore to spawn. 

In late SUPPPBT or autumn there was an increase in impingement of YOY alewives, 

which by this time were large enough (250 m) to be retained by traveling 

screens (Appendices 9, 11, 13, 15, 17, 19, 21). 

Spottail shiner preference for shallow depths and warm water (Wells 1968, 

Jude et al. 1979) affected spottail shiner impingement rates. 

spottail shiners increased in March and April as spottail shiners moved 

shoreward seeking warmer, inshore water. 

impingement of spottail shiners during May and June was low (Tables 2-17); 

field data indicated spottail shiners were mostly inshore of the intake depth 

(9 m) (Tesar et al. 1985, Tesar and Jude 1985). 

Impingement of 

Except for 1980 and 1981, 

Impinged spottail shiners 

$7 
5100 - 

LL 

LL 

0 

n 80 U 8 

W 

0 

Q 

z 

3 

5 60 

m 

a 40 

W 

> - 

G 

a 

20 

B 

n 

1975 1976 

m 

n 

1977 1978 1979 1980 1981 

n 

I982 

Figure 6. Species composition of the total number of fish 

impinged during fall (October, November) 1975-1982 at the D. C. 

Cook Plant, southeastern Lake Michigan. Fall was defined as 

months of steadily falling water temperature. 
.. 

w 

$! a 60 

n 

m 

a 40 

7 

3 

W 

> 

I- 

- 

a 

J 20 W 

N LL 

1975 1976 1977 1978 1979 1980 1981 1982 

Figure 7. 

impinged during winter (December, January, February) 1975-1982 

at the D. C. Cook Plant, southeastern Lake Michigan. 

was defined as months of minimum average water temperature. 

Species composition of the total number of fish 

Winter 

49 
were generally >SO mu (Appendices 25, 27, 29, 31, 33, 35, 37, 39). 

The minimum site retained by the traveling screens was generally 50 mm. 

'In contrast, field-caught spottail shiners included a large component of YOy 

fish which were recruited to our seining gear (Appendices 26, 28, 30, 32, 34, 

36, 38, 40). Peak spawning for spottail shiners occurs in July (Jude et 

al. 19791, when they also begin their post-spawning migration offshore, Large 

late summer impingement losses of spottail shiners during 1978-1980 were 

probably due to increased activity and offshore movement during these months. 

Impingement of adult spottail shiners during October was presumed to be 

related to their offshore migration which takes them past the influence of the 

intakes. A similar event occurred in 1975-1977 for YOY spottail shiners which 

by this time were large enough to be retained on the traveling screens 

(Appendices 25, 27, 291, A few spottails remained inshore all winter. Winter 

impingement rates seemed to be directly related to water temperature, since 

rates increased when water tauperature in the area rose to 3.C or above, but 

there were exceptions. 

spottail shiners was probably afmcted by attraction to the warm-water plume, 

winter storms, and ice cover. 

Beside water temperature, winter impingement of 

Impingement of trout-perch began to increase in April, becomfng high in 

June and July. 

continues throughout I-. 

highly variable, but it appear@ to coincide with upwelling or storms. 

In June, trout-puch move inshore for spawning, which 

Impingemaat of trout-perch during summer was 

Impinged fish wwe generally 80-150 am in length. Over 50,000 trout-perch 

were impinged during July 1978, which was the highest impingement loss of 

trout-perch for a month in supp~per (Appendices 41-56). During most years, 

impingement losses tapered off during late summer and rose again in September 

50 
Or October as offshore trout-perch migrations placed fish in the influence of 

the intakes. A few trout-perch were impinged during winter. 

nopingernant of yellow perch increased slightly in March and April, as 

inshore water temperatures warmed in spring. 

occurred during June through September, except for 1975. 

after the spawning season (late May-early June) for yellow perch, their midto-late su1p1p8t abundance evidently reflected post-spawning migrations into the 

vicinity of the intake area after spawning in other areas of the lake (Jude et 

al. 1979, Dorr 1982). There is some evidence that impingement of yellow perch 

during slt"mrr increased sharply after storms (Lifton and Storr 1977; personal 

observations). 

Septembar and continued to k impinged during fall and winter, showing that at 

least sane fish remained inshore through most of the winter (Appendices 57- 

72). 

Peak impingement of yellow perch 

Because this was 

Young-of-theyear yellow per& were first impingad in 

Impingement of rainbow melt usually peaked during spring, most often 

during April and Uay. 

area as they migrate inshore to spawn (Jude et al. 1979). 

rkinbow smelt prefer cold water (Wells 1968, Jude et al. 19791, they move 

off shore during months of warm-water temperatures . Impingement of rainbow 

smelt during the slll~mer usually occurred when cold, upwelled water allowed 

rainbow smelt to move shoreward. 

rainbow smelt were impinged during smer. 

were impinged in Septembu and October (Appendices 73-88). 

During these months, rainbow smelt move past the intake 

Because adult 

During 1978 through 1981 large numbars of 

Young-of-theyear rainbow smelt 

Fish impingement during 1980 through 1982 was distinguished by extremely 

large numbers 

exceptionally 

of fish impinged during April-June, beginning with the 

high losses which occurred during April 1980. Losses were high 
for most spades during these months, particularly for almives. my yellow 

perch were impinged during June of these years, although not in previous 

years. 

Winter impingemant losses were exceptionally high during January and 

~ecemb.t 1981. The species impingd at this time wue species most likely to 

be found inshore during winter; ..go, spottail shinu, yellow parch, troutperch (Decunber only), and rainbow smelt. 

IMPINGED FISH COMPARED WITH FIELD-CAUGFT FISH 

In general, species that were most abundant in fmpingamnt collections 

(Tables 2-17) ware also most abundant in field catches (Tables 19-28). 

Spottail shiners camprisai a highu percentage of field catchos (231 of all 

fish caught in standard series fishing 1975-1982, Tesar and Jude 1985) than of 

impingemant losses (10% of total). Though spottail shiners wue locally 

abundant, khey apparently ware not attractd to tho intake structure and may 

evan have avoidd the area; they were most abundant inshore of the intakes 

(Tesar and Jude 1985). Sculpins were impfnged in much higher numbers than 

would be predicted frao field catches. 

(Dorr and Miller 1974, Dorr and Jude 1980) observed that sculpins were found 

in much highu densities in the riprap around intake structures than 011 

adjacent sand; their propensity for hiding in dark places and their nocturnal 

Benda and Gulvas (1976) and our divers 

activity pattuns probably increased their susceptibility to entrapment. 

The relationship among fish impingement losses, field abundance, and 

volume of water circuhtd through the plant varied with species. An analysis 

was conducted using multiple correlation to determine if significant 

relationships existed anmg these threa variables: fish impingeamit losses, 

52 
field abundance of fish, and volume of water circulated through the plant. 

me total weight of alewives impinged over 5-day periods, corresponding with 

the same 5-day periods in which our eight field sampling trips per year were 

performed during 1975-1982, was used for the first variable. 

alewives gillnetted at stations in the vicinity of the intakes was the second 

variable, and volume of cooling water circulated during those periods was used 

as the third variable. 

three variables for alewives. 

impingement rates and the latter two variables was also positive, but less 

strongly so, possibly because yellow perch may be less randomly distributed 

throughout the area (G. Godun, unpublished manuscript, Great Lakes Research 

Division, University of Michigan, Ann Arbor, Mi&.). 

abundance was a better predictor of impingement loss than volume of cooling 

water pumped. 

The number of 

There was a Strong positive correlation among these 

The relationship between yellow perch 

For both species, field 

A second analysis was done by pooling data within a year, providing eight 

data points. 

predicted impingement (C. Madanjian, unpublished manuscript, Great Lakes 

Research Division, University of Michigan, Ann Arbor, Mich.). Annual field 

abundance of alewives was negatively correlated with annual impingement loss. 

Part of the reason for this finding has already been discussed, and involves 

the high impingement rates during 1980-1982 during the time when alewife 

populations lakewi.de were declining dramatically. 

and not pooling data) of colnparing impingement loss with field abundance 

indicate that fish impingement at any given time is probably related to the 

In this case, volume of cooling water pumped more precisely 

These two methods (pooling 

momentary abundance 

necessarily reflect 

of fish in the vicinity of the intake but may not 

seasonal or yearly changes in the inshore abundance of 

53 
certain species. 

impingment losses (Tables 2-17) were compared with field catches (Tables 19- 

28). Annual bpingment losses among other abundant species more closely 

followed field abundance but often shoud 1 or 2 years when the two variables 

were not correlated. Annual ippPingernMt losses of trout-perch during onrunit 

operation (1975-1977) (Tables 2-71 and rainbow smlt during two-unit operation 

(1978-1982) (Tables 8-17) wue nagatively correlatd with annual field 

abundance of these two species (Tables 21-28) The differences may be 

partially explained by limitations of field sampling, because 

only samples during one 24-h puiod each month, but this explanation alone is 

inadequate. Young-of-theyear fish were often more abundant in field catches 

than they were in impingemant samples, because they ware most likely to be 

inshore of the intakes and because they uue too small to be impinged. 

