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1 .~ ~imf D~fifriiiil~r~r~~i~lf, fiir Minnesota Department of Natural Resources Division of Fish and Wildlife Environment Section This document is made available electronically by the Minnesota Legislative Reference Library as part of an ongoing digital archiving project. (Funding for document digitization was provided, in part, by a grant from the Minnesota Historical & Cultural Heritage Program.), PROGRESS REPORT ON THE ABBREVATED LAKE ST CROX FSH POPULATON STUDY AUGUST 8, 975 TO SEPTEMBER 9, 975 Joseph L Geis and Scott P Gustafson Aquatic Biologists February, 976

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3 ! ~ ~ ~ Minnesota Department of Natural Resources Division of Fish and Wildlife Envirorunent Section PROGRESS REPORT ON THE ABBREVATED LAKE ST CROX FSH POPULATON STUDY AUGUST 8, 975 TO SEPTEMBER 9, 975 Joseph L Geis and Scott P Gustafson Aquatic Biologists February,

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5 TABLE OF CONTENTS NTRODUCTON MATERAL AND METHODS. Trap nets.. Electro-fishing Gill nets... Shoreline Seine Scale Samples Length-weight Data RESULTS Composite Catch Trap netting Gill netting Electro- ishing Shoreline Seining Tag Returns.... DSCUSSON Muskellunge Northern Pike Walleye Sauger Smallmouth Bass Crappies White Bass Abundance ndex New Species SUM.MARY Page LTERATURE CTED APPENDX A 3. APPENDX B 3. APPENDX C 3.. APPENDX D 3. APPENDX E 3. APPENDX F ,

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7 TABLES Table 3.- Summary of age and growth data and stocking data for muskellunge collected in Lake St Croix in 975 Table 3.- Summary of age and growth data from northern pike collected in Lake St Croix in 975 Table 3.-3 Summary of the age and growth data from walleyes collected in Lake St Croix in 975 Table 3.-4 Summary of age and growth data from saugers collected in Lake St Croix in 975 Table 3.-5 Summary of age and growth data of smallmouth bass collected in Lake St Croix in 975 Table 3.-6 A summary of age and growth data of black crappies collected in Lake St Croix in 975 Table 3.-7 Summary of age and growth data of white crappies collected in Lake St Croix in 975 Table 3.-8 Summary of age and growth data of white bass collected in Lake St Croix in

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9 f ' APPENDX A 3.. Table A Table A Table A APPENDX B 3.. Table B Table B 3 - Table B 3. APPENDX C 3.. Table c Table c Table c APPENDX D 3.. Table D Table D APPENDX Composite catch of all methods of sampling, Lake St Croix, August 8 to September 9, 5 Length-frequency distribut of fish caught by in Lake St Croix August 8 to September 9, 5 Common scientific names, methods, and years of capture of fish Lake St Croix Numbers of success net sets at each ing s in Lake St Croix, 975 Lake St Croix trap netting, t 8-9, 5 ( lifts) Length-frequency distribution of fish caught by trap netting in Lake St Croix August 8-9, 975 (93 lifts) Numbers of successful gill net sets in each sampling station in Lake St Croix, 975 of Lake St Croix gill netting, September -6, 975 (43 lifts) Length-frequency distribution fish caught by gill netting Lake St Croix, September -6, 975 (43 lifts) of Lake St Croix day electro-fishing, September 4-9, 975 (5.38 hours) Length-frequency distribution of fishes caught by day electro-fishing in Lake St Croix, September,

10 APPENDX E 3. Table E 3.- Shoreline seining stations in Lake St Croix, 975 Table E 3.- Summary of Lake St Croix shoreline seining September 5,, and 9, 975 ( seine hauls) Table E 3.-3 Length-frequency distribution of fishes caught in minnow seines, Lake St Croix September 5,, and 9, 975 APPENDX F 3. Table F 3.- Abundance indices (Ab) from Lake St Croix trap net and gill net catches, Table F 3.- Abundance indices (Ab) of several species groups in Lake St Croix from combined trap net and gill net catches, Table F 3.-3 Equations of the lines and correlation coefficients for the abundance index calculations 3.-8

11 3. FSH POPULATON STUDY 3.. NTRODUCTON A comprehensive fish population study of Lake St Croix in the vicinity 0 the Allen S King Plant was initiated by the Minnesota Department of Natural Resources in 966 and completed in 97. Although fish populations appeared stable during the study and year class strengths appeared to be within normal fluctuations during the six years, continued sampling was necessary because not enough data were collected to determine long-term trends in the fishery. Sampling in alternate years was deemed acceptable, because it may take a number of years before long-term trends in the fishery become apparent. Declining populations of fish might be present in the fishery for a number of years after an additional amount of environmental stress has been added to the fishery. This report covers the sampling done on Lake St Croix in 975, the second year of assessment sampling. The report describes the sampling and analyzes the data. t includes some comparisons with the 973 assessment sampling and the comprehensive fish population study (966-97). 3.. MATERALS AND METHODS Four types of sampling gear were utilized during the 975 assessment sampling: trap nets, gill nets, electro-fishing, and minnow seine. Trap nets and gill nets were used during 973 only Trap nets A total of 93 trap net sets were completed successfully in 97 attempts. The other sets were not counted because the nets were vandalized or mis-set. 3.-9

