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University Micrdffilms International 300 N. Zeeb Road Ann Arbor, Ml 48106 8424402 Anderson, Robert C h arles TEMPORAL CHANGES IN RELATIVE ABUNDANCE, DISTRIBUTION AND FOOD HABITS OF FISH COLLECTED IN SHORELINE WATERS OF EAST CENTRAL LAKE MICHIGAN, NEAR LUDINGTON, MICHIGAN M ichigan State University University Microfilms International 300 N. Zeeb Road, Ann Arbor, Ml 48106 Ph.D. 1984 TEMPORAL CHANGES IN RELATIVE ABUNDANCE, DISTRIBUTION AND FOOD HABITS OF FISH COLLECTED IN SHORELINE WATERS OF EAST CENTRAL LAKE MICHIGAN, NEAR LUDINGTON, MICHIGAN By Robert C. Anderson A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Fisheries and Wildlife 1984 ABSTRACT TEMPORAL CHANGES IN RELATIVE ABUNDANCE, DISTRIBUTION AND FOOD HABITS OF FISH COLLECTED IN SHORELINE WATERS OF EAST CENTRAL LAKE MICHIGAN, NEAR LUDINGTON, MICHIGAN By Robert C. Anderson The shoreline waters of east-central Lake Michigan, near Ludington, Michigan, were intensively sampled with gill nets, seines, and sieve nets from April through November during 1976 and 1977. Comparison of catch near the Ludington Pumped Storage Power Plant (LPSPP) and a con­ trol site A.8 km to the south were made. Food habits of adult salmonids, spottail shiner, longnose dace as well as young-of-the-year alewives and spottail shiner were determined. Available food resources were sampled as well. Thirty-five species of fish were caught in shoreline waters. Seasonal changes in species composition were mainly related to spawning activity and subsequent hatching of eggs. Rainbow trout were most abundant in May as they moved along shore searching for an appropriate tributary in which to spawn. Spottail shiner and alewives were most abundant in late spring and summer as these species spawned along shore. The major fall spawner was lake trout in October. Alewife and spottail shiner adults remained nearshore through summer and early fall. Alewife took advantage of abundant zooplankton popula­ tions and emerging fish larvae for food. Spottail shiner consumed mainly terrestrial insects blown into the lake and concentrated near Robert C. Anderson shore. Both species were somewhat protected from predators since the warm water near shore acted as a barrier to large salmonids. Alewife and spottail shiner YOY remained near shore through the summer and early fall also. Alewife YOY ate mainly pelagic zooplankton such as Bosmina and Cyclops. Spottail shiner YOY ate epibenthic zoo­ plankton such as Chydorus and Alona as well as Chironomidae larvae. No consistent pattern was seen comparing sampling sites due to the dynamic nature of the fish community. The general patterns of fish movement to and from the shoreline waters derived from this study may, however, be used to modify operating modes of the LPSPP to lessen potential entrainment of fish. DEDICATION This dissertation is dedicated to Phyllis A. Anderson and our children Brian, Emily, and Becky who have shared their time and patiently provided support throughout this program. ii ACKNOWLEDGMENTS I thank Dr. Charles Liston, my graduate committee chairman, for providing the opportunity, support, and thoughtful guidance for this proj ect. This research was funded by Consumers Power Company for which I am very grateful. A special thanks is due to the Project Field Director and fellow graduate student, Dan Brazo, for his enthusiastic assistance and guidance. Completion of this program would not have been possible with­ out the assistance of the following fellow graduate students and under­ grad assistants: Joe Bohr, Steve Caddell, Dan Duffield, Joan Duffy, Bob Grahm, John Gulvas, Dave Hintze, Fred Koehler, Rick Ligman, Greg Peterson, and Fred Serchuck. Techniques of gill netting in Lake Michigan require years of experience and a great deal of ingenuity. This was provided by Mr. Leo Yeck whose patience intraining a greenhorn is greatly appreciated. I also thank the members of my graduate committee: Dr. H. E. Johnson, Dr. T. W. Porter, and Dr. E. E. Werner. Finally, I thank Jo Ann Kieman for her special efforts in typing this manuscript. iii TABLE OF CONTENTS LIST OF TABLES vi LIST OF FIGURES x INTRODUCTION 1 DESCRIPTION OF THE SAMPLING AREA 4 METHODS AND MATERIALS 9 Gill Nets Beach Seine Sieve Nets Dredging Stomach Analysis Statistical Methods 9 10 10 11 12 12 RESULTS 14 Gill Net collections Spottail Shiner Alewife Rainbow Trout Lake Trout White Sucker Brown Trout Redhorse Rainbow Smelt Longnose Dace Longnose Sucker Yellow Perch Coho Salmon Chinook Salmon 14 28 39 41 44 44 45 48 51 55 56 58 61 61 Seine Collections Alewife Spottail Shiner Rainbow Smelt Longnose Dace Chinook Salmon Lake Whitefish 66 66 75 75 76 76 76 iv Sieve Net Collections Young-Of-The-Year Fish Macroinvertebrates Zooplankton 77 77 77 83 Ekman Dredge Collections 86 Food Habit Studies Alewife and Spottail Shiner Young-Of-The-Year Adult Salmonid 86 86 92 DISCUSSION 103 SUMMARY 107 LITERATURE CITED 108 APPENDIX A 112 APPENDIX B 129 v LIST OF TABLES Page Table 1 A list of the common and scientific names of all fish collected in shoreline waters of east-central Lake Michigan, near Ludington, Michigan in order of abundance. 15 2 Total number (TN), catch per effort (CPE), standard error (SE), and total weight (TW) of each fish species captured in gill nets during April - November, 1976 and 1977. 17 3 Monthly gill net catch per effort (CPE) and standard error (SE) from April - November, 1976. 18 4 Monthly gill net catch per effort (CPE) and standard error (SE) from April - November, 1977. 20 5 Gill net catch per effort (CPE) and standard error (SE) at sunrise, midday, sunset, and midnight during April - November, 1976. 22 6 Gill net catch per effort (CPE) and standard error (SE) at sunrise, midday, sunset, and midnight during April - November, 1977. 23 7 Gill net catch per effort (CPE) and standard error (SE) by season during 1976 at stations 1 and 8. 24 8 Gill net catch per effort (CPE) and standard error (SE) by season during 1977 at stations 1, 5, and 8 (control). 25 9 Length-age frequencies gill nets during April of spottail shiner - November, 1976. captured in 37 10 Length-age frequencies gill nets during April of spottail shiner - November, 1977. captured in 37 11 Length-age frequencies of alewife captured in gill nets during April - November, 1976. 40 12 Length-age frequencies of alewife captured in gill nets during April - November, 1977. 40 vi Page 13 Length - age frequencies of rainbow trout captured in gill nets during April - November, 1976. 42 14 Length - age frequencies of rainbow trout captured in gill nets during April - November, 1977. 43 15 Length frequency of white suckers captured in gill nets during April - November, 1976 and 1977. 46 16 Sex ratio of each fish species captured in gill nets during April - November, 1976 and 1977. 47 17 Length - age frequencies of brown trout captured in gill nets during April - November, 1976. 49 18 Length - age frequencies of brown trout captured in gill nets during April - November, 1977. 50 19 Length frequency of redhorse captured in gill nets during April - November, 1976 and 1977. 52 20 Length - age frequencies of rainbow smelt captured in gill nets during April - November, 1976. 53 21 Length - age frequencies of rainbow smelt captured in gill nets during April - November, 1977. 54 22 Length frequency of longnose suckers captured in gill nets during April - November, 1976 and 1977. 57 23 Length - age frequencies of gizzard shad captured in gill nets during April - November, 1976. 59 24 Length - age frequencies of gizzard shad captured in gill nets during April - November, 1977. 60 25 Length - age frequencies of coho salmon captured in gill nets during April - November, 1976. 