The years 1980 through 1982 held some especially sharp contrasts, 

particularly for alewives, which daclind prmcipitously in field abundance 

during this time (Tables 19-28, Fig. 1; Jude and Tesu 1985) but which 

continued to be impinged in extremely large numbus (Tables 12-17). 

other spedes, particularly yellow perch, which respond& positively to the 

alewife docline, Md to a lesser extent, slw sculpin and rainbow smelt, were 

more abundant during these yaars than previously in both fiU and impingemsnt 

samples. Blortur werm relatively abundant in field catches during 1980-1982, 

particularly 1981, perbaps resulting from several intense upwellings during 

June and July, 1981 (Appendb 7). 

high during this time, as it was in 1978-1979, but both fmpingaaent losses 

(Table 16) and field abundance (Table 28) declined in 1982. Field abundance 

This was particularly true of alewives when y-ly 

gear type 

Several 

Impingement of bloaters u8s meptioMlly - 

54 
and population changes among all species is discussed in detail in Tesar et 

al. (1985), Tesar and Jude (1985) , and Jude and Tesar (1985) 

Disproportionately high entrapment rates may Occur when fish are 

attracted to the riprap or the intake structures. 

temperature changes also increase horizontal or vertical movements of fish, 

which can lead to decreased fish avoidance of the intake structure and 

increased impingement losses. 

which are attracted to the riprap and apparently prefer that substrate over 

the flat, featureless sand bottom which characterizes field sampling stations. 

Sculpins, in particular, as confirmed by project divers (Dorr and Jude 19801, 

reside on the riprap almost exclusively. 

yellow perch around the intakes (Dorr and Jude 19801, and yellow perch, 

sculpins, johnny dartef, spottaii shiner, and ninespine stickleback may use 

the riprap as spawning substrate (Dorr 1982). 

Weather or water 

Sculpins and yellow perch are examples of fish 

Divers also observed aggregations of 

Trout-perch and rainbow smelt, however, are mles of fish which are 

not normally attracted to the intakes or riprap. Even when present inshore, 

they may not be impinged in large numbers unless weather or water temperature 

changes OCCUT. 

attracted to the intakes, increases when fish activity increases. 

spring warming of inshore water, fall overturn, upwelling, and storms are all 

Entrapmeut of all fish, even those which normally are 

Spawning, 

conditions which increase fish movement through the area of the intakes. 

Upwelling can force fish to me upward in the water column (Emery 19701, 

which increases their chances of entrapment. 

during storms, but may seek shelter in the lee of an intake structure (Lifton 

and Storr 1977). 

reduce fish awareness and avoidance of the intake structure and current. 

Fish not only are more active 

Turbidity and turbulence associated with storms may also 
6 Two-unit operation increased cooling water flow rate Fran 2.7 x 10 

iiters/min to 6.1 x lo6 liters/min (USAEC 1977) and, during certain times of 

the year, increased fish impingement substantially over impingement during 

one-unit operation. In ma&ing comparisons of imphaanent rates, 1977 was not 

considerd because so few fish were impingd canpard with the precaiing 

2 years. Because 1977 was a year of one-unit opuation, its -1usion should 

# 

contribute to a more conservative estimate of the differences between one-unit 

and two-unit operation. Initial years of two-unit operati=, 1978 and 1979, 

are compared separately fran 1980-1982 because Unit 2 pumping during 1978-1979 

was erratic, especially during the spring, a key high puiod of impingamnt 

loss. 

1980 . 

The full effect of sustain& two-unit Ming was not obs.rved until 

The largest percat increase in impingement losses for spottail shiner, 

trout-perch, and rainbow smelt occurred in 1978-1979 (Table 30). 

increase was probably a direct result of the plant pumping schedule which 

This 

increased pumping rates dramatically when Unit 2 cam on line in 1978. 

Howevet, monthly pumping volumes were erratic and seldom involved more than 

three pumps for any utdd period of time during spring and early SIJLPPML: of 

these 2 years, which resultd in lower impingment rates for fish usually 

abundant during these months. In contrast, volume of water pumpd during 

July-Decembrt, 1978-1979 Was high (Table 18) Md ItmpbgglUlt 10SS.S alWng 

species which were abYndant during these months were substantial (Tables 8- 

11). 

spring and early surmper months of 1980 through 1982 (Table 181, with 

Both units were opuating at nearly full capacity during most of the 

56 
Table 30; 

change in volume of water pumped and number of fish 

impinged annually at the D. C. Cook Plant. Comparisons are 

among years of one unit operation (1975-19761, years when 

two units operated sporadically (1978-19791, and years of 

full two unit operation (1980-1982). The year 1977 was not 

included because volume pumped was exceptionally low and 

not considered characteristic of full one unit operation. 

See text for full explanation. 

A comparison between two periods of the percent 

Comparison 

1975-1976 1978-1979 1975-1976 

to 1978-1979 to 1980-1982 to 1980-1982 

Volume of 

wdter pumped 87 15 114 

Major fish sDecies 

Alewife 97 374 

Spottail shiner 577 -35 

Yellow perch 114 463 

Trout-perch 303 -64 

Rainbow smelt 1,226 112 

832 

342 

1,103 

12 

2,721 

57 
concomitant high impingement losses (Tables 12-17) among species (especially 

alewife and yellow perch) which are normally abundant during these months. 

when the period 1975-1976 (consistent one-unit operation) was compared with 

the period of consistent two-unit operation (1980-1982), a 1141 increase in 

volume of water pwqed was acconpinied by increased impingomat losses among 

major species ranging frm 342% to 2,7211 (Table 30). Trout-puch ware M 

exception; losses declincd during 1980-1982. 

Tesar 1985, Teuu and Jude 1985) show& trout-perch declined substantially in 

Field abundance data (Jude and 

1982 compared to earlier yeart, possibly due to increasdl predation by the 

burgeoning yellow perch population. 

Data from 1980 to 1982 indicate that full two-unit operatian can result 

in srtremely largo numbers of fish impingd in a short period of time. 

In 19808 ovu 1 million fish were *bgdl during a 3-wk pUid in April and 

May. Zion Station, a nuclear power plant in Illinois (Lake Michigan) 

experienced a similar influx of alewives during May 1975 (Kitchel 1975). 

Heavy impingement losses may possibly affect local abndance of iupactd 

species, especially in cmrihinrtion with total impingemant losses 

southern basin of Lake Michigan. 

within the 

Jensen et al. (1982) estimated that water 

withdrawal bough all intakes an Lake Michigan reduced alewife biomass by 

nearly 31, basd on 1975 data. Many fish impingd at the Cook Plant during 

peak periods in 1978 through 1982 were YOY or yearlings which had not spawned 

(Appendices 15-23). 

detrimsntal bocause of their high production potential (R8go 1979). 

Losses among this age-group might be particularly 

Rag0 (19791, in calculating production forgone due to entrainment and 

impingement of larval and adult fish, indicates that most production forgone 

results from losses among post-larvae tl.'rr%gh yearlings. Through 1981, over 
80% of alewife production forgone was attributable to entrainment (P.J. Rago, 

unpublished ms); however, impingement of YOY and yearlings contributed 

significantly- to rainbow smelt losses and dominated yellow perch production 

forgone (Rag0 1979). If alewives continue to decline in abundance and are 

replaced inshore by other species, impingement losses may became increasingly 

important to total production forgone. Jensen et al. (1982) felt that the 

biomass of fish impinged on Lake Michigan had more impact on stocks of 

abundant species than did entrainment of larvae. 

by the high predation pressure on alewife by salmonids (Stewart et al. 1981; 

unpublished data, Great Lakes Research Division). 

rainbow smelt, were impinged during 1983 and 1984, and yellow perch were very 

abundant in gill nets set at Cook Plant stations for radiological monitoring 

(E. Mallon, pusonal cammunication, 0. C. Cook Plant, Bridgman, Mich.). 

His prediction is confounded 

Few alewives, but many 

MITIGATIVE MEASURES FOR IMPINGEMEHT 

There are several structural or functional modifications of the intake 

system which might reduce or eliminate impingement and -even entrainment of 

fish. Engineering and economic constraints of most of these alternatives are 

discussed at length by IMPC (1979). Bimber et al. (1984) discuss the 

effectiveness of several alternatives in reducing entrainment. 

Perhaps the most favored system is fine-mesh, wedge-wire screens. 