12 Trap netting was initiated on August 8 and continued through August 9, 975 using river trap nets at stations described by Krosch (968). Nets were set at a minimum of two of the three substations in each station. Table 3.- shows the substations netted successfully. Stations 0,,, and 3 are the stations closest to the plant. n addition, a set was made on the north side of the canal where it enters the river. Four overnight sets were attempted at of these substations, except -B, Tower Point, where only one overnight set was made because of vandalism Electro-fishing A total of 5.38 hours of day-shocking was done between September 3 and September 9, 975. Two fifteen-minute runs in each of the 0 stations plus an extra eight-minute run in Station 6 and one fifteen-minute run in the discharge canal. The electro-fishing gear consisted a 30 volt Onan gaspowered DC generator mounted a foot Monarck boat. A Smith-Root type V pulse DC unit was used to regulate the electric field. The electrode arrangement consisted of a bowmounted anode, two concentric rings one-half inch stainless steel, and two stern cathodes trailing the boat. Each cathode consisted of a five-and a seven-foot length of flexible conduit tubing with lead in the bottom. Smith-Root control unit was operated at a 60 se second DC setting using a maximum se A total of 43 gill net sets were completed successfully in 44 sets from September 6, experimental gill nets as by (968). 3.-0

13 Nets were set at two of three substations in each station with two overnight sets attempted at each substation except 5-A and 8-C. The gill net set at Substation 5-A disappeared the second night, so an additional overnight set was made. Only one overnight set was attempted-at Substation 8-C. One of the other gill nets was tampered with; the marker buoy and anchor were stolen; but the net contained a large number of fish, so data from that set are included in the results Shoreline Seine A total of eleven seine hauls for young-of-the-year (yy) fish were made on three days: September 5,, and 9, 975. Nine of the seine hauls were made at locations described by Krosch (97). The shoreline seining stations are listed in Table E Scale Samples Scale samples were taken from eight species of fish including walleye, sauger, northern pike, muskellunge, white bass, smallmouth bass, black crappie, and white crappie. Scale impressions were aged independently by two workers and then verified by one of them Length-Weight Data Length-weight data were collected on thirteen species of fish: walleye, sauger, northern pike, muskellunge, white bass, smallmouth bass, black crappie, white crappie, carp, silver redhorse, golden redhorse, and shorthead redhorse. The lengthweight data and analysis will be presented in a later report because of problems in getting computer time for analysis of these data. 3.-

14 3..3 RESULTS Composite Catch A total of 48 species (5,786 fish) were collected during 975 sampling. Seven species each comprised more than 5 percent of the total catch: carp (5.3 percent), gizzard shad (3.3 percent), black crappie (0. percent), white s (9.0 percent), emerald shiner (8.5 percent), log perch (7.0 percent), and smallmouth bass (5.3 percent). An additional eight species each comprised more than one of the total catch: sauger (4.9 percent), shorthead redhorse (4. percent), white crappie (4 percent), silver redhorse (3 9, drum (3.9 percent), bluegill (.5 percent), (.4 percent), and channel catfish ( 3 species comprised 93.7 percent of all fish in the 975 sampl Table A-3. is a composite a all methods sampling. t sts each species caught and percent of total catch comprised each species. Table A-3.- is a composite length-frequency for all fish collected in the 975 sampling. A list of common and scientific names according to the American Fisheries Society (970) and methods capture of each species is found in Table A This t includes the was sampling Trap netting A total 5 species (,7 fish) were caught in 93 successf ul net lifts. Two species, (36.0 and (8.4 ), comprised.4 the.9 3.-

15 (7. percent) comprise an additional 9.l percent of the total catch. Nine species: silver redhorse (3.3 percent), shorthead redhorse (3.0 percent), Freshwater drum (.7 percent), bluegill (.8 percent), sauger (.0 percent), white sucker (0.9 percent), northern pike (0.9 percent), muskellunge (0.8 percent), and rock bass (0.8 percent) comprised an additional 5. percent of the total catch. These thirteen species comprised 98.7 percent of the total trap net catch. The silver lamprey was attached to the head of a northern pike caught in a trap net. A summary of trap net catches for 975 is shown in Table B-3.-. t includes the total number, percent composition, and catch per effort for each species of fish caught in 93 successful lifts. The length-frequency of fish caught trap netting is presented by species in Table B Gill netting A total of 30 species (,68 fish) were caught in 43 successful gill net sets. Twelve species comprised per.cent of the total catch. Gizzard shad, 8. percent of total catch, were the most abundant fish caught, almost twice the number of the next most abundant species, white bass, 4.3 percent of total catch. Sauger (.0 percent), gizzard shad and white bass collectively comprised over one-half of the total gill net catch, 54.5 percent. Four species: Freshwater drum (8.3 percent), carp (6.5 percent), silver redhorse (5.9 percent), and white crappie (5.3 percent) comprised an additional 6.0 percent of the total catch. The above seven species, plus black crappie ( 4. 4 percent) ~ shorthead redhorse ( 3. 3 percent), channel catfish (3.3 percent), walleye (.6 percent), and yellow perch (.6 percent) comprised 94.7 percent of the total gill net catch for

16 A summary of gill net catches is presented in Table C-3... t includes total nwnber, percent composition, and catch per effort for each species caught in 43 successful gill net sets. The length-frequency for all fish caught with gill nets is presented in Table C Electro-fishing A total of 37 species (,344 fish) were lected in 5.38 hours of electro-fishing during 975 sampling. Two species of darters, which had not been collected by any type of gear during the comprehensive study, were collected by electrofi in 9 One individual each, slenderhead darter and striped fantail darter were col Only twelve of 37 species collected sented more than a trace, greater total catch. Three of these: log (9.6 percent), and over 60 percent (9. 3 ), carp (9.. and bluegill ( catch for a total electro-fishing a trace the (. perch (. (0.8 ), rock bass (O 7 tnut and col le electro- shing.. electro-fishing repre of the (6.6 percent), smallwere ( 7 percent) z (7.. 4 an additional percent that comredhorse bass (0.. 6 to hours of Table o-3.-, including of D-3. ~&uj~,. are presented in percent of catch, frequency presented in 3..