62 26 Length - age frequencies of coho salmon captured in gill nets during April - November, 1977. 63 27 Length - age frequencies of chinook salmon captured in gill nets during April - November, 1976. 64 28 Length - age frequencies of chinook salmon captured in gill nets during April - November, 1977. 65 Total number (TN), catch per effort (CPE), standard error (SE), and total weight (TW) of each fish species captured in beach seines during April November, 1976 and 1977. 67 vii Page Table 30 Monthly catch per effort (CPE) and standard error (SE) for beach seines from April - September, 1976. 68 31 Monthly catch per effort (CPE) and standard error (SE) for beach seines from April - October, 1977. 69 32 Diurnal catch per effort (CPE) and standard error (SE) for beach seines from April - November, 1976. 71 33 Diurnal catch per effort (CPE) and standard error (SE) for beach seines from April - November, 1977. 72 34 Catch per effort (CPE) and standard error (SE) for beach seines at station 1 and station 8 (control) from April - October, 1976. 73 35 Catch per effort (CPE) and standard error (SE) for beach seines at station 1, station 5, and station 8 (control) from April - October, 1977. 3 Density (number/m ) of young-of-the-year fish at all stations combined on each sampling date during 1977. 74 36 37 38 78 Mean total length of young-of-the-year fish captured in sieve nets on each sampling date during 1977. 79 3 Density (nr/m )of young-of-the-year captured in sieve nets by station during 1977. 80 3 39 Seasonal abundance (number/1000 m ) of Lake Michigan's shoreline drift invertebrates near Ludington, Michigan during 1977. 82 40 Monthly density (nr/m') of the major zooplankton species caught in sieve nets in shoreline waters during May through November, 1977. 84 41 Zooplankton density (nr/m ) by station and date in shoreline waters during 1977. 3 42 2 Seasonal abundance (mean number/m ) of Lake Michigan's shoreline benthic invertebrates near Ludington, Michigan, during 1977. 85 87 43 Monthly frequency of occurrence (FO), percent total number (%TN), and percent total volume (%TV) of food consumed by young-of-the-year alewives during July October, 1977. 88 44 Monthly frequency of occurrence (FO), percent total number (ZTN), and percent total volume (ZTV) of food consumed by young-of-the-year spottail shiners during July - October, 1977. 90 viii Page Table 45 Diet overlap and breadth, by taxonomic category, for young-of-the-year spottail shiner and alewife in Lake Michigan’s shoreline waters. 46 Frequency of occurrence (FO), percent total number (%TN), and percent total volume (%TV) of food organ­ isms consumed by large salmonids ( 450 mm) captured in shoreline gill nets during 1976 through 1977. ix 93 101 LIST OF FIGURES Figure Page 1 Generalized Lake Michigan shoreline profile depicting four nearshore sandbars (derived from Hands 1970). 5 2 Diagram of the Ludington Pumped Storage Project showing shoreline sampling sites 1, 5, and 8 (control) and offshore protective rock jetties and break wall. 8 3 Daily variation in gill net collections of spottail shiner and alewife in shoreline waters with respect to variations in water temperature, baro­ metric pressure, wave height, and turbidity during June and July, 1976. 29 4 Daily variation in gill net collections of spottail shiner and alewife in shoreline waters with respect to variations in water temperature, baro­ metric pressure, wave height, and turbidity during June and July, 1977. 33 5 Percent total number of food items arranged by size groups, consumed by young-of-the-year alewife and spottail shiner on July 27, 1977. 94 6 Percent total number of food items consumed by spottail shiner (SS) and alewife (AL) on sample dates in July and August, 1977. 96 Percent total number of major zooplankton species collected in shoreline waters on sample dates during July and August, 1977. 98 x INTRODUCTION During the past 120 years, the fish community of Lake Michigan has been changed through a series of man-induced perturbations. Formerly, a diverse system comprised of two large piscivores, a number of large plankton and macrobenthos feeders and a wide variety of small forage species, Lake Michigan is now dominated by five large piscivores and one small planktivorous forage species. This dramatic change occurred due to a series of events associated with man's use of the natural resources in the Great Lakes and their drainage basin. Heavy fishing pressure by a fast growing commercial fishery in concert with the success of invading species such as rainbow smelt (Osmerus mordax), sea lamprey (Petromyzon marinus), and alewife (Alosa pseudoharengus) were major factors contributing to the decline in native species populations. Deterioration of water quality due to rapid industrial development and deforestation in the Lake Michigan drainage basin also contributed to this decline. Populations of the five piscivores which dominate the food chain today are maintained through federal and state stocking programs (Christie 1974, Wells and McLain 1973, Smith 1972). Rainbow smelt were introduced and became abundant in Lake Michigan in the 1920s and 30s. The diet of young rainbow smelt, mainly inverte­ brates, placed them in competition with the lake herring (Coregonus artedii), a shallow water planktivore, resulting in a decline in herring stocks during the rainbow smelt population increase (Christie 1974). The parasitic sea lamprey spread to Lake Michigan in 1936 causing drastic reductions in two large piscivores, lake trout (Salvelinus namaycush) and burbot (Lota lota), and later reduced numbers of lake whitefish (Coregonus clupeaformis), deep-water ciscoe (Coregonus johannae), lake herring, sucker (Catostomus spp.), walleye (Stizostedion vitreum), yellow perch (Perea flavescens), and carp (Ciprinus carpio)(Wells and McLain 1973). Alewives entered the system in 1949 following this decline in the large native predator populations. The alewife, through competition for food, increased pressure on lake herring and the deep-water ciscoe group (Moffett 1956). A drastic decline in abundance of the emerald shiner (Notropis athernoides), an abundant nearshore cyprinid has also been related to alewife competition (Wells and McLain 1973). A large scale rehabilitation program for the lake trout population in Lake Michigan coordinated by the Great Lake Fishery Commission, began in 1965. An average of 2 million yearlings have been planted each year, but significant natural reproduction has not been observed. A program for the introduction of pacific salmon (Oncorhynchus spp.) into Lake Michigan began in 1966. Prior to 1970, 10.3 million coho salmon (Oncorhynchus kisutch) and 4.1 million chinook salmon (Oncorhynchus tschawytscha) young had been released. Since 1970, 2 to 3 million coho and 1 to 2 million chinook have been released annually providing a successful sport fishery. Rainbow trout (Salmo gairdneri)and brown trout (Salmo trutta) have been stocked regularly since 1960 and signi­ ficant natural reproduction has occurred (Wells and McLain 1973). These stocking programs have produced a fish community with five major piscivorous species depending mainly on the alewife as a forage base. Alewife populations, despite heavy predation, have not declined greatly in abundance and are currently suspected of causing fluctuations in the yellow perch populations through displacement from preferred spawning sites and competition for food, during early development (Wells 1977). Aspects of the aquatic community of Lake Michigan have been studied through analysis of commercial fish catches, surveys by the U.S. Fish and Wildlife Service and investigations by local