Intakes of this type currently installed at the J. H. Campbell Plant 

eliminated impingement and reduced entrainment for some species (Jude et 

al. 1982, Zeitoun et al. 1981). Smaller mesh sizes (mesh size of Campbell 

screens is 9.5 mm> might reduce entrainment further, but not substantially 

(Schneeberger and Jude 1981). Smaller mesh size, however, requires mre 

59 
frequent cleanbg and reduces flow (IMPC 1977). The suitability of this 

technology for a plant with cooling water requirements as large as Cook's is 

still unproven. Because of the low flow velocities cbaracteristic of this 

system, construction would require an intake field substantially larger than 

currently exists at the Cook Plant, resulting in a significantly larger riprap 

area which would provide substantial spawning habitat. 

\ 

This could result in 

an actual increase in entrainumt of larvae of certain spmcies, such as yellow 

perch (Jude et al. 1982) and possibly lake trout, which would be attracted to 

the area. 

A barriu net which surrounds the intake structure .and ptWoritS fish 

entraporit was used with apparent success at Won Station, Lake Michigan 

(Kitchel 1975) and in Lake Erie (J. Gulvas, personal comunication, Consumeirs 

Power corqwurY, Jackson, MI). The S-cm stretch-nnsh net was installed during 

April-Nwuubu and appearad to be effactivo in reducing Fmpingeut8nt of adult 

,alewives. 

Nanticoke Plant in Lake Ontario helped reduce inpingment losses by 64-845 

A fine-mesh knthic a8t placad around the intake at Ontario Hydro's 

(Poster 1981). Tne net was not sizrseloctive but was species-selective, 

deterring emerald shiner, rock bass, spottail shiner, trout-perch, white bass, 

and yellow parch more affoctivoly than alewife and sam othu species. The 

barrier net was not rocOmDIILdd, howaver, because it was vulnuable to wave 

action and ice scour, 8 drawback which should not be a problem if the nets 

were rapovd smasonally. A barriu net is a possibility for the Cook Plant, 

but a more carotul stwiy should be macia of the effectiveness and &tmance 

raquirenants of the nets which have been tried in the Great Lakes. 

Other possibilities for alleviating impinganent losses include 

operational strategies which would require no structural changes in the 

60 
intake. The most effective approach would be to curtail volume of water 

pumped through the plant during months of maximum impingement. Over 801 of 

all fish were winged from April through July, though most YOY were impingrd 

. 

from August through October. During two-unit operation, an average 542 of 

annual impingement losses have occurred in 1 month, June, while the secondlargest losses usually occurred in May. 

through the plant during May-July should result in impingement of less 

biomass, while curtailment during September and October should result in fewer 

YOY impinged. A lower volume of water pumped could be achieved by scheduling 

refueling and maintenance during these months. 

reducing power output by the plant would result in a AT exceeding the ma~~imupp 

AT of 22 OF + 1 *F for Unit 1 or 17 OF + 1 OF for Unit 2 specified by Nuclear 

Regulatory Commission enviromental technical specifications. 

plume effects (IMPC 19771, as well as those of others (Kelso and Minns 19751, 

indicate no biological reason why a compromise'could not be reached to reduce 

fish impingement losses at the plant. 

zooplankton, benthos) would also have to be taken into consideration. 

Curtailment of volume of water pumped 

Reducing volume pumped without 

Our analyses of 

Impact on other biota (phytoplankton, 

Reducing flow at night might also reduce impingement. Though we made no x 

diel studies, there is some evidence From other plants that more fish are 

' impinged at night (Benda and Houtcooper 19761, and more fish larvae are 

entrained at night at the Cook Plant (Bimbet et al. 1984). 

The D. C. Cook Nuclear Power Plant is a two-unit, 2,200 mW utility 

located on the shores of southeastern Lake Michigan. The plant began Unit 1 
operation in 1975, and Unit 2 came on line in 1978. Both units together 

require 6.3 x lo6 literdmin for cooling water which is drawn fram three 

intakes located in about 7 m of water. 

first with 6.60- trash bars, then with 9.5- bar mesh traveling screens. 

Juvenile and adult fish too large to pass through the screens are retained, 

removed with a jet spray, and sluiced into larger baskets. Plant personnel 

bagged and froze all fish, and University of Michigan personnel processed 

samples of all fish in 1975 and samples from every fourth day in 1976-1982. 

These data were used to generate inpingemant losses for all species on a 

monthly and annual basis. 

losses with our concurrently collected field samples and with the total volume 

Water entering the plant is screened 

In addition, we compud trends in impingement 

Of -tu pumpd through the plant. 

Annual Imphgemmt losses at the D. C. Cook Plant over 1975-1982 ranged 

froid 53,190 (1,833.34 kg) fish in 1977 to 2,307,654 (71,208.81 kg) in 1980.' 

Each yeat was characterized by a month of peak impingemalt during June or July 

and often a secondary peak in spring (April-May). 

comprised over 682 of the total loss, spottail shiner 102, yellow perch 92, 

trout-perch 52, rainbow smelt 42, slimy sculpin 22, while 55 less conwn 

species made up the ranaU.ng loss (e%). 

Pooled over years, alewife 

During consistemt two-unit operation in 1980-1982, an average of over 

1,000 salmonids was impinge per year. 

percentage of losses varied each year from juvenile chinook salmon in 1980 to 

lake trout in 1981, and adult coho salmon in 1982. 

The fish comprising the highest 

During May 1980, we recorded a large number of previously dead alewives 

in impingement collections. We felt these fish entered the forebay during the 

62 
high impingement events in late April and May and died in the forebay from 

stress and overcrowding. - 

The variability among years in impingement losses was a function of 

abundance of various age-groups of fish in the lake and their behavior during 

major physical events (thermal bar, storms, strong current). A second 

important factor was pumping rate, and whether maximum pumping rates occurred 

during certain key months when fish were particularly susceptible to 

impingement. In addition, during the early 1980s, alewives suffered a 

dramatic decline in Lake Michigan, with several species (yellow perch, rainbow 

smelt, bloater) increasing in response to the decline. However, alewives 

still comprised a high percentage of the losses in 1980-1982, which is 

partially related to high prrmping rates in the spring and persistence of the 

thermal bar. 

alewives now comprise a substantially lower percentage of the catch. 

More recent data collected by power plant personnel suggest that 

As yellow perch, rainbow rmelt, and bloaters increased in abundance in Lake 

Michigan, they also were impinged in higher numbers. 

Biology and behavior were important determinants of the susceptibility of >c 

individual species to impingement. 

spawning and feeding, and in response to temperature, brought different 

Seasonal and diel movements because of 

species at different times into the influence of the intakes. 

which decreased the avoidance capabilities of fish, such as darkness, storms, 

Any factors 

or high currents, caused increased impingement of species in the vicinity of 

the intakes. Alewives were particularly susceptible as they moved shoreward 

in spring and concentrated within the thermal bar seeking warm water. 

Persistence of the bar led to impingement of large numbars of alewives and 

other species each spring. The preference of spottail shiners for nearshore 

63 
areas reduced their Fmpingement susceptibility, while other species, such as 

sculpins and johnny darters, preferred the riprap around the intakes and were 

impinged in large numbers as a consequence. 

movement nearshore of cold water species, such as lake trout, bloaters, and 

rainbow smelt. 

related to upwelling frrquurcy. 

Upwellings resulted in the 

Their impingerpmt losses during sumpdt appaared to be directly 

Unit 2 became fully opuational in 1978, but consistent pumping rates 

were not maintained until 1980. 

unit operation) was compared with 1980-1982 (consistent two-unit operation), a 

114% increase in volume of water pumped was accompanied by increased 

impingement losses among major species ranging from 342% to 2,7211. 

unit opuation resultd in tho impingement of over 1 million fish during a 3= 

wk period in April-Wy, 1980. 

When tho period 1975-1976 (consistent oneFull two- 

\ In general, species that were most abundant in field catches wae also 

most abundant in inpingamant collections, with alowifo dauinant in both. 

Spottail shiners comprised a higher proportion of field collections than 

impingement losses because they were cancentrated inshore of the intakes and 

may have wen avoided them. Other species, such as sculpins, comprised a low 

percentage of fidd catches, but wue attractd to tho riprap and impinged in 

high numbers. 

Production forgone estimates (Rag0 1979) showed that over 801 of the 

production loss for alewife was attributable to entrainmat. 

YOff and yearlings contributed significantly to rainbow zmcrlt losses and 

dominated yellow perch production forgone losses. 