17 f f t Shoreline Seining A total of 6 species (56 fish) were collected in eleven seine hauls. Eleven species comprised 94. percent of the total catch. Mimic shiners and gilt darter, two species not previously coll~cted by any method during the previous study, were collected during shoreline seining in 975. Emerald shiners were by far the most abundant species, comprising 5.9 percent of the total shoreline seine catch. Ten species: log perch (7.4 percent), smallmouth bass (6.4 percent), gizzard shad (5.7 percent), spottail shiner fs.5 percent), yellow perch (5.3 percent), silver redhorse (3. percent), shorthead redhorse (.5 percent), western sand darter (.3 percent), white bass (.4 percent), and mimic shiner ( percent) comprised an additional 40.8 percent of the catch. Table E-3.- is a summary of shoreline seining including the total number collected and percent composition. Length-frequency of fish from shoreline seining is presented in Table E Tag Returns A total of thirteen tags from tagging done during the comprehensive study were returned since the report for the 973 sampling was written. Tagged fish included nine white bass, two walleyes, one sauger, and one channel catfish. All were caught in Lake St Croix except one white bass, which was caught near Marine-on-St Croix and the channel catfish which was caught in Pool 7 of the Mississippi River. One walleye tagged on April 5, 966 in Anderson Bay was caught and released by an angler on June 8, 966 near Bayport and caught again by an angler on October 4,

18 l t 3..4 DSCUSSON Muskellunge A total of 8 muskies were collected during the 975 sampling. Scale samples from 7 of these fish included at t one fish from each of the four year classes represented by the four stockings. Examination of Minnesota Department of Natural Resources stocking records shows that muskies were stocked in Lake St Croix during 97 through 975. l were September fingerling stockings, with fish averaging ten or inches in length and ranging from seven per pound in 9 to four per pound in 974 and 975. The muskie stockings included 70 in 97,,88 in 973, 500 in 974, and 700 in 975 for a total of 3,738 muskie fingerlings during the four years. Scale samples from 7 muskies included four fish from the 975 year class, seven fish from the 974 year class, fifteen fish from the 973 year class, and one fish from the 97 year class. A summary of the 7 aged muskies and information on the muskie stockings is presented in Table 3.. J j 3.-6

19 Table 3.- Summary of age and growth data and stocking data for muskellunge collected in Lake St Croix in 975 Av. Total Number Age Year Av. Total Length Length at Av. Weight Aged Class Class Length (in. ) Range (in.) Stocking at Stocking (in.) (lb.) Oe t appears that the stockings have been successful: fish from all stockings are present. Muskies were sampled in all stations between Stillwater and the Hudson Railroad bridge. Only one muskie was taken in all of the sampling done below the Hudson Railroad bridge. t was a 4.6-inch muskie taken in a seine haul at Station 8-A, Canning Factory Point. Muskies appear to be well dispersed throughout the study area between Stillwater and the Hudson Railroad bridge and apparently disperse rapidly after being stocked. One of the fingerling muskies stocked on September 6, 975 above the Stillwater bridge, was caught at Station f-c, just above the Hudson Rai road on September 9, 975. The other three fingerling muskies collected in the 975 sampling were collected in Station 0 near 0-A on September, and the other two at 0-B on September 9, 975. The one muskie collected from the 97 year class was the same length as the average length of muskies from the 973 year class. This fish could be one of the slower growing makes from the 97 year class. Based on the growth rate of the other year classes, the larger fish from the 97 class could be expected to be recruited into the fishery during the summer of 976 and 973 year class during the summer of

20 A fish 3 pike were the 975 Scales samples these fish included seven year classes. As 3.. a (9 are not are present due to lack are large is as gamef ish in 74 were s~-~-~- ~t classes, the V+ 97 v+ 970 V success 75 scarce. Table were aged. pike " l

21 r r Walleye A total of 4 walleyes were collected by all methods during the 975 sampling. Scale samples from 4 of these fish included walleyes from six year classes. The small sample size of walleyes makes it difficult to make positive statements about this speces. Walleyes spawned successfully in 975 because yy walleyes were collected, but not in large numbers. The average length and range in lengths of walleyes comprising each age group (Table 3) indicates the year class is small and probably competing with the -slower growing members of the 973 year class. t appears that the 97 year class is overlapping and competing with the 97 year class, which is either small or was inadequately sampled@ Table 3.-3 is a summary of the 4 walleyes that were aged. Table 3.-3 Summary of the age growth data from walleyes collected in Lake St Croix in 975 No. of Fish Age Group Year Class Average Total Range in Total Length (in. ) Length (in. ) V / v , 3.-9

22 ) Sauger A saugers were during sampling.. samples fish included saugers from seven year classes. Saugers collected in the sampling were from a nwnber of s year classes, which should able to support a t.. percent of net catch in 975 compared to 50 percent gill net 973 inson, ) as!ls percent of the a month periods. The water the 73 sampling, saugers were probably in.. Consequently, made them more to nets.. account at least in part, for considerably higher catches saugers success 75 because were 974 year class of to other year larger into the into classes still and should be 3.. a some the saugers