universities (Wells and McLain 1973). Recently several Lake Michigan studies have been funded by utilities which own and operate power plants on the shoreline of Lake Michigan. These studies are providing further information about Lake Michigan's aquatic community (CDM Limnetics 1976). these studies focus on the nearshore zone « Several of 10 m deep) which comprises only 0.4% of the total volume of Lake Michigan yet it is the richest zone of aquatic plankton production (Beeton and Edmonson 1972). This zone also receives the majority of the domestic and industrial wastes introduced into the lake and receives the most recreational use (Smith 1970). The objective of the present study is to provide baseline data on major fish species in the shoreline waters (0-3 m deep) portion of the nearshore zone. Temporal changes in species composition, relative abundance, distribution and food habits of fish in the shoreline waters (0-3 m deep) during 1976 and 1977 are described. This report is supplemental to investigations of the effects of installing and operating a large pumped storage project on the shores of Lake Michigan (Liston and Tack 1975; Brazo and Liston 1979). Catch near the Ludington Pumped Storage Power Plant (LPSPP) is compared to the CPE at a control site in order to detect any consistent patters which may indicate avoidance of or attraction to the LPSPP. DESCRIPTION OF THE SAMPLING AREA The physical aspects of shoreline waters of large lakes are often extremely dynamic. Energy of wind generated waves released in this zone is partially absorbed by the substrate and partially transferred to turbulent alongshore currents which stir up and transport large quantities of sediment (Duane et al. 1975). Waves and alongshore current have produced a series of four persistent sandbars parallel to shore in Lake Michigan near Ludington (Hands 1970). These sandbars (Figure 1) are transported toward and away from shore as lake level and seasonal weather patterns change. Transport of sand by alongshore currents constantly covers and exposes submerged rock outcroppings, one of the few stable nearshore habitats available for colonization by benthic macroinvertebrates. This zone has high plankton production due to continual recycling of nutrients from the bottom into the water column, light penetration to the substrate and influx of nitrogen and phosphorous from the watershed (Smith 1970). Sampling for this study was restricted to the trough on the inshore side of the sandbar nearest shore. This trough fluctuated from 1-3 m in depth and usually was located 60 m from shore. Two permanent sampling sites were established for the 1976 sampling season (Figure 2), station 1 located 180 m south of the LPSPP intake channel, and station 8 located A.8 km south of the LPSPP. During 1977, another site (station 5) located 180 m north of the LPSPP intake channel was added. Substrates at stations 1 and 8 included sand and frequently exposed rock and gravel areas whereas the substrate at station 5 was sandy throughout the study. 5 Figure 1. Generalized Lake Michigan shoreline profile depicting four nearshore sandbars (derived from Hands 1970). 6 ■fSI181§ll ItSJtlfiiSii mm. 7 Figure 2. Diagram of the Ludington Pumped Storage Project showing shoreline sampling sites 1, 5, and 8 (control) and off­ shore protective rock jetties and break wall. 8 SAMPLING LUDINGTON' STATIONS Ludington Pumped Storage Project P e r* V j \ M a r q u e tte \ L a ke M ILE S RESEVOIR Sand 1 and Gravel Sand, Gravel and Pebble B ast Lake METHODS AND MATERIALS Adult and juvenile fish were sampled from April through November during 1976 and 1977. Larval fish, zooplankton, and macroinvertebrates were sampled during 1977 only. Physical parameters including water temperature, turbidity, current direction, and wave height were mea­ sured at each station prior to sampling. Climatic parameters including wind direction and barometric pressure were obtained for each sample date and time from the U.S. Coast Guard Station at Ludington. Gill Nets Variable mesh gill nets comprising seven 7.6 x 1.8 m panels of 25-, 51-, 64-, 76-, 102-, 114-, and 178-mm stretched mesh for a total length of 106.7 m were used to capture adult and juvenile fish. On each sample date, one net was set perpendicular to shore at each station. The net was attached to a stationary object on the beach, pulled out by a swimmer and anchored. Nets were set twice a week for four hours at either sunrise, midday, sunset, or midnight which was randomized using latin squares to prevent a repeating pattern. Nets were retrieved from shore and large fish (particularly catostomids and salmonids) which were still alive were immediately removed, weighed (g), measured (mm), and sexed (based on external characteristics) when possible. Scale samples were also taken and the fish were tagged with a floy tag and released. Each tag had an identification number and the address of the Ludington Laboratory printed on it so that upon recapture the tag could be returned and pertinent data added to the record for that fish. Other fish were taken to the laboratory where total length (mm), weight (g), 9 10 gonadal condition, and age (scale method) were determined for up to twenty individuals of each species captured at each station. Sub­ samples of each species were preserved for verification and possible future analysis. Stomachs were removed from the large 0 450 mm) salmonids, wrapped in cheesecloth, and preserved in a 10% formalin solution. Beach Seine Seine samples were taken monthly with a 3.1-mm square mesh, 15.2 x 1.8-m bag seine. On each sample date, 60-m seine hauls were made parallel to shore once every four hours at each station. Fish captured during seining were taken to the lab and processed in the same manner as fish captured in gill nets. Sieve Nets Three with sieve 30-m hauls were made shortly after sunset at each station nets twice each month to sample larval and juvenile fish. Drifting macroinvertebrates and zooplankton were sampled at the same time. Larval fish and macroinvertebrates were collected with a 1-mm mesh meter net with a calibrated Rigosha flow meter attached to the center of the net. A 64 micron mesh plankton net was pulled with the meter net to collect zooplankton. Nets were pulled by hand and 1/4 of the mouth of the meter net was kept above water to collect floating invertebrates. Meter net samples were fixed in 10% formalin and preserved in 70% isopropyl alcohol. Larval fish and macroinvertebrates were later sorted from samples under a lighted magnifying lens, 11 identified and counted. The number of these organisms per m 3 of water sampled was determined using the following formula: 2 Volume sampled = 0.75-^ r d where 0.75 is a correction factor for the mouth of the net held out of the water, r is the radius of the mouth of the net, and d is the distance towed. Distance towed was calculated by multiplying the number of revolutions recorded revolutions per meter. by the flow meter times the number of Calibration of the flow meter was done in a current-free indoor swimming pool. For each meter pulled, 7.57 revolutions were recorded. Larvae were examined with a binocular microscope (20-80 x mag­ nification) and identifications were based on descriptions and keys by Lippson and Moran (1974), Nelson and Cole (1975), Hogue et al. (1976), and Dorr et al. (1976). Macroinvertebrates were examined similarly and identifications were based on keys by Usinger (1956) and Borror and DeLong (1976). Zooplankton were examined with a compound microscope (100 x magnification) and identifications were made based on keys by Pennak (1978) and Torke (1974). Plankton were subsampled until at least 100 