Impingeanent of 

Reduction in impingement losses could be obtained by installation of 

wedge-wire screens, but cost constraints, biofouling, and operational 

6L 
feasibility in shallow water may preclude their use. 

troublesome, may be another mitigative device useful in curtailing impingement 

losses, particularly if barrier net use targeted known periods of high 

impingement losses (e.g., 808 by number of all fish was usually impinged in 

April-July). 

most of which would require Nuclear Regulatory conmission approval. 

would include curtailment of volume of water pumped through the plant during 

high impingement periods. Scheduling rnaintenance and refueling during these 

months would accomplish that. Decreased volume could also be attained by 

increasing the AT of the cooling water. 

documented higher impingement rates, would also result in lowered impingement 

10s sa. 

Barrier nets, although 

Another avenue of approach involves changes in plant operation, 

This 

Reduced flow at night, a period of 

Collection and processing of impinged fish was a labor intensive effort 

and we thank the many people who carefully pried loose rotted alewives, 

debris, dune grass, and sticks, and who meticulously recorded reams of data 

for this report. We appreciate the cooperation we received from Jon Barnes in 

the early days and more recently Eric Mallon and Tom Kreisel of the Cook Plant 

staff. To all those Cook Plant personnel who exercised care in bagging 

impinged fish we extend our thanks. We particularly thank Frank Tesar, John 

Dorr 111, Tim Miller, Paul ago, Greg Godun, Don Efnhouse, Dave Bimber, Rich 

Palacios, and Mike Enk for their substantial contributions to the collection 

and processing of samples and for several computer programs which efficiently 

crunched our massive datasets. Russ Moll is thanked for his thoughtful and 

65 
vw helpful review. 

their many talents in text processing and figure preparation. We thank Bey 

McClellan and Steve Schneidetr for final report refinements and publication. 

Pam Mansfield, Xeang Tin, and Mary Sweeney contributed 

66 
LITERATURE CITED 

Benda, R. S., and J. A. Gulvas. 1976. Post-operational effects of the 

Palisades nuclear power plant. 

R. W. Mc Farlane, eds. Thermal Ecology Symposium, Institute of Ecology, 

Univ. Georgia, Augusta, Ga. 

Pages 243-250 & G. W. Esch and 

Benda, R. S., and W. C. Ifoutcooper. 1976. Impingement studies at 16 electrogenerating plants in Michigan. Pages 291-315 & L. D. Jmsen, ed. Third 

National Workshop on Entrainment and Impingement. 

Inc., Melville, N.Y. 

Ecological Analysts, 

Bimber, 0. L., M. Perrone, Jr., L. S. Noguchi, and D. J. Jude. 1984. Field 

distribution and entrainment of fish larvae and eggs at the Donald 

C. Cook Nuclest Power Plant, southeastern Lake Michigan. 

105. Great Lakes Res. Div., Univ. Mich., Ann Arbor, Mich. 320 pp. 

Spec. Rep. NO. 

Brandt, S. B. 1980. Spatial segregation of adult and young-of-the-year 

alewives across a thumcline in Lake Michigan. Trans. Amer. Fish. Soc. 

109:469-478. 

Brandt, S. B., J. J. Magnuson, and L. B. Crowder. 1980. Thermal habitat 

partitioning by fishes in Lake Michigan. Can. J. Fish. Aquat. Sci. 

37 : 1557-1564. . 

Dorr 111, J. A. 1982. Substrate and other environmental factors in 

reproduction of the yellow perch (Perca flavescens) 

Univ. Mich., Ann Arbor, Mich. 

Ph.D. thesis, 

276 pp. 

Dorr 111, J. A., and D. J. Jude. 1980. SCUBA assessment of abundance, 

spawning, and behavior of fishes in southeastern Lake Michigan near the 

Donald C. Cook Nuclear Plant, 1975-1978. Mfch. Acad. l2:345-364. 

Dorr 111, J.A., and T. 3. Miller. 1974. Undemater operations in 

southeastern Lake Michigan near the Donald C. Cook Nuclear Power Plant 

during 1973. Pages 465-475 & E. Seibel and J. C. Ayers, eds. 

The biological, chemical and physical character of Lake Michigan in the 

vicinity of the Donald C. Cook Nuclear Plant. Spec. Rep. No. 51, Great 

Lakes Res. Dfv., Univ. Mich., Ann Ubor, Mich. 

Eisele, P. J., and J. F. Malaric. 1977. A conceptual model of causal factors 

regarbfng gizzard shad runs at steam electric power plants. 

298 & L. D. Jensen, ed. 

Impingemant. Ecological Analysts, Inc., Melville, N.Y. 

Pages 291- 

Fourth National Workshop on Entrainment and 

Emery, A. R. 1970. Fish and crayfish mortalities due to an internal seiche 

in Georgian Bay, Lake Huron. J. Fish. Res. Board Can. 27:1165-1168. 

67 
Fos tar, J. R. 1981. The efficiency of a benthic net and chain curtain in 

diverting fish. Pages 261-271 in P. B Don and J. T. Johnson, as. 

Advanced intake technology for power plant cooling systems. U.S. Fish 

and Wildlife Service, Washington, D.C. 

Freeman 111, R. F., and R.K. Sharma. 1977. Survey of fish impingement at 

power plants in the United States: Volume II. 

National Lab. Publ. ANL/ES-56. Argonne, Ill. 328 pp. 

theoretical and obsuvational modal study. Spec. Rep. No. 43, Great 

Lakes Res. Div., Univ. nich., Ann Arbor, Mich. 

Inland waters. Argonne 

Huang, C. K. 1969. The thermal current structure in Lake Michigan - a 

Indiana and Michigan Powu Campany (IMPC) . 1977 Report on the inpact of 

cooling water use at the Donald C. Cook Nuclear Plant, 

Mi&. Wat. Res. Corn. Ind. Mi&. Power Co., Fort Wayne, Id. 194 pp. 

Submitted to 

I rdiaM and Michigan Power Company (IMPC). 1979. Supplemantal report 

demonstrating compliance with section 316(b) of the clean water act. 

Submitted to Mich. Wat. Res-. Corn, Ind. Mich. Power Co., Fort Wayne, 

Ind. 129 pp. 

Jensen, A. L., S. A. Spigarelli, and M. M. names. 1982. Use of 

conventional fishery models to assess entrainment and impingement of 

threm Lake Michigan fish species. Trans. Amer. Fish. Soc. 111:21-34. 

Jude, D. J., and F. J. Tesar. 1985. Recent changes in the forage ffsh of 

Jude, D. J., F. J. Tesar, J. C. Tamlinson, T. J. Miller, N. J. Thurber, 

G. G. Godun, and J. A. Dorr 111. 1979. Inshore Lake Michigan fish 

populations near the D.C. Cook Nuclear Power Plant during preoperational 

years - 1973, 1974. Spec. Rep. No. 71, Great Lakes Res. Div., 

Univ. Mich., Ann Arbor, Mich. 529 pp. 

Lake Michigan. Can. J. Fish. Aquat. Sci. 42:1154-1157. - 

Jude, D. J., C. P. Madanjian, P. J. Schneeberger, H. T. Tin, P. J. Mansfield, 

T. L. Rut-, G. E. Noguchi, and G. R. Eieufelder. 1982. Adult, 

juvenile and larval fish populations in the vicinity of the 

J. H. Canpbell Powu Plant, 1981, with special reference to the 

effectiveness of wdge-wire screens in decreasing entrainmant and 

impingemuit. Spac. Rep. No. 96. Great Lakes Res. Div., Univ. Mich., Ann 

Arbor, Mi&. 519 pp. 

Kelso, J. R. M., and C. A. Minns. 1975. Sumner distribution of the nearshore 

fish camunity neaf a thermal generating station as determined by 

acoustic census. J. Fish. Res. Board Can. 32:1409-1418. 

Kitchel, M. 1975. Screen monitoring study. Pages 237-260 Operational environmental monitoring in Lake Michigan near Won Station, July 1974 

through June 1975. Vol. IV. Annual Report to Comonwealth Edison Co., 

Nalco Environmental Science, Northbrook, Ill. 
Lifton, W. S., and J. F. Storr. 1977. The effect of environmental variables 

on fish impingement. Pages 299-311 in L. D. Jensen, Ed., Proceedings of 

the Fourth National Workshop on Entrainment and Impingement. Ecological 

Analysts, Inc., Melville, N.Y. 

Loar, 3. M., J. S. Griffith, and K. D. Kumar. 1977. An analysis of factors 

influencing the impingement of threadfin shad at power plants in the 

southeastern United States. Pages 245-255 & L. D. Jensen, ed. Fourth 

mtional workshop on Entrainment and Impingement. Ecological Analysts, 

Inc., Melville, N.Y. 

Mortimer, C. H. 1973. Lake hydrodynamics. Mitt. Theoret. Verein. Limnol. 

20:124-197. 