23 Table 3.-4 Swumary of age and growth data from saugers collected in Lake St Croix in 975 r Average Total Range in Total No.. of Fish Age Group Year Class Length (in.) Length (in.) a4 so V v V Smallmouth Bass A total of 304 smallmouth bass were collected during 975 sampling. Scale samples from 76 of these fish included smallmouth bass from five year classes. The smallmouth bass had another excellent hatch in Not many scale samples were taken from yy smallmouths, but comparison of average length of yy smallmouth bass with the composite length-frequency table (Appendix A-) indicates they were present in large numbers. Smallmouth bass yy were sampled in most areas; they were collected in 8 of seine hauls and in all electro-fishing runs. Krosch (97) collected yy smallmouth bass at all seine stations and collected fair numbers during fall night shocking. Examination of the composite length-frequency table seems to indicate three year classes were collected, but Table 5 shows that five year classes were sampled. The 974 year class appears to overlap with the smaller members of the 973 year class. The larger members of the 973 year class overlap the 97 and 97 year classes, which appear to be weak or 3.. -

24 were poorly represented in our sampling.. Krosch ( 7 and 7) reported low numbers of smallmouth bass or larger, which was true during Table 3.-5 is a summary of the age collected in sampling.. data of 3.. Summary of age and of smallmouth bass collected in Lake 975 Average Total Range in Tota No. of Fish Age Group Year Class Length (in.) Length (in.) V lL 0 Black white crappies should able to produce some excelsport lent fishermen in the next two or three years, crappies dominating the catch. Both were abundant, more twice as many were sampled as were Scale samples from 43 black crappies fish from six year classes, and seven samples from 78 classes included fish

25 A total of 59 black crappies were collected during 975 sampling. The 43 fish that were aged (Table 6) included 0 yy black crappies but only two + fish. The black crappies appear to have spawned successfully in 975, but may have had poor spawning success in 974. Fish from the 974 year class appear to have grown fast, probably due to a lack of competition because of low numbers and are competing with the smaller members of the 973 year class. The 973 year class appeared to be strong and overlapped most of the 97 year class. The 97 and 970 year classes completely overlap and probably compete with each other. Table 3.-6 is a swnmary of the age and growth data for black crappies collected in 975. Table 3.-6 Summary of age and growth data of black crappies collected in Lake St Croix in 975 Average Total Range in Total No. of Fish Age Group Year Class Length (in.) Length (in.) : V v A total of 39 white crappies were collected during the 975 sampling. White crappies appear to have spawned successfully in 975, but were present in low numbers. The 974 year class of white crappies appears to be poor as did that year class of black crappies. The 973 year class of white crappies is present, but weak compared to the 973 year class of black crappies. The 97 year class of white crappies is strong and 3.-3

26 appears to be competing with the 97 year class which is weak. The 970, 969, and 968 year classes are all present, but in low numbers. probably competing with each other. All three of these year classes are Table 3.-7 is a summary of the age and growth data of white crappies collected in 975. Table 3.-7 Summary of age and growth data of white crappies collected in Lake St 975 Average Total Range in Total No. of Fish Age Group Year Class Length (in.) Length (in.) e V v l V V White Bass White bass are abundant and should support a heavy harvest for the next few years. A total of 5 white bass were collected methods during the 75 sampling. Scale samples from 85 of these white bass included fish from seven year classes. 3.-4

27 Spawning success appeared good 75 because yy white bass were abwidant.. They appear to have grown fast possibly because the 974 year class is variab and overlapped by 975 and 973 year classes.. The 973 year class is strong and should support some good fishing in the next few years. The larger members of the 97 year class appear to be competing the smaller members of the 97 year class and the larger members of the 97 year class appear to be competing with 970 year class.. The 97, 97, and 970 year class be producing some good catches anglers. The 969 class is present but numbers are low. Table 3.-8 is a summary of the age and growth from white bass col in Table 3.-8 Swnmary of age and growth data of white bass collected in Lake St Croix in 975 Average Total Range in Total No. of Fish Age Group Year Class Length (in.) Length '(in.) V v V Abwidance ndex Any increases or decreases in abundance may indicate a change in the aquatic environment which could be caused by operation of the Allen S King Plant. Since the purpose of this study is

28 to monitor the effects of the King Plant upon Lake St Croix, abundance trends are an important result of this study. Comparable catch data covering a nine-year period are avail~ able for Lake St Croix, so it is possible to look for any overall trends in abundance of fish in Lake St Croix. n an effort to determine trends in abundance of fish in Lake St Croix, abundance indices (Hile, 96 were calculated from gill net and trap net data. Catch data from fall and late summer trap netting were used to average catch rates for the period Data from period were used to coincide with the period of the ennial maintenance sampling of This average catch rate for each year was used to calculate an species, each gear, and catch was divided by expected catch to yield the abundance index. Abundance indices for gill net catches, catches, and combined gill net and trap net culated and are listed Table F-3.-. net wer(;! cal- fish, as gill net and trap net For example, abundance indices species the nets varied from 0.47 to.40, and in nets indices from 0.5 to.49. Such fluctuations are common in fish populations in Minnesota lakes (Peterson, 973). Fluctuations of a similar magnitude were reported from Woods by Heyerdahl and Smith (97). Regression lines were calculated from gill net, trap net, and combined abundance indices to determine if any long-term changes in abundance were present. A correlation was calculated for each regression line to determine if the lines indicated any trends. The correlation coefficients 3.-6

29 for the regression lines for all species indicate that in each case {gill net, trap net,.(ind combined catches) one can be confident (95 times in 00) that for all species there was no overall trend in abundance between 966 and 975. By adding the observed and expected gill net and trap net i catches for each species and then combining these figures for a group of species, abundance indices for four groups of species were calculated {Table F-3.-). These four groups were as follows: Game fish northern pike channel catfish white bass saugers walleye Panf ish rock bass bluegill white crappie black crappie Other Fish longnose gar shortnose gar gizzard shad moon eye yellow perch freshwater drum Large rough fish carp white sucker silver redhorse shorthead redhorse Regression lines and correlation coefficients were calculated for each species group. Again, there was no significant trend in abundance at the five-percent level. Thus, for the period , there was no significant overall trend in numbers of fish in Lake St Croix. Table F-3.-3 is a summary of the equations of the lines and correlation coefficients for abundance index calculations. 3.-7