individuals of common genera were counted. Zooplankton densities were determined by the same formula used for macroinvertebrate and larval fish density determinations and dividing volumes by 9 to account for the 1/3 meter diameter of the mouth of the plankton net. Dredging Triplicate substrate samples were taken monthly at each station with an Ekman dredge (24 cm 2 area sampled) at the 1-m depth contour. Each sample was placed directly into a plastic bag, taken to the 12 laboratory, and gently washed through a 0.6-mm mesh sieve. Organisms were removed from the remaining debris and preserved in 70% isopropyl alcohol. Identifications were made with a binocular microscope (20-80 x magnification) and keys by Pennak (1978), Usinger (1956), and Borror and DeLong (1976). All taxa were counted and the number per m 2 of substrate calculated. Stomach Analysis Stomach contents of large salmonids (> 450 mm) were identified, counted, and assigned a volume based on water displacement. The entire alimentary canal of young-of-the-year (YOY) spottail shiners and alewives were removed for gut analysis. Microdissecting needles were used under 40-80 x magnification to open the gut and tease out food organisms. and enumerated. Organisms were identified to genera when possible If the number of items in the gut was large, contents were subsampled by mixing in a known volume of water (usually 10 ml) and removing 1 ml samples. Volumes of small food items such as zooplankton were estimated by entering length, width, and depth measurements into formulas for geometric configurations that approxi­ mate the shape of each taxanomic group (Kenega 1975). Length-width measurements were made with an ocular micrometer and depth was cal­ culated as a proportion of the length from ratios derived by Kenega. Statistical Methods A three-way analysis of variance was used to test for significant differences (®< = 0.1) among time (sunrise, midday, sunset, and midnight), 13 season (spring, summer, and fall) and station (1, 5, and 8) for catch per unit effort (CPE) of major fish species in gill nets. Prior to applying this test, raw data were tested for normality using a Kolmagorov-Simirnov goodness-of-fit test on the residuals (Sokal and Rohlf 1969). The data were found to be non-normally distributed and log (X + 1) transformation was found best for approaching nor­ mality. A priori contrasts were performed to determine where signi­ ficant differences occurred. Beach seine catches were not able to be normalized due to large numbers of zeros in the data. Therefore, the nonparametric Kruskal- Wallis Distribution-free test (Hollander and Wolfe 1973) was used to test for significant differences (« = 0.1) in CPE of the major fish species captured between stations 1, 5, and 8. A partial correlation analysis (Sokal and Rohlf 1969) was per­ formed to assess the relative importance of the climatic and water condition parameters in explaining changes in CPE of the major fish species captured in gill nets. RESULTS Thirty-five species of fish were collected in the shoreline waters during this study (Table 1). Of the commonly occurring near­ shore fish species in the Ludington area (Brazo and Liston 1979), only the burbot was not collected in shoreline waters. The burbot, however, does spawn along shore under the ice when sampling was not possible (Scott and Crossman 1973). Gill Net Collections During April - November, 1976 and 1977, 59 and 67 gill net sets, respectively, were made at each station. During both years, spottail shiners and alewives were the most abundant species collected; however, lake trout comprised the greatest biomass (Table 2). Total catch per effort (CPE) was greatest in June and least during April and November (Tables 3 and 4). Increased CPE during late spring and early summer corresponds with reported spawning migrations of alewives, spottail shiners, trout-perch, and yellow perch (Brazo et al. 1975; Wells 1968; Reigle 1969). On a diel basis, gill net CPE was greatest at sunrise and sunset during both years of the study (Tables 5 and 6). The effect of the Ludington Pumped Storage Project on shoreline fishes is inferred from catch comparisons between the control site (station 8) and the impact sites (stations 1 and 5) for each major species (Tables 7 and 8). 14 Table 1. A list of the common and scientific names of all fish collected in shoreline waters of east-central Lake Michi­ gan, near Ludington, Michigan in order of abundance.^- Common Names Scientific Names Alewife Alosa pseudoharengus Spottail shiner Notropis hudsonius Rainbow smelt Osmerus mordax Lake trout Salvelinus namaycush White sucker Catostomus commersoni Rainbow trout Salmo gairdneri Longnose dace Rhinichthys cataractae Brown trout Salmo trutta fario Lake whitefish Coregonus clupeaformis Redhorse Moxostoma (spp.) Yellow perch Perea flavescens Longnose sucker Catostomus catostomus Gizzard shad Dorosoma cepedianum Chinook salmon Oncorhynchus tschawytscha Coho salmon Oncorhynchus kisutch Trout-perch Percopsis omiscomaycus Carp Cyprinus carpio Johnny darter Etheostoma nigrum Round whitefish Prosopium cylindraceum Emerald shiner Notropis atherinoides Mottled sculpin Cottus bairdii Lake chub Hybopsis plumbea Northern pike Esox lucius Fathead minnow Pimephales promelas 16 Table 1. (cont'd.). Common Names Scientific Names Ninesplne stickleback Pungitius pungitius Sand shiner Notropis stramineus Pumpkinseed Lepomis gibbosus Bowf in Amea calva Bloater Coregonus hoyi Golden shiner Notemigonus crysoleucas Longnose gar Lepisosteus osseus Channel catfish Ictalurus punctatus Smallmouth bass Micropterus dolomieui Largemouth bass Micropterus salmoides Black crappie Pomoxis nigiomaculatus 1. Common and scientific names follow that of Bailey et al. 1970. Table 2. Total number (TN), catch per effort (CPE), standard error (SE), and total weight (TW) of each fish species captured in gill nets during April - November, 1976 and 1977. 1976 Species TN CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Bowf in Longnose gar Channel catfish Bloater Smallmouth bass Black crappie 2672 779 173 319 277 70 168 174 101 134 148 108 86 33 74 51 5 5 2 2 1 0 0 0 0 0 1 23.9 7.0 1.5 2.8 2.5 0.6 1.5 1.6 0.9 1.2 1.3 1.0 0.8 0.3 0.7 0.5 0.04 0.04 0.02 0.02 0.01 0.0 0.0 0.0 0.0 0.0 0.01 (4.8) (1.9) (0.3) (0.6) (0.4) (0.1) (0.3) (0.4) (0.2) (0.3) (0.4) (0.3) (0.2) (0.1) (0.1) (0.1) (0.02) (0.03) (0.01) (0.01) (0.01) (0.0) (0.0) (0.0) (0.0) (0.0) (0.01) Totals 5383 48.24 (10.6) 1977 TW(g) TN CPE (SE) 34142 19005 373580 1208005 214506 76052 386096 3361 61099 79269 17852 1692 138584 134620 93773 654 3229 510 2500 131 514 0 0 0 0 0 320 2981 504 334 279 257 170 135 124 106 93 83 65 63 57 51 39 11 4 3 0 0 2 1 1 1 1 0 16.8 2.9 1.7 1.6 1.4 0.9 0.7 0.7 0.6 0.5 0.5 0.4 0.4 0.3 0.3 0.2 0.06 0.02 0.02 0.0 0.0 0.01 0.01 0.01 0.01 0.01 0.0 (2.8) (0.7) (0.2) (0.3) (0.2) (0.2) (0.1) (0.3) (0.2) (0.2) (0.2) (0.1) (0.1) (0.06) (0.06) (0.05) (0.02) (0.01) (0.01) (0.0) (0.0) (0.01) (0.01) (0.01) (0.01) (0.01) (0.0) 38849 20286 742646 1030308 181612 168020 265998 3084 67334 45770 9541 1120 103865 261779 113332 490 3431 235 12230 0 0 4820 2640 1520 18 1510 0 2849494 5365 30.04 (5.9) 3080438 TW(g) Table 3. Monthly gill net catch per effort (CPE) and standard error (SE) from April - November, 1976. April Species CPE Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie 0.4 0.9 5.1 0.1 1.9 0.05 1.5 2.4 0.7 1.6 0.1 0.05 0.1 0.2 0.1 0.1 0.05 0.0 0.05 0.05 0.05 0.05 Totals Number of samples 15.55 19 May June July (SE) CPE (SE) CPE (SE) CPE (SE) (0.2) (0.5) (1.2) (0.07) (0.5) (0.05) (0.6) (1.0) (0.5) (1.0) (0.07) (0.05) (0.07) (0.02) (0.07) (0.07) (0.05) (0.0) (0.05) (0.05) (0.05) (0.05) 12.1 2.9 1.2 1.3 2.2 0.1 3.8 5.3 0.9 1.1 0.0 1.5 0.4 0.0 0.2 0.8 0.0 0.3 0.07 0.0 0.0 0.0 (4.8) (2.2) (0.4) (0.4) (0.9) (0.09) (1.2) (2.2) (0.6) (0.3) (0.0) (1.2) (0.2) (0.0) (0.15) (0.3) (0.0) (0.2) (0.07) (0.0) (0.0) (0.0) 90.1 18.2 0.4 0.3 1.5 0.4 1.3 0.1 0.4 1.0 1.1 2.0 0.2 1.0 0.6 1.6 0.0 0.0 0 0 0.06 0.0 0.0 (24.0) (6.0) (0.2) (0.3) (0.6) (0.2) (0.7) (0.1) (0.2) (0.4) (0.4) (0.7) (0.2) (0.4) (0.3) (0.7) (0.0) (0.0) (0.06) (0.0) (0.0) (0.0) 32.8 6.8 0.2 1.3 5.1 1.0 0.7 0.06 2.2 0.8 6.0 1.9 0.06 0.3 2.0 0.2 0.0 0.0 0.0 0.0 0.0 0.0 (7.5) (2.7) (0.1) (0.9) (1.9) (0.4) (0.3) (0.06) (0.9) (0.4) (2.2) (1.4) (0.06) (0.2) (0.5) (0.1) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (6.4) 34.17 (35.5) 61.42 (15.2) 15 • 120.26 16 (19.6) 18 Table 3.