Rago, P. J. 1979. On the calculation of production forgone due to 

entrainment and impingement of fishes at the Donald C. Cook Nxlear 

Plant. 

of the clean water act. Volume I. Ind. Mich. Power Co., Fort Wayne, 

Ind. 129 pp. 

Supplemental report demonstrating compliance with section 316(b) 

Schneeberger, P. J., and D. J. Jude. 1981. Use of fish larva morphometry to 

predict exclusion capabilities of small-mesh screens at cooling-water 

intakes. Trans. mer. Fish. SOC. 110:246-252. 

Sharma, R. K., and R. F. Freeman. 1977. Survey of fish impingement at power 

plants in the United States: Volume I. 

National Laboratory publication ANL/ES-56. Argonne, Ill. 218 pp. 

The great lakes. Argonne 

Stewart, D. J., J. F. Kitchell, and L. B. Crowder. 1981. Forage fish and 

their salmonid predators in Lake Michigan. Trans. mer. Fish. SOC. 

110:751-763. 

Tesar, F. J., and D. J. Jude. 1985. Adult and juvenile fish populations of 

inshore southeastern Lake Michigan near the D. C. Cook Nuclear Power 

Plant, 1973-1982. Spec. Rep. No. 106, Great Lakes Res. Div. Univ. Mich., 

Ann Arbor, Mich. 94 pp. 

Tesar, F. J., D. Einhouse, H. T. Tin, 0. L. Bimber, and D. 3. Jude. 1985. 

Adult and juvenile fish populations near the D. C. Cook Nuclear Power 

Plant, southeastern Lake Michigan, during preoperational (1973-74) and 

operational (1975-79) years. Spec. Rep. No. 109. Great Lakes Res. Div., 

Univ. Mich., Ann Arbor, Mich. 341 pp. 

Thurber, N. J., and D. J. Jude. 1984. Impingement losses at the D.C. Cook 

Nuclear Plant during 1975-1979 with a discussion of factors responsible 

and relationships to field catches. Spec. Rep. No. 104, Great Lakes 

Res. Div., Univ. Mich., Ann Arbor, Mich. 99 pp. 

69 
u.S. Atomic Energy Comnission (USAEC). 1373. Final environmental statanent 

related to operation of Donald C. Cook Nuclear Plant units 1 and 2. 

Docket nor. 50-315 and 50-316. Directorate of Licensing, US. Atan. 

mer. Ccarm., Washington, D.C. 327 pp. 

Wells, L. 1968. Seasonal depth distribution of fish in southeastern Lake 

Michigan. Fish. Bull. 67:l-15. 

Zeitoun, I. H., J. A. Gulvas, and D. E. Roatabaugh. 1981. Effectiveness of 

fine mesh cylindrical wedgc-wire screens in reducing entrainment of Lake 

Michigan ichthyoplankta. CM. J. Fish. Aquat. SCi. 38:l20-125. 

70 
30 

286 I 1975 

2u 

22 

- 20 

18 

= 16 

u 

Y 

W 

3 

& lU 

E 12 

+8 

e 

W = 10 

6 

u 

2 

0 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

Appendix 1. 

the St. Joseph municipal water plant during 1975. 

was 6 m. 

Lake Michigan water temperatures recorded daily at 

Intake depth 

A- 1 
30 

28 

26 

2u 

22 

20 

10 

16 

ltl 

12 

10 

0 

6 

u 

2 

I976 

u I I I I u I I I I I I 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

Appendix 2, Lake Michigan water temperatures recorded daily at 

the St. Joseph municipal water plant during 1976, Intake depth 

was 6 m. 

A- 2 
0 

u 

Y 

W 

3 

+ 

a 

a 

a 

W 

(L 

I: 

w 

c 

30 

28 

26 

2u 

22 

20 

18 

16 

14 

12 

10 

8 

6 

tl 

2 

1977 

Ol I I I I 1 I 1 I I I I I 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

Appendix 3. 

the St. Joseph municipal water plant during 1977. 

was 6 m. 

Lake Michigan water temperaturks recorded daily at 

Intake depth 

A- 3 
c. 

u 

Y 

W 

3 

#- 

a 

a 

a 

W 

Q. 

z 

W 

I30 

28 

26 

2u 

22 

20 

18 

16 

ltl 

12 

10 

8 

6 

u 

2 

I978 

ii 

JAN'FEB 'MAR 'APR'MAY * JUN JUL 'AUG-SEP-OCT~NOV'DEC 

MONTH 

Appendix 4. Lake Michigan water temperatures recorded daily at 

the St. Joseph municipal water plant during 1978. Intake depth 

vas 6 m. 

A- 4 
n 

u 

Y 

W 

=> 

t 

a 

a 

a 

w 

Q 

x 

W 

t22 

20 

18 

16 

11 

12 

10 

8 

6 

tl 

2 

0 I 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

1 I 1 I I I I I I I I I 

MONTH 

Appendix 5. Lake Michigan water temperatures recorded daily at 

the St. Joseph municipal water plant during 1979. 

was 6 m. 

Intake depth 

A- 5 
n 

u 

Y 

W 

=> 

c 

a 

a 

a 

W 

e 

z 

W 

t 

30 

28 

26 

2u 

22 

20 

18 

16 

ltl 

12 

10 

8 

6 

1980 

- 

I 

P 

Ol 1 1 I 1 a I I I I I I 1 

JAN FEE MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

Appendix 6. 

was 6 m. 

Lake Michigan water temperatures recorded daily at e the St. Joseph municipal water plant during 1980. Intake depth 

A- 6 
30 

28 

26 

24 

n 

u 

V 

W 

ac 

3 

t 

a 

a 

w 

e 

r 

W 

I- 

- 

VI I 8 I I I I I I I I I I 

JAN FEE MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

Appendix 7. 

the St. Joseph municipal water plant during 1981. 

was 6 m. 

Lake Michigan water temperatures recorded daily at 

Intake depth 

A-7 
n 

0 

Y 

W 

3 

c 

oc 

W 

e 

r 

W 

Ja 

a 

30 

20 

26 

2u 

22 

20 

18 

16 

ltl 

12 

10 

8 

6 

li 

1982 

tc 

I I I I I t I I I I 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH 

. 

Appendix 8. Lake Michigan water temperatures recorded daily at 

the St. Joseph municipal water plant during 1982. Intake depth 

was 6 m. 

A- a 
JAN ............................. 

4000" 

FEB ............................. 

I- 

......................... NOV 

MAR 

L 

.... 

4000 

28ow 

12000 

MRY 

4000 

4m 

t- 

........................... SEP L 

I ......... DEC 1 

rn ..... 4mn 1-- . ?OO 3513 c 

3U IUU 13u L-- --- 

TOTAL LENGTH (!In) 

Appendix 9. Length-frequency histograms of alewives impinged 

during 1975 at the Cook Plant, southeastern Lake Michigan. 

A- 9 
1200 

JUN 

zoo 

1200 

3600 

3. 2400 

H 

LL 

0 

IA 1200 

a 

w 

m 

x 

3 

z 

12000 

8400 

7200 

6000 

OCT 

NOV 

210 O~....'...'"...~"'~'.... 

10 60 110 160 

TOTAL LENGTH (MM) 

Appendix 10. 

during 1975 fieid sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-iO 
5 

n 

LL 

LL 

0 

W 

I= 

1 

Z 

a 

m 

1200 

1200 

6ww 

4800 

3600 

2400 

1200 

9600 

1200 

L 

200 

TOTAL LENGTH (MRI 

250 

Appendix 11. 

during 1976 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of alewives impinged 

A-11 
wl 1976 

WR 

4000 

JUL 

m 

H 

L 

LL. 

0 

K 

W 

S 

m 

1 

SEP 

OCT 

a000 NOV or' 60 110 160 210 . ' ' ' . ' ' . ' . . ' . . . 

10 

TOTRL LENGTH (MI?) 

Appendix 12. 

during 1976 field sampling at the Cook Plant, southeastern Lake 

Length-frequency histograms of alewives caught 

Michigan. 