30 Considering all stations, there is no indication at this time of any overall changes in fish abundance, but it is known that locally the plant affects fish concentrations. Fish are known to concentrate in water discharge from the plant at various times of the year and species may vary from time to time. Since one of the correlation coefficients was high enough to be significant at the five-percent level with two or three years more data, it should be determined by further sampling whether this correlation coefficient is actually that high. Efforts should be made to quantify the effect of the plant on local distribution of fish. The abundance index for some species is highly variable from year to year, so an effort was made to determine the cause of these fluctuations. Often the size of an adult f~sh population is directly related to abundance of young fish of that species a few years earlier. n other populations, some environmental stress may cause high mortality among adult fish. Preliminary calculations using length-frequency distributions from the entire period of the Lake St Croix fish study, in conjunction with available age and growth data from the study, indicate a relationship between the number of yy, recruits, and adult fish of that species. This may help to explain that variation in abundance indices. The preliminary calculations show promise, so this approach will be pursued and findings presented in a later report New Species The mimic shiner (Notropis volucellus), s~riped fantail darter (Etheostoma flabellare lineolaturn), gilt darter (Percina evides), and slenderhead darter (Percina phoxocephala) are four species not previously collected by any method during the King study.

31 - \ Six mimic shiners were collected in a seine haul east of sampling Station -B on September, 975. Eddy and Underhill {9 ) report that the mimic shiner is locally abundant in the St Croix River just below Taylors Falls. Mimic shiners are usually pelagic during the day and move into the littoral region at night, avoiding areas with heavy vegetation." / A single striped fantail darter was collected on September 3, 975 during a shocking run in Station 6 along the Minnesota shore just below Hudson Railroad bridge. Eddy and Underhi (9 ) report the striped darter as rare in the St Croix River below Taylors Fal t prefers cold, swift water. s may in transit because the habitat this species prefers was not where it was collected A single gi darter was collected on September 9, 975 in a seine haul north of sampling Station 5-A. Eddy and Underhill report that the gilt darter is common in the St Croix River between Taylors Falls and Lake St Croix preferring a clear water habitat. A single slenderhead darter was collected on September 8, 9 during a shocking run in Anderson Bay. Eddy and Underhill (974) report that considerable numbers of this species have been collected in the St Croix River and its tributaries

32 SUMMARY The correlation coefficient for the regression lines of abundance indices for all species caught in gill nets, trap nets, and their combined catch indicate there was no significant overall trend in abundance for all species of fish in Lake St Croix between 966 and 975. Additional sampling is necessary, because it may take several years before long-term trends in the fishery are apparent. To date, fluctuation in abundance indices appear to be related to variation in spawning success and recruitment. A total of 48 species (5,786 fish) were caught by all methods from August 8 to September 9, 975. Fifteen species: carp, gizzard shad, black crappie, white bass, emerald shiner, log perch, smallmouth bass, sauger, shorthead redhorse, white crappie, silver redhorse, drum, bluegill, yellow perch, and channel catfish (in order of abundance) comprised 93.7 percent of all fish collected in the 975 sampling

33 LTERATURE CTED on Names of pp. No. 6, Fishes, Third Press, Minneapol report on the population s NSP S to G 97. Resources University pp. Commerci Lakes Fish.. Comm the Lake St Croix Croix Environmental 7 ts at reference to the near Huot, in Minnesota

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35 APPENDX A-3. TABLE A-3. - COMPOSTE CATCH OF ALL METHODS OF SAMPLNG, LAKE ST CROX August 8 to September 9, 975 Species No. Caught % of Catch t Chestnut lamprey * Silver lamprey 6 * Lake sturgeon 6 * Longnose gar 8 * Shortnose gar 4 * Gizzard shad Goldeye 5 * Moone ye 5 * Northern pike 3 0.,5 Muskellunge Carp Emerald shiner Pugnose minnow 6 * Spottail shiner 34 o.6 Fathead minnow * Carp sucker 5 * White sucker 4 * Smallmouth buffalo 0 * Bigmouth buffalo 3 * Spotted sucker 6 * Silver redhorse River redhorse 7 * Golden redhorse 8 * Shorthead redhorse Black bullhead 3 * Yellow bullhead * Channel catfish 74.3 Bur bot 5 * Brook silversides * White bass Rock bass 35 o.6 Green sunfish * Bluegill 88.5 Smallmouth bass Largemouth bass * White crappie Black crappie w~ i3ana darter 4 *

36 Species Fantail darter Johnny darter Yellow perch Log perch Gilt darter Slenderhead darter River darter Sauger Walleye Freshwater dru.n Total * <0.. 5% TABLE A-3.- (Con't) No. Caught % of Catch * * * * *

37 TABLE A-3 e - LENGTH-FREQUENCY DSTRBUTON OF FSH CAUGHT BY ALL METHODS N LAKE ST CROX August 8 to September 9, 975 Total Length in nches Chestnut Silver Lake Long- Short-' Gizzard Goldeye lamprey lamprey sturgeor nose nose ~had g'ar gar. Mooneye Northern pike o.o o o _ Q ',..,. "".. _,., JeV -..A./a / llt-.0...l..'te -. J 'j - ; o o ?l.O -.9 ~.0...?... 9 c:3.o ? ? ;:7, ~L9 ;? ? oO n () - 4-z._n - TT"'...,"""'.c:: rp.d TOTALS W!_q 4-z._q ~ _J o L ~ = =i 3! 3 3 :> ~ 5 3 l '"? 4 l 3!