(cont'd.). August Species September CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie 19.8 19.3 0.3 3.9 3.9 2.0 1.7 0.6 1.3 2.3 1.3 0.5 0.4 0.5 0.1 0.1 0.07 0.0 0.0 0.0 0.0 0.0 (10.6) (11.7) (0.2) (1.3) (1.6) (0.8) (1.0) (0.4) (0.7) (1.2) (0.7) (0.2) (0.2) (0.3) (0.1) (0.1) (0.07) (0.0) (0.0) (0.0) (0.0) (0.0) 7.7 0.8 1.4 5.6 1.9 0.7 1.2 1.3 0.3 1.0 0.07 0.1 2.0 0.0 1.4 0.4 0.1 0.0 0.0 0.0 0.0 0.0 Totals Number of samples 58.07 (31.2) 25.97 15 CPE (SE) (4.1) (0.7) (0.4) (2.2) (0.4) (0.4) (0.3) (0.9) (0.2) (0.6) (0.07) (0.1) (0.6) (0.0) (0.4) (0.3) (0.1) (0.0) (0.0) (0.0) (0.0) (0.0) (11.8) 14 October CPE 3.3 0.1 1.0 9.4 0.6 0.2 0.4 1.1 0.3 0.6 0.0 0.5 2.7 0.0 0.07 0.07 0.07 0.0 0.0 0.0 0.0 0.0 21.4 14 November (SE) CPE (SE) (1.9) (0.1) (0.3) (2.9) (0.4) (0.1) (0.2) (1.0) (0.2) (0.4) (0.0) (0.3) (0.8) (0.0) (0.07) (0.07) (0.07) (0.0) (0.0) (0.0) (0.0) (0.0) 0.0 0.0 10.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (8.8) 12.0 (0 .0) 1 Table 4. Monthly gill net catch per effort (CPE) and standard error (SE) from April - November, 1977. April May June July Species CPE (SE) CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Sand shiner Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass 0.5 0.0 5.4 0.09 1.4 0.1 1.1 0.9 1.3 0.2 0.0 0.0 0.1 0.2 0.0 0.05 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.3) 0.0) 1.0) 0.06) 0.3) 0.07) 1.8) 0.4) 0.5) 0.1) 0.0) 0.0) 0.07) 0.1) 0.0) 0.05) 0.0) 0.0) 0.0) 0.07) 0.0) 0.0) 0.0) 0.0) 0.0) 17.6 2.5 2.1 0.7 1.5 0.6 1.0 0.2 1.3 0.0 0.04 0.7 0.04 0.7 0.0 0.3 0.1 0.0 0.2 0.0 0.0 0.04 0.0 0.0 0.0 (8.1) (1.2) (0.5) (0.3) (0.5) (0.3) (0.3) (0.1) (0.6) (0.0) (0.04) (0.4) (0.04) (0.02) (0.0) (0.1) (0.08) (0.0) (0.07) (0.0) (0.0) (0.4) (0.0) (0.0) (0.0) 51.3 9.3 0.1 0.8 2.2 0.9 0.7 0.05 0.5 0.1 0.2 0.5 0.04 0.9 0.7 0.6 0.0 0.0 0.0 0.0 0.05 0.0 0.0 0.0 0.0 (11.6) (3.9) (0.08) (0.3) (1.1) (0.3) (0.3) (0.05) (0.2) (0.1) (0.2) (0.3) (0.04) (0.3) (0.2) (0.3) (0.0) (0.0) (0.0) (0.0) (0.05) (0.0) (0.0) (0.0) (0.0) 32.3 2.3 0.0 0.8 2.2 1.3 0.5 0.0 0.7 0.7 2.0 0.2 0.0 0.3 0.5 0.2 0.0 0.0 0.0 0.0 0.04 0.0 0.04 0.04 0.0 (9.9) (0.8) (0.0) (0.6) (0.9) (0.4) (0.2) (0.0) (0.4) (0.3) (1.3) (0.1) (0.0) (0.2) (0.3) (0.1) (0.0) (0.0) (0.0) (0.0) (0.04) (0.0) (0.04) (0.04) (0.0) (19.3) 44.12 Totals Number of samples 11.44 (4.8) 22 29.62 (12.9) 26 68.94 21 (15.6) 26 Table 4.(cont'd.). August Species September October November CPE (SE) CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Sand shiner Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass 13.8 2.3 0.5 1.0 0.8 1.8 0.4 0.0 0.4 2.2 0.5 0.8 0.2 0.2 0.04 0.3 0.04 0.04 0.0 0.0 0.0 0.0 0.0 0.0 0.04 (4.1) (0.8) (0.2) (0.8) (0.2) (0.6) (0.1) (0.0) (0.3) (1.0) (0.2) (0.3) (0.1) (0.1) (0.04) (0.1) (0.04) (0.04) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.04) 11.1 1.5 1.5 3.1 1.8 1.9 1.0 4.2 0.1 0.5 0.5 0.5 0.5 0.1 0.7 0.2 0.2 0.09 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (6.1) (0.8) (0.5) (0.8) (0.7) (0.7) (0.2) (2.0) (0.1) (0.3) (0.2) (0.3) (0.2) (0.1) (0.2) (0.1) (0.1) (0.06) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) 0.6 0.4 1.9 5.6 0.5 0.3 0.6 0.2 0.0 0.3 0.1 0.1 1.1 0.0 0.3 0.0 0.09 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (0.2) (0.2) (0.5) (1.7) (0.2) (0.2) (0.2) (0.1) (0.0) (0.1) (0.1) (0.1) (0.2) (0.0) (0.1) (0.0) (0.06) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) 0.4 0.08 2.9 0.5 0.4 0.2 0.7 0.08 0.0 0.0 0.0 0.0 1.5 0.08 0.0 0.0 0.08 0.08 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (0.4) (0.08) (0.6) (0.3) (0.3) (0.1) (0.3) (0.08) (0.0) (0.0) (0.0) (0.0) (0.5) (0.08) (0.0) (0.0) (0.08) (0.08) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) Totals Number of samples 25.36 (9.1) 29.49 (4.0) 7.0 24 (13.5) 22 12.09 22 (2.9) 13 Table 5. Gill net catch per effort (CPE) and standard error (SE) at sunrise, midday, sunset, and midnight during April - November, 1976. Sunrise Species Midday Sunset Midnight CPE (SE) CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie 23.2 11.8 1.6 4.0 3.0 0.7 1.1 1.0 2.0 0.8 2.1 1.0 0.6 0.3 0.6 0.1 0.1 0.0 0.0 0.0 0.04 0.0 (7.0) (4.6) (0.7) (1.5) (0.9) (0.3) (0.4) (0.5) (0.7) (0.4) (1.4) (0.9) (0.2) (0.03) (0.3) (0.07) (0.1) (0.0) (0.0) (0.0) (0.0) (0.0) 28.8 6.7 0.8 0.3 0.3 0.04 1.6 0.2 0.1 0.2 1.0 0.0 0.4 0.0 0.4 0.04 0.0 0.0 0.0 0.04 0.0 0.0 (14.6) (5.9) (0.3) (0.2) (0.1) (0.04) (0.7) (0.2) (0.08) (0.1) (0.5) (0.0) (0.2) (0.0) (0.2) (0.04) (0.0) (0.0) (0.0) (0.04) (0.0) (0.0) 26.2 3.5 1.4 3.3 3.4 1.2 1.6 2.3 0.4 2.3 1.5 2.0 1.5 0.2 0.7 0.7 0.03 0.1 0.0 0.03 0.0 0.03 (9.4) (1.6) (0.4) (1.1) (1.0) (0.4) (0.5) (1.0) (0.2) (0.8) (0.7) (0.7) (0.5) (0.1) (0.2) (0.3) (0.03) (0.1) (0.0) (0.03) (0.0) (0.03) 17.0 6.0 2.3 3.6 3.0 0.5 1.7 2.7 1.1 1.4 0.6 0.7 0.5 0.7 0.9 0.9 0.0 0.07 0.07 0.0 0.0 0.0 (4.8) (2.2) (0.7) (1.2) (5.2) (0.2) (0.6) (1.2) (0.4) (0.4) (0.2) (0.3) (0.2) (0.3) (0.3) (0.4) (0.0) (0.07) (0.05) (0.0) (0.0) (0.0) Totals 54.04 40.92 (23.2) 52.39 (19.09) 43.74 (20.0) (18.4) Table 6. Gill net catch per effort (CPE) and standard error (SE) at sunrise, midday, sunset, and midnight during April - November, 1977. Sunrise Species Midday Sunset Midnight CPE (SE) CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass 23.5 1.9 1.0 1.9 2.0 0.9 0.5 1.1 0.9 0.4 0.3 0.4 0.3 0.2 0.4 0.1 0.1 0.02 0.02 0.02 0.0 0.0 0.0 0.0 (7.6) (1.0) (0.3) (0.6) (0.7) (0.2) (0.1) (0.8) (0.3) (0.2) (0.1) (0.2) (0.1) (0.1) (0.1) (0.04) (0.04) (0.02) (0.02) (0.02) (0.0) (0.0) (0.0) (0.0) 10.9 0.1 1.0 0.0 0.1 0.2 0.2 0.1 0.03 0.1 0.1 0.2 0.4 0.03 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 (5.4) (0.1) (0.3) (0.0) (0.1) (0.1) (0.1) (0.1) (0.03) (0.1) (0.07) (0.2) (0.2) (0.03) (0.05) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) (0.0) 21.9 4.0 2.3 2.3 1.9 1.2 1.2 0.3 0.5 0.2 1.2 0.4 0.4 0.2 0.4 0.3 0.04 0.02 0.0 0.0 0.0 0.02 0.02 0.0 (6.1) (1.9) (0.5) (0.8) (0.5) (0.3) (0.4) (0.1) (0.2) (0.1) (0.7) (0.2) (0.1) (0.1) (0.1) (0.1) (0.03) (0.02) (0.0) (0.0) (0.0) (0.02) (0.02) (0.0) 11.2 4.3 2.3 1.7 1.4 1.3 0.8 1.0 0.8 1.2 0.2 0.4 0.3 0.6 0.3 0.4 0.1 0.04 0.04 0.02 0.02 0.0 0.0 0.02 (2.7) (1.2) (0.4) (0.6) (0.3) (0.3) (0.2) (0.6) (0.3) (0.4) (0.07) (0.2) (0.03) (0.2) (0.1) (0.1) (0.05) (0.03) (0.03) (0.02) (0.02) (0.0) (0.0) (0.02) Totals Number of samples 35.96 (6.9) 38.82 (12.6) 42 13.56 33 (12.9) 46 28.48 (8.0) 56 Table 7. Gill net catch per effort (CPE) and standard error (SE) by season during 1976 at stations 1 and 8. Spring 1 Species Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon 8 CPE (SE) CPE 20.2 4.1 2.8 0.6 0.9 0.07 1.0 2.0 0.1 0.6 0.3 1.4 0.1 0.2 0.6 (6.4) (2.3) (0.9) (0.2) (0.3) (0.05) (0.3) (1.1) (0.06) (0.2) (0.1) (0.7) (0.08) (0.07) (0.3) 47.4 10.6 1.3 1.0 4.3 0.4 2.7 2.3 1.8 Totals 34.97 (13.1) Number of samples 30 1. Summer 1 (SE) (14.7) (3.2) (0.3) (0.5) (1.2) (0.1) (0.7) (0.8) (0.6) (0.6) 1,51 2.0 (0.9) 1.3 (0.8) 0.2 (0.1) 1.2 (0.2) 0.8 (0.3) 78.8 (25.0) 30 Fall 8 CPE (SE) 4.6 0.2 0.4 2.3 1.5 1.3 0.5 0.09 0.5 0.8 1.0 1.4 0.3 0.3 0.5 (2.0) (0.1) (0.2) (1.3) (0.6) (0.7) (0.2) (0.09) (0.3) (0.5) (0.5) (0.4) (0.1) (0.2) (0.4) 15.69 (7.6) 11 Indicates significantly greater CPE than other station. CPE 1 (SE) 36.8 (13.1) 27.1 (14.2) 0.08 (0.08) 2.8 (1.3) 5.8 (2.1) 2.4 (0.9) 2.3 (1.3) 0.8 (0.5) 2.4 (1.1) 3.3, (1.4) 5.6 (2.9) 0.08 (0.08) 0.3 (0.2) 0.8 (0.4) 0.3 (0.2) 90.86 (39.76) 12 CPE 8 (SE) CPE (SE) (1.1) (0.3) (0.7) (1.5) (0.4) (0.1) (0.3) (0.07) (0.0) (0.06) (0.0) (0.3) (0.4) (0.0) (0.4) 8.7 0.6 1.1 9.8 1.4 0.7 (4.3) (0.2) (0.4) (3.2) (0.5) (0.4) (0.3) (1.3) (0.2) (0.6) (0.1) (0.1) (0.9) (0.0) (0.2) 14.73 (5.63) 15 31.4 2.1 0.3 1.9 4.9 1.1 0.2 0.7 0.07 0.0 0.06 0.0 0.5 2.0 0.0 0.9 °*91 2.4 0.6, l.s} 0.3 0.1 2.7 0.0 0.6 (12.7) 14 Table 8. Gill net catch per effort (CPE) and standard error (SE) by season during 1977 at stations 1, 5, and 8 (control). Spring Stations Species 1 5 8 CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon 21.2 2.1 3.3 0.3 0.6 0.2 0.2 0.3 0.2 0.1 0.2 0.3 0.04 0.4 0.1 (5.9) (1.2) (1.0) (0.2) (0.2) (0.1) (0.1) (0.2) (0.1) (0.08) (0.1) (0.2) (0.04) (0.2) (0.06) 15.5 4.11 1.5 0.4 1.2 0.7 0.4 0.3 0.9 0.1 0.07 0.04 0.08 0.7 0.5 (6.4) (3.1) (0.4) (0.2) (0.4) (0.3) (0.2) (0.2) (0.4) (0.08) (0.05) (0.04) (0.05) (0.2) (0.3) Totals Number of samples 29.54 (9.7) 26.49 1. 26 Indicates significantly greater CPE than other stations. (12.3) 26 CPE (SE) (2.4) (1.7) (0.5) (0.3) (1.0) (1.4) (0.7) (0.3) (0.6) (0.09) (1.2) (0.4) (0.05) (0.3) (0.2) 5.1 5.2 2.0 0.7 3.6| i.*} 2.0 0.4 2.2 0.2 1.3 0.8 0.07 0.8 0.4 26.17 (11.1) 27 Table 8. (cont'd.). Summer Station 1 5 8 Species CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon 5.1 0.9 0.4 0.7 0.4 0.3 0.3 0.0 0.0 0.9 0.6 0.9 0.0 0.0 0.1 (2.5) (0.3) (0.2) (0.5) (0.2) (0.1) (0.2) (0.0) (0.0) (0.5) (0.3) (0.4) (0.0) (0.0) (0.06) 11.5, 7.6 0.4 0.0. 1.8 1.1 0.6 0.0 0.2 0.8 1.2 0.5 0.2 0.0 0.5 (3.2) (4.6) (0.2) (0.0) (1.5) (0.5) (0.2) (0.0) (0.2) (0.4) (0.9) (0.3) (0.1) (0.0) (0.3) 16.2. 3.6 0.1 2.5. 1.3} 2.6 0.4 0.0 0.8 3.0 0.4 0.1 0.1 0.4 0.4 (6.4) (1.2) (0.1) (1.7) (0.6) (1.0) (0.2) (0.0) (0.5) (1.6) (0.2) (0.1) (0.1) (0.2) (0.2) (5.3) 26.4 (12.4) 31.9 Totals Number of samples 1. 10.4 14 Indicates significantly greater CPE than other stations 13 (14.1) 14 Table 8. (cont'd.). Fall Station 1 5 8 Species CPE (SE) CPE (SE) CPE (SE) Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon 1.2 0.3 2.0 2.1 0.6 0.4 0.9 0.4 0.05 0.09 0.05 0.5 1.3 0.05 0.4 (0.6) (0.2) (0.5) (0.7) (0.3) (0.3) (0.2) (0.2) (0.05) (0.09) (0.05) (0.3) (0.3) (0.05) (0.2) 1.4 0.4 1.1 3.9 0.4 0.4 0.7 0.4 0.1 0.1 0.3 0.06 0.7 0.0 0.3 (0.5) (0.2) (0.3) (1.7) (0.2) (0.2) (0.3) (0.2) (0.09) (0.09) (0.2) (0.06) (0.2) (0.0) (0.1) 11.2, 1.5 2.7 4.6. 1.9* 2.0 0.6 4.4 0.0 0.6 0.4 0.05 0.8 0.1 0.5 (7.0) (0.9) (0.6) (1.6) (0.7) (0.7) (0.2) (2.4) (0.0) (0.3) (0.2) (0.05) (0.2) (0.07) (0.2) (4.0) 10.26 (4.3) 31.35 Totals Number of samples 1. 10.34 22 Indicates significantly greater CPE than other stations. 16 (15.1) 19 28 Spottail Shiner Spottail shiners were the most frequently caught fish species in the shoreline zone. They were most abundant in late spring with peak CPE occurring during June, 1976 and 1977 (Tables 3 and 4). This monthly pattern of abundance was similar to the pattern of monthly abundance of spawning spottail shiners (Appendix A, Tables 1 and 2). Thus, the seasonal pattern of gill net CPE reflects a shoreward spawning migration. A few individuals spawning in August and September indicated an extended spawning period. ANOVA across season, time of day, and sample site indicated no significant differences in diel CPE (Table 5 and 6); however, signifi­ cant differences in monthly CPE (the pattern noted above) and among sampling sites (Tables 7 and 8) were noted. During 1976 and 1977, CPE was significantly greater at the control site than near the LPSPP. Spottail shiners were collected exclusively in the 25-mm mesh of the net. Since no smaller mesh was used, the age-length analysis (Tables 9 and 10) is truncated at the low end (age I, 90 mm). spottail shiners were age IV and 149 mm total length. Largest During 1976, most spottail shiners were 120-129 mm while in 1977, the majority were 110119 mm. Potential relationships between changes in CPE and physical para­ meters such as water temperature, barometric pressure, wave height, and turbidity were addressed with a partial correlation analysis (Figures 3 and 4). This analysis can detect concurrent patterns of variation between the dependent variable (CPE and one of the independent variables while the others are held constant. A significant positive or negative correlation does not by itself indicate a cause and effect relationship 29 Figure 3. Daily variation in gill net collections of spottail shiner and alewife in shoreline waters with respect to variations in water temperature, barometric pressure, wave height, and turbidity during June and July, 1976. 30 (513) 400 — Spottail Shiner - - Alewife 25 20 320 CD 3 ■o 15 240 CD #+ C CD 10 160 3 80 0 (513) 400 3020 a 0) o 3 ♦ O0 0 Species 0000 - 0400 (66.18) 133.66(108.96) 11.76 (10.16) (SE) Table 33. Diurnal catch per effort (CPE) and standard error (SE) for beach seines from April - November, 1977. 0000 - 0400 0400 - 0800 0800 - 1200 1200 - 1600 1600 - 2000 CPE (SE) CPE CPE CPE CPE Alewife Spottail shiner Rainbow smelt Longnose dace Chinook salmon Rainbow trout Emerald shiner Trout-perch Yellow perch Johnny darter 9-spine stickleback Longnose sucker Mottled sculpin Lake whitefish Fathead minnow White sucker Sand shiner Golden shiner Coho salmon 46.9 4.2 3.7 4.5 0.4 0.1 0.2 1.0 0.1 1.3 (19.3) (2.8) (1.8) (1.9) (0.2) (0.1) (0.1) (0.4) (0.1) (1.2) Totals 63.75 (28.95) Species 0.05 0.05 0.3 0.5 0.1 0.05 0.2 0.0 0.1 (0.05) (0.05) (0.1) (0.4) (0.1) (0.05) (0.2) (0.0) (0.1) (SE) (SE) (SE) (SE) 2000 - 2400 CPE (SE) 1886.8 (805.0) ;2710.8 ' (2108.7) 840.7 (392.7) 13206.0 (8408.8)210.0 (92.1) 1.0 (0.06) 380.2 (276.3) 1010.8 (988.7) 230.1 (151.3) 0.9 (0.6) 0.5 (0.2) 0.5 (0.2) 0.5 (0.3) 0.2 (0.1) 11.7 (11.3) 0.6 (0.3) (0.4) 0.8 1.5 (0.8) (2.3) 0.05 (0.05) 2.7 0.3 (0.3). 0.0 (0.0) 0.5 (0.3) 2.3 0.6 (0.5) (2.1) 0.05 (0.05) 0.1 (0.1) 0.3 (0.1) 0.05 (0.05) 0.2 (0.1) 0.05 (0.05) 0.1 (0.06) 0.0 (0.0) 0.05 (0.05) 0.05 (0.05) 0.0 (0.0) 0.0 0.0 (0.0) (0.0) (0.0) 0.0 0.1 (0.1) 0.05 (0.05) 0.1 0.0 (0.0) (0.0) 0.05 (0.05) ^ 0.0 (0.1) 0.5 (0.3) 0.8 (0.4) 0.2 (0.2) 0.0 0.2 (0.2) (0.0) M 0.0 0.0 0.0 0.0 0.05 0.05 0.0 0.0 0.05 1884.0 (0.0) (0.0) (0.0) (0.0) (0.05) (0.05) (0.0) (0.0) (0.05) 0.05 0.0 0.0 1.5 0.05 0.05 0.0 0.0 0.0 (0.05) (0.0) (0.0) (1.4) (0.05) (0.05) (0.0) (0.0) (0.0) 0.0 0.0 0.05 7.9 0.0 0.0 0.0 0.05 0.0 (0.0) (0.0) (0.05) (7.8) (0.0) (0.0) (0.0) (0.05) (0.0) 0.0 0.0 0.0 1.0 0.05 0.0 0.0 0.0 0.0 (0.0) (0.0) (0.0) (1.0) (0.05) (0.0) (0.0) (0.0) (0.0) 0.05 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.05 (0.05) (0.0) (0.0) (0.3) (0.0) (0.0) (0.0) (0.0) (0.05) (806.46)3095.05(2387.81)1862.5(1391.0) 13438.45(8562.15)228.25i (109.05) Table 34. Catch per effort (CPE) and standard error (SE) for beach seines at station 1 and station 8 (control) from April - October, 1976. Station 1 Station 8 CPE (SE) CPE (SE) Alewife Spottail shiner Rainbow smelt Longnose dace Chinook salmon Rainbow trout Emerald shiner Trout-perch Yellow perch Brown trout Johnny darter 9-spine stickleback Longnose sucker Lake trout Mottled sculpin Lake whitefish Fathead minnow White sucker 50.6 3.8 0.7 0.4 1.3 0.3 0.0 0.03 0.03 0.06 0.0 0.03 (22.5) (3.1) (0.4) (0.1) (0.8) (0.1) (0.0) (0.03) (0.03) (0.06) (0.0) (0.03) 78.6 7.2 9.2 1.5 1.1 0.08 0.1 0.06 0.03 0.06 0.03 0.0 (37.2) (3.0) (4.2) (0.9) (0.5) (0.04) (0.09) (0.06) (0.03) (0.04) (0.03) (0.0) 0.03 0.03 (0.03) (0.03) 0.0 0.06 (0.0) (0.04) 0.0 (0.0) 0.03 (0.03) Totals 57.31 (27.21) 98.05 (46.13) Species Table 35. Catch per