A-12 
TOTAL LENGTH (IWl 

Appendix 13. 

during 1977 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of alewives impinged 

A-13 
lmk 1977 APR 

s 

w 

LL 

LL 

0 

W 

S 

=> 

z 

a 

m 

2400 

lzwl 

1200 

160 

TOTAL LENGTH (RM) 

0 

10 60 110 

96M 

8400 Ii 

4m 

3800 

2400 

1200 NOV 

210 

Appendix 14. 

during 1977 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-14 
4000 

4000 

JUL 

--. . - 

- FEE -.. ........................... - 

4000 

4ooo 

4000 

4ooo 

So00 

50 100 150 200 250 

TOTAL LENGTH (MI11 

Appendix 15. 

during 1978 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of alewives impinged 

A-15 
APR 

JUL 1200 

mw RUG 

Ln 

H 

LL 

LL 

0 

1200 NOV 

60 110 160 210 0 

TOTAL LENGTH ~tlfl) 

10 

Appendix 16. 

during 1978 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-16 
TOTAL LENGTH (MMI 

Appendix 17. 

during 1979 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of alewives impinged 

A- 17 
NOV 

rooQ 

0 

10 60 110 160 210 

TOTRL LENGTH (flfll 

Appendix 18. Length-frequency histograms of alewives caught 

during 1979 field sampling at the Cook Plant, southeastern Lake 

Mi c h i gan 
1 

JRN 

FEB 

- SEP 

OCT 

NOV 

DEC 

12000 

12000 

12000 

80 130 180 230 TOTAL LENGTH (Mnl 

30 

Appendix 19. 

during 1980 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of alewives impinged 

A-19 
160 

960 

800 

640 

480 

320 

160 

800 

640 

480 

320 

160 

960 

8w) 

640 

480 

320 

160 

1280 

1120 

960 

a00 

640 

480 

320 

160 

320 

160 

TOTRL LENGTH (MI71 

Appendix 20. 

during 1980 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-20 
12000 

1- 

12000 

12000 

IOsOOO 

36(#w 

84w)ll 

72ooo 

60000 

48000 

36000 

2m 

12000 

108000 

84OoO 

060000 

36m 

3 24000 

5 96000 

L 7Moo 

f5- 

= 12OOO 

84ooo 

72000 

6M100 

48000 

36000 

24000 

12000 

12000 

12000 

12OM 

12000 

12000 

20 70 120 170 220 

TOTRL LENGTH (flfll 

Appendix 21. Length-frequency histograms of alewives impinged 

during 1981 at the Cook Plant, southeastern Lake Michigan. 

A-21 
8110 ___ t 

SEP 

- 

Appendix 22. 

during 1981 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-22 
Bowlmb 1382 

- FEB L ...................... i 

JAN 

mt ......................... 

1. ...................... - 

- SEP i. 

8aM 

101,019 

.... 

RUG 

......................... 

OCT 

NOV 

DEC 

30 80 130 180 230 

TOTAL LENGTH (BRI 

Appendix 23. Length-frequency histograms of alewives impinged 

during 1982 at the Cook Plant, southeastern Lake Michigan. 

A-23 
210 c 

OCT 

m- NOV 

244 - 

0 110 160 210 

TOTAL LENGTH (tltll 

10 60 

. 

Appendix 24. 

during 1982 field sapling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of alewives caught 

A-24 
-- 

TOTAL LENGTH (flfll 

Appendix 25. 

impinged during 1975 at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of spottail shiners 

A-25 
NUV I 

60 110 160 

TOTFlL LENGTH (MR) 

Appendix 26. 

caught during 1975 field sampling at the Cook Plant, southeastern 

Length-frequency histograms of spottail shiners 

Lake Michigan. 

A-26 
2400 

2000 

16w) 

ma 

800 

40 

m 

400 

40 

JUN 

400 -. 

JUL 

400 

400 

800 

400 

800 

40 

eo0 

400 

30 80 130 

TOTAL LENGTH tllfl) 

Appendix 27. Length-frequency histograms of spottail shiners 

impinged during 1976 at the Cook Plant, southeastern Lake 

Michigan. 

A-27 
160 

no 

160 

800 

640 

480 

320 

160 

1440 

1280 

1120 

960 

800 

640 

480 

320 

160 

160 

NOV 

10 60 110 160 

b 

0; 

TOTRL LENGTH (Rfl) 

Appendix 28. Length-frequency histograms of spottail shiners 

caught during 1976 field sampling at the Cook Plant, southeastern 

Lake Michigan. 

A-28 
c 

720 

540 

560 

480 

400 

320 

240 

160 

80 

400 

80 

80 

80 

80 

80 

320 

240 

160 

80 

80 c NOV 

80 DEC 

30 80 130 TOTAL LENGTH (11) 

Appendix 29. 

impinged during 1977 at the Cook Plant, southeastern Lake 

Michiuan. 

Length-frequency histograms of spottail shiners 

A-29 
1977 

FIPR 

400 

400 

"t I 

t- I 

L 

!- NOV 

10 60 110 160 

4- 

0: 

TOTRL LENGTH (tlfl) 

Appendix 30. 

caught during 1977 field sampling at the Cook Plant, southeastern 

Lake Michigan. 

Length-frequency histograms of spottail shiners 

A-30 
8W' 

rooo8000 

MFiR 4000 

8000 

- JFlN 

- FEB 

- 

c 

L 

4000 

8000 

- 

- APR 

L 

4000 

8000 

- MAY 

- 

c 

4000 

48000 

44000 

5 40000 

36000 

LL 32000 

28000 0 

a # 24000 

f 20000 

= 16Ooo 

12000 

8000 

4000 

8000 

4000 

8000 

L - - RUG L 

4000 

8000 

SEP 

4000 - - OCT 

4000 

8000 NOV 

4000 DEC 

30 80 130 

TOTAL LENGTH (l'lfl) 

Appendix 31. 

impinged during 1978 at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of spottail shiners 

A-31 
1978 

800- 

APR 

- 

7 

JUN 

c 

800 

1600 

800 

800 F r NOV 

110 160 

TOTAL LENGTH (tltll 

60 

0' 

10 

Appendix 32. 

caught during 1978 field sampling at the Cook Plant, southeastern 

Length-frequency histograms of spottail shiners 

Lake Michigan. 

A-32 
1600 

800 

800 

800 I FEB 

flRR 

3200 

24M 

1600 

800 

800 

8w 

3200 

c 

2400 

16M 

800 

L 

4800 

4aao 

3200 

2400 

eoa 

1600 

3200 

1600 

800 

800 

NOV 

DEC 

800 

30 80 130 TOTAL LENGTH (flfl) 

Appendix 33. 

impinged during 1979 at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of spottail shiners 

A-33 
Boot 1979 

800 iNOV or 

10 60 110 160 

400 p 

TOTAL LENGTH UTI1 

Appendix 34. Length-frequency histograms of spottail shiners 

caught during 1979 field sampling at the Cook Plant, southeastern 

Lake Michigan. 

A-34 
IMUL 1980 

16M 

JRN 

L FEB - 

L 

L 

4 

3200 

MQY 

L 

JUL I 1- 

cn 

n 

L 

LL 

0 

RUG 1600 

17600 

16000 

14400 

tzs00 

11200 

36w1 

8000 

6400 

4800 

3200 

1600 

3200 

1600 

NOV 1600 

1600 

20 70 120 170 

TOTAL LENGTH ~fllll 

Appendix 35. 

impinged during 1980 at the Cook Plant, southeastern Lake 

Michigar.. 

Length-frequency histograms of spottail shiners 

A-35 
x 

v) 

H 

LL 

LL 

0 

U 

w 

G 

5 

z 

1980 APR 

- 

2m 

2400 

2m 

16iw 

1200 

800 

400 

400 

2000 

SEP 

OCT 

NOV -. 

10 60 110 

TOTRL LENGTH (MMI 

Appendix 36. 

caught during 198G field sampling at the Cook Plant, southeastern 

Lake Michigan. 

Length-frequency histograms of spottail shiners 

A-36 
I 

v) 

H 

LL 

LL 

0 

w 

a 

m 

5 

z 

1981 

2400 

1200 

2400' JAN 

FEB 

RAR 

APR 

tzoo 

2400 

tloo 

2400 

1241 

1241 

2400 

1200 

2400 

/. OCT 

90 

NOV 

DEC 

140 

TOTAL LENGTH tl'll'l) 

190 

Appendix 37. 

impinged during 1981 at the Cook Plant, southeastern Lake 

Michigan . Length-frequency histograms of spottail shiners 

A-37 
800 

400 

8w 

400 

800 

400 

800 

¶- 

L 

400 NOV 

0 60 110 160 

Length-frequency histograms of spottail shiners 

10 

TOTAL LENGTH ttlfll 

Appendix 38. 

caught during 1981 field sampling at the Cook Plant, southeastern 

Lake Michigan. 

A-30 
c 

nm= 

rrm FEB 

- RUG 

7. JUL 

12m 

t2DamIZM 

- \ SEP 

. OCT 

NOV 

DEC 

- 

- 

- 1 

- 

- 

- 

- 

Appendix 39. Lengthimpinged during 1982 

Michigan. 

frequency h 

at the Cook 

i stograms of spottai 

Plant, southeastern 

1 shiners , Lake 

A-35 
TOTAL LENGTH ttlfll 

Appendix 40. 

caught during 1982 field sampling at the Cook Plant, southeastt 

Lake Michicran. 