38 ~., Total Length in nches Musk ellunge Carp o.o o -? o l ? ~ ~ "7,.. J_..,,.\ - ~?,,. 0. -!!,. 3 l' l~~.j ?? ] o - io.9 75 c:; ~ ?S?l.O - L ?3-9 5 Cj 4.. o - ; ? c o UnmA~i::ur~d "Z TOTALS TABLE A-3.- {Con t) b c:!y\t'l - -!! : l 44c:; - 3_ '6. 4q ? 75 4 Emerald SpottaiJ Mimic Fathead Carp-.shiner shiner.shiner minnow sucker White Smallsucker mouth buffalo ~! c:; 6 c:;, j

39 ' r TABLE A-3.- (Con't) Total Bigmouth Spotted Silver River Golden ' Short... Black Yellow re " Length buffalo sucker red- red- red- r.ed- bullhead bullheac ca in nches horse horse horse horse o.o e>.o ? 4.o ") q ? B.o h? l? l '7 l C)~ ~ z..4 4s '7 S """'.0.' ~ l 5? ~... ~ - ~ ~- y ~ ~ B j ' iq o ~ s ? ~ 9 8.o ~ a J; l~?l.o ? o - 4.9? ;:6.. o ?8.o... -g.. 9? ? ' o i+ -- "! TT---- ~ --,.;i TOTALS -:s ' 3?l

40 Total Bur bot Brook Length silverin nches F:ides.. o ?.. O -? o o l l ,..,. " "\...,. r. ' q..../.. u A J.../.. / i4.. o - ;.. 9 l o ?l.O ?.. 9? Z ;:: ?6.9? ? ? ""' o j Unmeasured TOTALS 5 ) TABLE A-3.- (Con t) White Rock Green Bluebass bass sunfish gill 4 ~4 ~ 4 P. "i 6 h4 h l 4... ', l P. 9 ~ 4 4 '7 "i )! hh P.4 z4 qq sq? Small- tlarge- White!mouth mouth crappie Pass bass 4s 0 3 l ~ rn _j_j_l i i

41 r Total Length in nches o.o ?.O...? o o Black WesterJ crappie sand darter 7 -:s 8 -:s TABLE A-3.- (Con't) Fantail Johnny Yellow Log Gilt Slender River darter darter perch perch darter head darte::c darter.. 9 ~ , _,. ", -v r"'\ ' ~,;) "" -...,..., ;J 4.. o o ?l.O ? Unmeasur ed ~ 4 ' _L_ -.-.=-=--~ ~-:,..., ,, : i' : l! TOTALS ~

42 Total Sauger Walleye Length in nches o.o ?.0...? o '.) -z. 6.. o B.O ,....,...,..,._!.?. ~-=--!-.C:.~:U._. 5_! J 8 j..!..ti "" ,,.....,... 5.o - i4.. 9i 5 j o HL ? ? : ? o Unmeasured TOTALS 79 4 TABLE A-3.- (Con't) Freshwater drum -z,?? r '.A

43 TABLE A COMM.ON AND SCENTFC NAM.ES, METHODS AND YEARS OF CAPTURE OF FSH N LAKE ST CROX Method of Capture in 975 Years collected Electro- Minnow in previous Common Name Scientific Name** Trap net fishing Gill net seine study* w. l\.) Chestnut lamprey chthyomyzon castaneus 73 Silver lamprey chthyomyzon unicuspis. x x x 66-7, 73 American brook lamprey Lampetra lamottei 69 Lake sturgeon Acipenser fulvescens x 66-7, 73 Paddle fish Polyodon spathula Longnose gar Lepisosteus osseus x 66-7, 73 Shortnose gar Lepisosteus platostomus x x x 66-7, 73 Bow fin Amia calva American eel Anguilla rostrata 66-7, 73 ~ Gizzard shad Dorosoma cepedianum x x x x 66-7, 73 f-j Goldeye Hiodon alosiodes x 67-7, 73 Mooneye Hiodon tergisus x x x x 66-7, 73 Lake whitefish Coregonus clupeaformis 67 Brown trout Salmo trutta 66,67, 69 Brook trout Salvelinus fontinalis 66 Northern pike Esox lucius x x x x 66-7, 73 Muskellunge Esox masquinongy x x x x 7, 73 Carp Cyprinus carpio x x x x 66-7, 73 Silver chub Hybopsis storeriana 67-7, 73 Golden shiner Notemigonus crysoleucas 69 Emerald shiner Notropis atherinoides x x 67, 68, 70, 7, 73 Blacknose shiner Notropis heterolepis x 67, 7 Spottail shiner Notropis hudsonius x x 67-7 Mimic shiner Notropis volucellus x Flathead minnow Pimephales promelas x Carpsucker species Carpoides sp. x x x 66-7, 73 White sucker Catostomus commersoni x x x 66-7, 73 Smallmouth buffalo ctiobus bubalus x x 66-7, 73 * Abbreviations: 66=966; 7=97; 73=973