effort (CPE) and standard error (SE) for beach seines at station 1, station 5, and station 8 (control) from April - October, 1977. Station 1 Species CPE Station 5 (SE) CPE Alewife Spottail shiner Rainbow smelt Longnose dace Chinook salmon Rainbow trout Emerald shiner Trout-perch Yellow perch Brown trout Johnny darter 9-spine stickleback Longnose sucker Lake trout Mottled sculpin Lake whitefish Fathead minnow White sucker Sand shiner Golden shiner Coho salmon 6708.2 730.2 0.9 1.0 0.05 0.1 0.05 0.02 0.02 (3241.1) (390.4) (0.5) (0.5) (0.03) (0.05) (0.03) (0.02) (0.02) 0.1 0.07 0.0 (0.1) (0.04) (0.0) 1.2 0.0 0.0 0.02 0.6 0.0 0.0 0.0 0.0 0.0 (0.02) (0.5) (0.0) (0.0) (0.0) (0.0) (0.0) 0.1 5.2 0.1 0.05 0.0 0.0 0.1 Totals 7441.33 (3633.3) 1708.5 50.6 6.8 0.7 1.4 0.0 0.05 0.02 0.1 1774.92 Station 8 (SE) (778.4) (15.2) (5.9) (0.3) (1.1) (0.0) (0.03) (0.02) (0.07) CPE (SE) 2001.7 805.2 1.2 3.6 0.7 0.3 0.1 0.5 0.02 (820.8) (280.5) (0.8) (1.6) (0.3) (0.1) (0.08) (0.2) (0.02) (0.7) (0.0) (0.0) 0.2 0.0 0.03 (0.1) (0.0) (0.03) (0.06) (4.1) (0.06) (0.03) (0.0) (0.0) (0.08) 0.02 0.02 0.02 0.02 0.1 0.02 0.0 (0.02) (0.02) (0.02) (0.02) (0.06) (0.02) (0.0) (806.0) 2813.75 (1104.7) 75 the afternoon (Tables 32 and 33) prior to sunset. No significant difference between sites was noted in 1976 and 1977 (Tables 34 and 35). Spottail Shiner Seine collections of spottail shiners were much lower during 1976 than 1977 (Table 29). During 1976, the majority of spottail shiners collected were yearlings and older with peak numbers occurring in June (Table 30). In 1977, the number of yearling and older spottail shiners collected was similar to 1976; however, large numbers of YOY were collected in August and September (Table 31). In 1976, adult spottail shiners were collected mainly after dark (Table 32), while in 1977, YOY were collected close to shore primarily during daylight hours (Table 33). Spottail shiners did not demonstrate a significant preference for the control site or the impact sites (Tables 34 and 35). Rainbow Smelt Rainbow smelt were the third most abundant species in seine collections. Adults were collected mainly in the spring during their spawning run while YOY were recruited to the seine in August and remained near shore through October (Tables 30 and 31). Rainbow smelt were caught mainly after dark with greatest numbers collected near midnight (Tables 32 and 33). During 1976 and 1977, significantly more rainbow smelt were collected at the control site than the impact site just south of the plant (Tables 34 and 35). During 1977, however, the impact station north of the plant yielded more rainbow smelt than the 76 control site (Table 36). Nearly equal numbers of males and females were collected each year, however, the majority of the rainbow smelt collected were YOY. Longnose Dace Longnose dace was the fifth most abundant species collected in shoreline seine in 1976 and 1977. Peak numbers occurred in the spring during spawning (Tables 30 and 31). As with rainbow smelt, longnose dace were collected mainly after dark and were most abundant around midnight (Tables 32 and 33). A similar pattern of abundance between collections at the control site was significantly greater than the southern impact site (Tables 34 and 35). However, in 1977, more long­ nose dace were collected at the northern impact site than the other sites combined. Chinook Salmon Juvenile chinook salmon, the next most abundant species in shoreline seine collections, were collected in June shortly after being planted (Tables 30 and 31). Collections were greatest at night (Tables 32 and 33) and little difference between sites was noted (Tables 34 and 35). Lake Whitefish In 1977, a large number of YOY lake whitefish was collected in June and July at the impact site just north of the plant (Table 35) 77 possibly indicating this area is a spawning site for this species. Sieve Net Collections Young-Of-The-Year Fish Utilization of shoreline waters as a nursery area for larval and post larval stages of several fish species is demonstrated by sieve net collections (Table 36). Lake whitefish, the first species collected were seen exclusively in May. mid-June. Yellow perch followed in mid-May through Rainbow smelt were first noted in mid-May but were not seen again until mid-June and were collected in sieve nets until late August. Longnose dace were seen in one collection in August while spottail shiners and alewives were collected from mid-July through September. Sufficiently consistent samples of alewife, spottail shiner, and rainbow smelt were collected to demonstrate mean growth of these YOY fish (Table 37). Each of these species reached nearly the same size (alewives 27 mm and spottail shiners 34.3 mm) by late August. Greater numbers of alewife and spottail shiner were collected at the control site (station 8) than either of the impact sites (Table 38). Lake whitefish and yellow perch, however, were most abundant at the north impact site. Macroinvertebrates In an offshoot of this thesis research, the food habits of spottail shiner and longnose dace collected in Lake Michigan shoreline during 1975 were assessed (Anderson and Brazo 1978). The major food of both Table 36. 3 Density (number/m ) of young-of-the-year fish at all stations combined on each sampling date during 1977. Spottail Rainbow Shiner Smelt Density (N) Density (N) Lake Whitefish Density (N) Yellow Longnose Perch Dace Density (N) Density (N) Unld. Catostomidae Density (N) Unid. Larvae Density (N) Dates Alewife Density (N) 05/02 0.0 0.0 0.0 0.26 (23) 0.0 0.0 0.25 (18) 0.1 (2) 05/18 0.0 0.0 0.07 (1) 0.16 (10) 0.02 (1) 0.0 0.0 0.04 (4) 05/25 0.0 0.0 0.0 0.03 (3) 0.6 (56) 0.0 0.0 0.16 (10) 06/15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.03 (1) 06/20 0.0 0.0 0.0 0.0 0.01 (1) 0.0 0.0 0.0 07/13 0.88 (125) 0.22 (33) 0.01 (1) 0.0 0.0 0.0 0.0 0.0 07/27 0.48 (83) 0.68 (112) 0.01 (1) 0.0 0.0 0.0 0.0 0.0 08/13 0.34 (65) 0.02 (3) 0.02 (4) 0.0 0.0 0.01 (2) 0.0 0.0 08/24 0.34 (59) 0.99 (188) 0.11 (19) 0.0 0.0 0.0 0.0 0.0 09/14 0.16 (29) 0.01 (1) 0.0 0.0 0.0 0.0 0.0 0.0 09/28 1.33 (226) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Table 37. Mean total length of young-of-the-year fish captured in sieve nets on each sampling date during 1977. Spottail shiner Alewife Dates Std. (n) Length Dev. Std. (n) Length Dev. Rainbow smelt Lake whitefish Std. (n) Length Dev. Std. (n) Length Dev. 05/25 ( 51) 20.5 2.4 Yellow perch Std. (n) Length Dev. ( 50) 8.5 1.4 ( 1) 7.9 - ( 2) 4.0 .28 Longnose dace Std. (n) Length Dev 06/15 06/20 07/13 (123) 13.8 5.4 ( 30) 7.0 1.9 ( 1) 19.9 07/27 ( 82) 19.6 3.4 (112) 8.2 2.9 ( 08/13 ( 52) 17.5 4.9 ( 3) 9.4 0.8 ( 4) 25.3 6.5 08/24 ( 31) 27.6 4.0 (150) 34.3 6.1 ( 19) 31.3 1.8 09/14 ( 24) 32.3 9.0 ( 1) 48.3 - 09/28 ( 26) 31.3 4.6 1) 20.2 4.5 - 19.9 Table 38. 