Length-frequency histograms of spottail shiners 

I 

I 

zrn 
JAN 

ftQ 

200 

200- 

I LU 

- 

- tlRR 

- APR 4 

flAY 

200 JUN 

200 JUL 

200 

. -- 

200 I1400 't 

290 

10 

c 

6R 110 

TOTAL LENGTH (llll) 

160 

Appendix 41. 

during 1975 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of trout-perch impinged 

A-41 
20 

20 

20 

20 

10 

0 

so 100 1 so 

TOTAL LENGTH (mi 

Appendix 42. Length-frequency histograms of trout-perch caught 

during 1975 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-42 
- 

160 - 1976 JAN c 

160 

FEB 160 

- NOV 

- 

160 

I 

OEC 160 

10 60 110 

TOTQL LENGTH IMR) 

160 

Appendix 43. 

during 1976 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of trout-perch impinged 

A-43 
"Ot 1976 1 

200 

160 ':I 40 

F 

"i 

c 

L 

c 

40 

80 

0 NOV 

so 100 150 

TOTAL LENGTH (Ill71 

Appendix 44. Length-frequency histograms of trout-perch caught 

during 1976 field sampling at the Cook Plant, southeastern Lake 

Mi c hi gan . 

A-44 
120 z 1977 JAN 

- -- 

120 

120 

240 

FE0 

z 1977 JAN 

120 

240- 

120 

240 

APR 

- tlAR ' 

120 

240 

120 ?------- 120 

I- hi tr 

240 

I20 

IS60 

1440 - 

- 

- 

- 

960- 

840 

720 

600 

480 

360 - 

240 - 

120 t- 

- 

- 

- 

. 

nuu 

SEP 

240 

120 

2 40 

120 

1 

TOTQL LENGTH (l7fl) 

Appendix 45. 

during 1977 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of trout-perch impinged 

A-45 
40 

80 

40 

80 

- APR - 

- 

40 

40 

80 

40 - 

80 - 

- 1 . 

i 

tmv I t 1.u v 

100 150 

TOTAL LENGTH tnn) so 

01 

Appendix 46. Length-frequency histograms of trout-perch caught 

during 1977 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-46 
JAN 

JOOE FEB 

Boo 

400 

BM 

RAY 

- 

400- JUN 

56Do 

L 

NOV 400 

8M L 

DEC 400 

10 60 110 160 

TOTAL LENGTH VIfll 

Appendix 47. Length-frequency histograms of trout-perch impinged 

during 1978 at the Cook Plant, southeastern Lake Michigan. 

A-47 
40- 

40 

JUN 

1978 

- APR 

J= 

c .I 

NOV 

-- 

TOTFlt LENGTH (tlfll 

Appendix 48. Length-frequency histograms of trout-perch caught 

during 1978 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-48 
NOV 

2110 ___ DEC 

10 60 110 163 TOTRL LENGTH (RM) 

Appendix 49. 

during 1979 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of trout-perch impinged 

A-49 
8 

NOV 

20 Itoo 150 a 

TOTAL LENGTH (flnl 

50 

Appendix 50. Length-frequency histograms of trout-perch caught 

during 1979 field sampling at the Cook Plant, southeastern Lake 

Michigan. . 

A-53 
I 

v) 

H 

LL 

LL 

0 

w 

z 

3 

z 

a 

m 

'ODJRN 

- 

- 

2000 

c I 

IF 

400 

2000 

1600 

1200 

800 

L 

TOTFlL LENGTH (IlM) 

Appendix 51. 

during 1980 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of trout-perch impinged 

A-51 
40 

I980 bDD 

80 

44 

80 

40 

120 

80 

40 

240 

160 

120 

80 

4u 

40 

NOV 

20 70 120 170 

TOTAL LENGTH (Rfll 

Appendix 52. Length-frequency histograms of trout-perch caught 

during 1980 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-52 
400 1 - 1981 JAN 

800- 

FEB 4oa 

800 c 

4aJt 

em 

440 

400 

em L ~ ~ 

- NOV 400- 

800 

30 80 13u 

TOTAL LENGTH (nM1 

180 

Appendix 53. Length-frequency histograms of trout-perch impinged 

during 1981 at the Cook Plant, southeastern Lake Michigan. 

A-53 
60 

48 

36 

24 

n 

24 

12 

n 

0 

20 70 120 170 

TOTAL LENGTH (llfl) 

Appendix 54. Length-frequency histograms of trout-perch caught 

during 1981 field sampling.at the Cook Plant, southeastern Lake 

Michigan . 

A-54 
L NOV 

- DEC 

- 

20- 

60 110 160 TOTAL LENGTH (MIV 

Appentiix 55. 

during 1982 at the Cook Plant, southeastern Lake MichiaanLength-frequency histograms of trout-perch impinged 

A-55 
c 

I6 

n 

8 

o4 

4 

OCT 

NOV 

20 70 120 170 

4 

0 

- 

TOTRL LENGTH (tlnl 

Appendix 56. Length-frequency histograms of trout-perch caught 

during 1982 field sampling at the Cook Plant, southeastern Lake 

Mi ch igan . 

A-56 
I 

VI 

H 

LL 

LL 

0 

W 

S 

3 

z 

a 

m 

.. ...T .... .................. 

30 80 130 180 230 280 330 380 

TOTRL LENGTH (flfl) 

Appendix 57. Length-frequency histograms of yellow perch 

impinged during 1975 at the Cook Plant, southeastern Lake 

Michigan. 

A-57 
80- 

720 

640 

580 

480 

roo 

320 

210 

160 

80 

--_rr.. . . . . . . . . . . . . . . . 

w RAY 

80 

a 

80 

80 

0 

1 

TOTAL LENGTH (Rn) 

Appendix 58. 

during 1975 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of yellow perch caught 

A-50 
200 

200 

200 

200 

200 

200 

400 

m 

2ooo 

le00 

16UU 

1400 

1200 

1000 

800 

600 

400 

2wl 

1800 

1600 

1400 

1200 

loo0 

800 

600 

400 

200 

200 

200 

30 80 130 180 230 280 330 380 

TOTRL LENGTH (Mtll 

Appendix 59. Length-frequency histograms of yellow perch 

impinged during 1976 at the Cook Plant, southeastern Lake 

Michigan. 

A-59 
"E 

18 

32- 

c 

1976 

- APR - 

- a .,. 

1 

48 

32 

le 

16 

32 

c 

- OCT - 

- 

c 

IS t NOV 

Appendix 60. Length-frequency histograms of yellow perch caught 

during 1976 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-b3 
120 f: 1977 

FEB 

JUN 

720 

6ua 

480 

360 

210 

120 

120 

120 

360 

240 

120 

120 

120 

sg..................... 

DEC 

30 80 130 180 230 280 330 380 

TOT% LENGTH Ulfll 

Appendix 61. Length-frequency histograms of yellow perch 

impinged during 1977 at the Cook Plant, southeastern Lake 

Michigan. 

A-61 
L 

L 

roo 

360 

320 

280 

244 

200 

180 

120 

80 

40 

129 

80 

40 

Appendix 62. 

during 1977 field sampling at the Cook Plant, southeastern Lake 

Length-frequency histograms of yellow perch caught 

Michigan. 

A-62 
5 

H 

LL 

LL 

0 

a 

W 

a 

E= 

3 

z 

JAN 

flAY I 

2400 =I 

“L - 

4wSEP 

400 

m ................ OCT 

TOTAL LENGTH Wl) 

Appendix 63. Length-frequency histograms of yellow perch 

impinged during 1978 at the Cook Plant, southeastern Lake 

Michigan. 

A-63 
16 

8 

16 

8 

32 

24 

16 

8 

104 

96 

88 

80 

72 

64 

56 

48 

10 

32 

24 

16 

8 

16 

8 

64 

56 

48 

44 

32 

24 

16 

8 

24 

16 

0 

16 

e 

0 

TOTAL LENGTH (Rfl) 

1 

Apgendix 64. 

during 1978 field sampling at the Cook Plant, southeastern Lake 

Michigan . Length-frequency histograms of yellow perch caught 

A-64 
-i 

v) 

H 

LL 

LL 

0 

U 

w 

r= 

3 

z 

m 

L 

4w I- .. .. JUL 800 

400 

4800 

4000 

3600 E 

3200 c B88E 

28M E 

2400 L888 L 

2000 I1200 1600 E - 

L 

400 

800 

400 

80U 

400 

30 80 130 180 230 280 330 380 

TOTAL LENGTH (MI) 

Appendix 65. Length-frequency histograms of yellow perch 

impinged during 1979 at the Cook Plant, southeastern Lake 

Michigan. 