44 TABLE A-3.-3 (Can't) Method of CaEture in 975 Years collected Electro- Minnow in previous Common Name Scientific Name** Trap net fishing Gill net seine study* Bigmouth buffalo ctiobus cypinellus x x 66,67,69,70,73 Spotted sucker Minytrema melanops x 66-7 Silver redhorse Moxostoma anisurum x x 66-7, 73 River redhorse Moxostoma carinatum x 67-7, 73 Golden redhorse Moxostoma erythrurum x 66-7, 73 Shorthead redhorse Moxostoma macrolepidotum X x x 66-7, 73 Black bullhead ctalurus melis x x 66-7, 73 Yellow bullhead ctalurus natalis x 66-68, 70, 7 Brown bullhead ctalurus nebulosus 66 Channel catfish ctalurus punctatus x x 66-7, 73 w Flathead catfish Pylodictis olivaris 66-7, 73. Trout perch Percopsis omiscomaycus 67-7 rv Bur bot Lota lota 66,67,70,73 ~ rv Brook silverside Labidesthes sicculus x 7 White bass Morone chrysops x x x x 66-7, 73 Rock bass Ambloplites rupestris x x x 66-7, 73 Green sunfish Lepomis cyanellus x 66,69,70,7,73 Hybrid sunfish 66, 69 (green x pumpkinseed) Pumpkin seed Lepomis cibbosus 66-7 Hybrid sunfish (pumpkinseed & bluegill) Bluegill Lepomis macrochirus x x x x 66-7, 73 Smallmouth bass Micropterus dolomieui x x x x 66-7, 73 Largemouth bass Micropterus salmoides x 66-7, 73 White crappie Pomoxis annularis x x x 66-7, 73 Black crappie Pomoxis nigromaculatus X x x x 66-7, 73 Western sand darter Ammocrypta clara x owa darter Etheostoma exile 68, 70, 7 * Abbreviations: 66=966; 67=967; 68=968; 69=969; 70=970; 7=97; 73= ~...

45 TABLE A-3.-3 (Con t) Common Name Method of Capture in 975 Electrofishing Minnow Scientific Name** Trap net net seine Years collected in previous study* w.[\.) ~ w Fantail darter Johnny darter Yellow perch Log perch Gilt darter Slenderhead darter River darter Sauger Walleye Freshwater drum Etheostoma flabellare Etheostoma nigrum Perea flavescens Percina caprodes Percina evides Per~ina phoxocephala Percina shumardi Stizostedion canadense Stizostedion vitreum vitreum Aplodinotus grunniens x x x x x x x x x x x x x x x x x x x x 66, 70, , , , , 73 *Abbreviations: 66=966; 67=967; 68=968; 69=969; 70=970; 7=97; 73=973. **Scientific names are taken from the American Fisheries Scoiety, Special Publication No. 6, A List of Common and Scientific Names of Fishes from the United States and Canada, Third Edition, 970

46 .

47 APPENDX B-3.. TABLE B NUMBERS OF SUCCESSFUL TRAP NET SETS AT EACH SAMPLNG STATON N LAKE ST CROX, 975 Sampling station Number of sets r 0-A 0-B 0-C -A -A -B -C 3-A 3-C 4-A 4-C 5-A 5-B 5-C 6-A 6-B 6-C 7-A 7-B 7-C 8-A 8-B 8-C 9-A 9-C End of King Plant discharge canal, side

48 TABLE B-3.- SUMMARY OF LAKE ST CROX TRAP NETTNG, August 8-9, 975 (93 lifts) Species No. Caught % of Total Catch CPE Silver lamprey * Longnose gar * Shortnose gar * Gizzard shad * Mooneye 3 * Northern pike Muskellunge 4 o.8 Carp White sucker Smallmouth buffalo 3 * Bigmouth buffalo * Silver redhorse River redhorse * Shorthead redhorse Black bullhead * Channel catfish * White bass 0.9 Rock bass 4 o.8 Bluegill Smallmouth bass * White crappie 3 7. Black crappie Sauger 7.0 Walleye * Freshwater drum Total 7 * <0.. 5% (catch/effort)

49 Total TABLE B LENGTH-FREQUENCY DSTRBUTON OF FSH CAUGHT BY TRAP NETTNG N LAKE ST CROX, August 8-9, 975 (93 lifts) Short- Longno s nose Gizzard Mooneye orther Muskel- Carp gar ar shad ike lun e White sucker 3 l

50 TABLE B-3.-3 (Con't) Total Small- Big- Silver River Short- Black Length mouth mouth red- redhead bull.;.. redin nches buffalo buffalo horse horse horse head catfish bass bass Channel White Rock o.o ? o l ,9 7 l " l l 6" l i l l 9 l l ?l.O -.9 l ;c ? o Unmeasured TOTALS li

51 TABLE B-3.-3 (Con't) Total Small- Length Bluegill mouth White Black Sauger Walleye Drum in nches bass crappie crappie o.o ~ ti.o... i:s n.o llt.o l~).o us.o ? ? o TTnmo... p,.:i.? ~ TOTALS

52 .

53 APPENDX C-3. TABLE,,- r NUMBERS OF SUCCESSFUL GLL NET SETS N EACH SAMPLNG STATON N LAKE ST CROX, 975 Sampling Station Number of Sets 0-A 0-C -A -C -A -C 3-B 3-C 4-A 4-C 5-A 5-C 6-B 6-C 7-A 7-C 8-A 8-C 9-A 9-C End of King ~lant north side End of King ~lant south side Total discharge canal, discharge canal,

54 TABLE C-3.- SUMMARY OF LAKE ST CROX GLL NETTNG, September -6, 975 (43 lifts) Species No. Caught % of Total Catch CPE (catch/effort) Silver lamprey 3 *.070 Lake sturgeon 6 *.40 Longnose gar 4 *.093 Shortnose gar o.6.79 Gizzard shad Goldeye 5 *.. 6 Moon eye 8 *.. 86 Northern pike Muskellunge 8 *.86 Carp Carpsucker White sucker 7 *.63 Smallmouth buffalo 7 *.63 Bigmouth buffalo *.03 Spotted sucker *.047 Silver redhorse Golden redhorse o.6.7i Shorthead redhorse Black bullhead *.047 Channel catfish White bass Rock bass o.6.79 Bluegill *.03 Smallmouth bass 3 *.070 White crappie Black crappie Yellow perch Sauger Walleye Freshwater drum Total 59 * <0.5% 3.-5 '_) ~

55 . TABLE C-3.-3 LENGTH-FREQUENCY DSTRBUTON OF FSH CAUGHT BY GLL NETTNG, LAKE ST CROX, September -6, 975 (43 lifts) Total Length in nches Silver lamprey Long- Short- Lake nose nose Kizzard Northerr: Muskelsturgeor.Q'.ar gar shad Goldeve Monn eve l"'; lro l n O'A o.o ?.O o o B.o ' S L=? V - J..J. ' ll+.o o l?.o o ?l.O -.9?.0..?? o - ;4.9?5.0 - : ::-6.9?7.0 : ?8.9 ;9.0 - C-9& ?.0-3? o ~o Unmeasured i. TCYrALS l --l L 7',..... '. ~ , 3 3! l..,.., l E;oS 5 8 8! 3.-53

56 Total Leneth in nches o.. o ?.O -? o o l?.9 Carn l_!::/ V...J../ ' o 'l" 6.9 -:S o ?l.O ?.. 0 -??.. 9?3.0...? o - z4.. 9? ? ?? ? ? ? o TOTALS 40 TABLE C-3.-3 (Con't) --. L_ : ? 5 5 'L ~ c:;? R 4??? 4 7 :s?'7? Small- Big- Carp- White mouth mouth Spotted Silver Golden sucker sucke-r bu ff::i o bu ff',,, A c;,,..j.ro,... -ron"h,...,..._.,,"',..."',;i Shorthead -,.;i},,...,...c,.., -:s ,f ';Z_ Q '

57 TABLE C-3.-3 (Con't) Total Small- Length Black Channel White Rock Blue- mouth White Black Yellow in nches bullheac catfish bass bass gill bass crappie crappie perch o.o ?.. O -? o b C) b 5 b )":) ~) 5/ b f , 4 )U l?.o J..)eV -.!.Je/ r J±_ ;8 L. L L_ ? :Z,? r.; 6.o q 8.o - rn ' ? ?? c: o - ;4.. 9.?5.0 - :: :: ;:7.9 cs.o - CS.9?9.0 -? ? o TOTALS

58 Total Length in nches o.. o ?.0 -? o o ~L L:l./ V -.J...:J ' o o ?l.. O -?l..9?.0 -??.9? ? ;:4,.9 ;:> ;: 6.9? '8.0 -?~ ? o TOTALS Sauger Wall eve j C) ) TABLE C-3.-3 (Con't) Drum 3 b c.~ / L l \

59 APPENDX D-3" TABLE D-3.- SUMMARY OF LAKE ST CROX DAY ELECTRO-FSHNG, September 4-9, 975 (5.38 hours) Secies Number Cau~ht % of Total Catch CPE (catchieffort) Chestnut lamprey x Silver lamprey x Longnose gar 3 x 0.56 Shortnose gar x 0.9 Gizzard shad Mooneye x Northern pike 3 x Muskellunge x Carp Emerald shiner Spottail shiner 3 x 0.56 Carpsucker spp. x 0.37 White sucker x Spotted sucker 4 x Silver redhorse River redhorse 5 x Golden redhorse x Shorthead redhorse Yellow bullhead x Bur bot 5 x 0.93 Brook silversides x White bass 3 x Rock bass 9 o Green sunfish x Bluegill Smallmouth bass Largemouth bass o.8.04 White crappie x 0.37 Black crappie 8 o.6.49 Western sand darter x 0.9 Fantail darter x 0.9 Johnny darter x 0.37 Yellow perch Log perch Slenderhead darter x River darter x Sauger x Walleye x Total 346 x <0.. 5 /o ( ) i "'

60 Total Length in :nches o.. o ? o :Q.. O B.. O o o ?l.. O ? ? ~l.o ~ ' o , cnmeasured TOTALS TABLE D-3.- LENGHT-FREQUENCY DSTRBUTON OF FSHES CAUGHT BY DAY ELECTRO-FSHNG N LAKE ST CROX September 4-9, 975 Short- Chestnut Silver Longnose nose Gizzard MooQeye Northern Muskeltlamprey lamprey gar gar shad pike lunge.. l l l l l l l l 37 l 3 l 5 l l Carp 3 8? R 7 n n q l l l 3

61 . ~ TABLE D-3.- (Con t) Total Spot- Carp- Silver River Golden Length Emerald tail ~ucker White Spotted red..;. red- red- Shor the.ad inc :riches shiner shiner spp. sucker sucker horse horse hors~ red horse v o.. o ?.O J+.o c:,.o > o.. (S l ?R '.. '. 8) 3,, l l o ' l... us.o.. us ?l.O ? l : >.O - ~.9 < ~.o...?9. 9 ~)( ' ~> o ,... Unmeasured 5 TOTALS

62 Total Length Yellow Bur bot in nches bullhead o.o ? t.o... i~.9 ~.. o.. ':>.9 :>.. O... b ls.o... ~.. 9 l HS.O - l~ ? tl.. O - ~ c Hnmo!:!l:tn,..&:»rl TOTALS 5 TABLE D-3.- (Con't) Brook silver- White Rock Green Bluegill st de bass bass sunfish ? 3 9 si; Large- mouth bass Smallmouth bass 45 la ?