A-65 
1979 W 

80- 

i APR 

tlAY 

II 

I 

I 

L I 

c I 

BoOCT 

- 

80 - 

0 

- NOV 

60 110 160 210 260 310 360 

....' 

10 - 

TOTAL LENGTH (l'lfll 

Appendix 66. 

during 1979 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of yellow perch caught 

A-66 
4000 - 

- DEC t... 

TOTRL LENGTH [Rll) 

Appendix 67. Length-frequency histograms of yellow perch 

impinged during 1980 at the Cook Plant, southeastern Lake 

Michigan. 

A-67 
roo 11980 

I 

cn 

H 

LL 

LL 

0 

LJ 

I= 

3 

2 

a 

m 

roo 

4100 

40#1 

3600 

3200 

800 

400 

SEP 

roo 

OCT 

- 

400- - NOV 

20 70 120 170 220 270 320 

TOTAL LENGTH (MR) 

Appendix 68. 

during 1980 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of yellow perch caught 

A-68 
12000 

FIPR 

- 

- FEB 

12m - 

- MAY 

Izooo 

12000 

tzoco 

lM[w 

181,821 

- 

- JUL 

RUG 

SEP 

OCT 

................................. - 

- 

- 

- 

- 

- 

NOV 

12000 !- 

c DEC 2 

30 80 130 180 230 280 330 380 

TOTRL LENGTH (flfll 

Appendix 69. Length-frequency histograms of yellow perch 

impinged during 1981 at the Cook Plant, southeastern Lake 

Michigan . 

A-69 
8 

H 

U 

U 

0 

W 

m 

I 

a 

1 

l98* APR 

flRY 400 

RUG 400 

L 

NOV 

30 80 130 I ao 230 280 330 .................................. 

TOTAL LENGTH (fltl) 

Appendix 70. 

during 1981 field sampling at the Cook Plant, southeastern Lake 

Michigan, 

Length-frequency histograms of yellow perch caught 

A-73 
f 1982 JAN 400 

L 

400- 

400- 

- nRR ... 

OCT 4011 

.......................... 

NOV 

400 DEC 

40 90 140 190 240 290 340 390 TOTAL LENGTH 

Appendix 71. Length-frequency histograms of yellow perch 

impinged during 1982 at the Cook Plant, southeastern Lake 

Michigan. 

A-71 
TOTAL LENGTH (fftll 

tom I- E 

Appendix 72. 

during 1982 fieid sampiing at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histoZjrams of yellow perch caught 

A-72 
801 1975 

80- 

- 

- FEB 

an.-’ . 

160 

80 

I 240 

160 

80 

80 

! 

JUN 

80 

80 ~- 

- SEP r ............................ 

80 

DEC v ........... 

10 60 110 160 210 260 

TOTAL LENGTH (flfll 

Appendix 73. Length-frequency histograms of rainbow smelt 

impinged during 1975 at the Cook Plant, southeastern Lake 

Michigan. 

A-73 
a 

80 

40 

480 

380 

320 

240 c 

JUL 

3U IUU IUW 200 25G 

TOTAL LENGTH Mfl) 

Appendix 74. 

during 1975 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Lensth-frequency histograms of rainbow smelt caught 

A-74 
80 

60 

40 

20 

20 

40 

20 

140 

120 

1w 

80 

60 

40 

20 

120 

1w 

80 

60 

a 

20 

20 

40 

20 

40 

20 

20 

40 

20 

20 

40 

20 

10 60 110 160 210 260 

TOTAL LENGTH Wltl) 

Appendix 75. Length-frequency histograms of rainbow smelt 

impinged during 1976 at the Cook Plant, southeastern Lake 

Michigan. 

A-75 
96 

80 

64 

40 

32 

16 

32 

L 

48 

32 

16 

0 

so 100 150 200 250 

TOTAL LENGTH (flfll 

Appendix 76. Length-frequency histograms of rainbow smelt caught 

during 1976 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

A-75 
20 

20 

40 

20 

60 

44 

20 

40 

20 

20 

120 

100 

80 

60 

40 

20 

20 

20 

160 

140 

120 

100 

80 

60 

40 

20 

20 

20 

10 60 110 160 210 260 

TOTAL LENGTH (I'll71 

Appendix 77. Length-frequency histograms of rainbow smeit 

impinged during 1977 at the Cook Plant, southeastern Lake 

Michigan. 
1977 1 

JUN I 

520 1 

SE? 40 

80 

40 

TOTRL LENGTH (tlnl 

Appendix 78. 

during 1977 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of rainbow smelt caught 

A-78 
I 

m 

H 

LL 

LL 

0 

W 

I= 

3 

z 

a 

m 

800- 

JRN 

- . OCT 

c ............................ 

FE0 800 

tlRR 8w .. 

JUN 800 

Bw)(1 

7240 

6400 

5600 

4840 

4ooo 

32W 

2400 

1600 

800 

5600 

4800 

4000 

32W 

2400 

1600 

800 

a- 

- F SEP ................. 

NOV 800 

DEC 800 

10 60 110 160 210 260 

TOTRL LENGTH (fltll 

Appendix 79. Length-frequency histograms of rainbow smelt 

impinged during 1978 at the Cook Plant, southeastern Lake 

Michigan. 

A-79 
6M !- 

200 ? jg7* APR -. . . . .. 

400 

200 

JUN . - . . . . . . 

SEP 

OCT 

NOV 

100 150 200 250 '. .'... ..''.'.."''....*.' 

TOTAL LENGTH (RR) 

50 

Appendix 80. 

during 1978 field sampling at the Cook Plant, southeastern Lake 

Michigan . Length-frequency histograms of rainbow smelt caught 

A-33 
FEB ............................ 

800 

800 

c 

2400 

1600 

800 

8W 

L NOV 

............................ 

t.. .................... DEC 

10 60 110 160 210 260 TOTRL LENGTH (MM) 

Appendix 81. 

impinged during 1979 at the Cook Plant, southeastern Lake 

Mi c hi gan . Length-frequency histograms of rainbow smelt 

A-a1 
JUN 

TOTAL LENGTH (MMI 

Appendix 82. 

during 1979 field sampling at the Cook Plant, southeastern Lake 

Michigan, 

Length-frequency histograms of rainbow smelt caught 

A-82 
I 

v) 

H 

LL 

w8ow) 

IA 

0 

- APR .j ............. 

JRN 

4ww48000-- 

L 

- MRY ... .............. 

4ow- - RUG 

8ooo-.. ................... 

L 

L 

L 

4000 

8oM 

OCT 

41100 - 

8oM 

- NOV 

DEC 4aw 

20 70 120 170 220 

TOTRL LENGTH (flfl) 

Appendix 83. 

impinged during 1980 at the Cook Plant, southeastern Lake 

Michisan. 

Length-frequency histograms of rainbow smelt 

A-03 
I 

v, 

n 

LL. 

LL 

0 

w 

S 

3 

z 

a 

a 

10 60 110 160 210 

TOTAL LENGTH IMM) 

260 

Appendix 84. Length-frequency histograms of rainbow smelt caught 

during 1980 field sampling at the Cook Plant, southeastern Lake 

Michigan . 

A-04 
I 

v) 

H 

LL 

LL 

0 

w 

m 

z 

a 

5 

*r- - 

_.... 

HAR I .. 

............................ 

4m- - SEP 

OCT 

*- D 

4ooo- D NOV ............................ 

4moc 

DEC 

30 80 130 180 230 

TOTAL LENGTH (IYfl) 

280 

Appendix 85. Length-frequency histograms of rainbow smelt 

impinged during 1981 at the Cook Plant, southeastern Lake 

Michigan. 

A-05 
L 

SEP 200 

400 

200 

400 

2m 

0 

10 60 110 160 210 

TOTAL LENGTH (MH) 

260 

Appendix 86. Length-frequency histograms of rainbow smelt'caught 

during i981 field sampling at the Cook Plant, southeastern Lake 

Michigan . 

A-86 
JAN ...... 

FEB 

tlAR 

241 

4a 

200 

........... JUN 200 

UIO 

JUL 200 

440 

RUG 241 

440 

SEP 200 

440 

OCT 2a 

UIO 

DEC 200 

40 90 140 190 240 

TOTAL LENGTH (RMI 

Appendix 87. 

impinged during 1982 at the Cook Plant, southeastern Lake Michigan. 

Length-frequency histograms of rainbow smelt 

A-07 
l60 

320 

WIO 

320 

lW 

320 

SEP 

160 

320 

OCT la 

3211 /.............. 

NOV 

10 60 110 160 210 260 

TOTAL LENGTH (fltll 

Appendix 88. 

during 1982 field sampling at the Cook Plant, southeastern Lake 

Michigan. 

Length-frequency histograms of rainbow smelt caught 

A-88 P 

L