3 Density (nr/m ) of young-of-the-year captured in sieve nets by station during 1977. Station Species 8 1 5 Alewife 0.50 0.17 0.29 Spottail shiner 0.45 0.05 0.02 Rainbow smelt 0.02 0.01 0.02 Lake whitefish 0.01 0.02 0.04 Yellow perch 0.02 0.02 0.13 Longnose dace 0.002 0.0 0.0 Unid sucker 0.0 0.0 0.01 Unid larvae 0.05 0.03 0.11 81 species was terrestrial insects which had probably been blown into the lake and been entrained in the alongshore current. The diet overlap of these fish decreased significantly from spring to fall as did the diet breadth of the longnose dace. Anderson and Brazo (1978) attributed these results to decreased availability of common food types in the fall. In 1977, seasonal changes in composition and density of shoreline macro­ invertebrates in the alongshore drift and benthos were assessed to determine if macroinvertebrate density decreased in the fall as pre­ dicted from but analysis. Invertebrate species from nineteen orders were collected in shore­ line waters. Terrestrial insects comprised nearly 90% of invertebrate drift (Table 39). Major taxa collected were terrestrial Diptera (24.0%), terrestrial Coleoptera (9.0%), and Chironomidae adults (7.6%). Terrestrial insect parts were partially decomposed and could not be further identified. Density of drifting invertebrates was similar during 3 3 spring (2706/1000 m ) and summer (2815/1000 m ), but declined in fall 3 (630/1000 m ). Composition of drift fauna was similar throughout the year. During spring, terrestrial insect parts, Diptera, Hymenoptera, and Chironomidae comprised 96.3% of invertebrate drift. Coleoptera became important in the drift. During summer, Fall drift samples contained mainly terrestrial insect parts, Diptera, Homoptera, and Hymenoptera. Assuming that 1977 macroinvertebrate densities and composition were representative of conditions in 1975, the prediction based on food habit analysis was correct, shoreline macroinvertebrates were less abundant during fall. The source of terrestrial insects in drift in diets of shoreline fish was not directly traced. However, a phenomenon described for Swedish lakes by Norlin (1967) may apply to Lake Michigan. He found some 82 Table 39. 3 Seasonal abundance (number/1000 m ) of Lake Michigan's shoreline drift invertebrates near Ludington, Michigan during 1977. Spring (%) 5/2-6/15 n=36 Summer (%) 6/20-8/24 n=45 Fall (%) 9/14-11/8 n=36 Mean (%) Total Aquatic Invertebrates 147 (5.4) *Chironomidae 13 (0.5) *Trichoptera Ephemeroptera larvae 8 (0.3) Hydracarina 7 (0.3) Amphipoda 2 (0.1) Pelecypoda 3 (0.1) **Diptera larvae Coleoptera larvae 4 (0.2) Odonata - 303 (10.8) 85 (3.1) 29 3 53 1 - - (1.0) (0.1) (1.9) ( .1) 1 ( .1) - - - 3 (0.5) 21 (3.3) - 2 (0.3) - - 162 (7.6) 37 (1.7) 12 4 29 1 2 1 1 (0.6) (0.2) (1.4) (0.1) (0.1) (0.1) ( .1) Terrestrial Invertebrates Terrestrial insect parts Diptera Coleoptera Hymenoptera Homoptera Hemiptera Psocoptera Neuroptera Siphonoptera Araneae Orthoptera )tals * ** 1293 1005 37 161 12 5 4 5 — (47.8) 1351 (48.0) (37.1) 467 (16.6) ( 1.4) 416 (14.8) 25 ( 0.9) ( 6.0) 39 ( 1.4) ( 0.4) 5 ( 0.2) ( 0.2) 6 ( 0.2) 27 ( 1.0) ( 0.2) 4 ( 0.1) ( 0.2) — “ 407 47 24 47 54 - 2706 2815 630 Includes immature and mature life stages. Excluding Chironomidae - 3 2 (64.6) 1043 (49.1) (10.6) 509 (24.0) ( 3.8) 192 ( 9.0) 74 ( 3.5) ( 7.5) 35 ( 1.7) ( 8.6) 4 ( 0.2) 2 ( 0.1) 10 ( 0.5) 1 ( 0.1) 4 ( 0.2) ( 0.5) 1 ( 0.1) ( 0.3) - - 2123 83 terrestrial insects in the alongshore drift were washed in from shore by waves; however, the majority were blown in from upland areas. These insects were entrained in warm air currents rising from fields then released into nearby lakes as the warm air cooled near the lake creating a downdraft. Insects were then concentrated along the windward shore and entrained in the alongshore current. Thus, when lake water tempera­ ture is significantly lower than the surrounding air temperature, the lake may act as a collecting basin for airborn insects. The "collec­ tion basin" phenomenon also explains the decrease in terrestrial insects in fall compared to spring and summer. In spring, air tempera­ ture increases faster than water temperature and the lake water is colder than surrounding air, resulting in downdrafts and insect deposition. This phenomenon is generally true in summer, but not to as great a degree. During fall, however, the reverse situation occurs and lake water is warmer than the surrounding air creating updrafts rather than downdrafts. occur. In these situations, no insect deposition may Terrestrial insect density in Lake Michigan shoreline waters was much lower in the fall than in spring and summer. Zooplankton Zooplankton catch was dominated by Bosmina and Cyclops (Table 40). Bosmina were most abundant in May, July, and November. its highest density in November. Cyclops reached Diaptomus density was greatest during September through November while Daphnia density peaked in May. Alona, and Ceriodaphnia were most abundant during July. Chydorus, Comparison of total zooplankton density among stations (Table 41) showed that similar densities occurred at each station. Table 40. 3 Monthly density (nr/m ) of the major zooplankton species caught in sieve nets in shoreline waters during May through November, 1977. Species May June July Aug Sept Oct Nov Total Bosmina 1004 422 2552 335 21 85 1655 6074 Cyclops 220 48 125 85 52 62 1030 1621 Diaptomus 48 20 49 21 107 82 123 450 Daphnia 61 3 6 18 10 5 47 150 Chydorus 14 11 141 41 3 2 10 222 Alona 0 3 32 4 0 0 0 39 Ceriodaphnia 0 1 10 1 0 0 0 12 Nauplii 297 232 147 90 58 57 59 940 Totals 1644 740 3062 594 251 293 2924 9508 Table 41. 3 Zooplankton density (nr/m ) by station and date in shoreline waters during 1977. Date Station 8 Station 1 Station 5 05/18 267 636 190 05/25 374 953 970 06/15 250 156 192 06/20 296 196 410 07/13 1356 1788 1497 07/27 332 399 839 08/13 374 307 175 08/24 66 108 127 09/14 22 47 13 09/28 827 146 193 10/22 70 108 116 11/08 2058 302 566 Totals 5548 5146 5287 86 Ekman Dredge Collections The major categories of invertebrates found in dredge samples (Table 42) were Oligocheata (37.8%), Chironomidae (33.4%), and terres­ trial insect parts (13.5%). Invertebrate density decreased steadily 2 2 from a spring high of 480.4/m to a low of 99.4/m in the fall. The composition of the benthic fauna changed from predominantly aquatic species in spring to terrestrial in the fall. Chironomidae and Oligocheata, the major aquatic invertebrates throughout the year, comprised 98.6% of spring, 42.9% of summer, and 16.3% of fall benthic invertebrates. The major terrestrial invertebrate groups, insect parts, and homoptera reached their greatest densities in the summer. Food Habit Studies Alewife and Spottail Shiner Young-Of-The-Year Since young-of-the-year alewife and spottail shiner were the most abundant shoreline inhabitants, their food habits were studied to en­ hance our understanding of this zone. During 1977, in Lake Michigan shoreline waters near Ludington, Michigan, alewife YOY fed mainly on Cyclops in July, Bosmina, Cyclops, and Diaptomus in August and September. In October, Cyclops. Bosmina, and Daphnia were the major food items (Table 43). Spottail shiner consumed mainly Chydorus, Alona, and Bosmina in July, included Chironimid larvae in August, and fed almost exclusively on Bosmina during September and October (Table 44). The degree to which alewife and spottail shiner ate similar food was determined through calculation of diet overlap and breadth indices 87 Table 42. 2 Seasonal abundance (mean number/m ) of Lake Michigan's shoreline benthic invertebrates hear Ludington, Michigan, during 1977. Spring (%) 4/29, 5/19 n= 18 Summer (%) 6/24, 8/12 n=18 Fall (%) 8/31, 9/30, 10/38 n=27 Mean (%) Total Aquatic Invertebrates *Chironomidae Oligocheata Hydracarina Trichoptera larvae Coleoptera larvae Amphipoda Ostracoda Pelecypoda Isopoda 231.9 (48.3) 57.1 241.5 (50.3) 61.7 4.6 1.5 2.3 ( 0.5) 1.5 - - - - (24.1) (26.0) 16.2 (16.3) ( 2.0) ( 0.7) _ — - - - - ( 0.7) - - - - - - - - - - - - 1.5 ( 0.7) - 9.3 ( 0.3) 2.3 ( 2.3) - 82.6 93.6 1.3 0.4 0.7 0.4 4.0 1.0 0.4 (33.4) (37.8) ( 0.5) ( 0.2) ( 0.3) ( 0.2) ( 1.6) ( 0.4) ( 0.2) 33.3 9.4 2.4 11.2 4.0 1.1 1.4 0.4 (13.5) ( 3.8) ( 1.0) ( 4.5) ( 1.6) ( 0.4) ( 0.6) ( 0.2) Terrestrial Invertebrates Terrestrial insect parts **Diptera Coleoptera Horaoptera Hymenoptera Araneae Thysanoptera Neuroptera Totals - - - - - - 2.3 ( 0.5) 2.3 ( 0.5) - 480.3 81.8 15.4 1.5 4.6 1.5 1.5 1.5 1.5 (34.4) 23.1 (23.2) ( 6.5) 11.6 (11.6) ( 0.7) 4.6 ( 4.7) ( 2.0) 23.1 (23.3) ( 0.7) 6.9 ( 7.0) ( 0.7) ( 0.7) 2.3 ( 2.3) ( 0.7) - 237.2 * Includes immature and mature life stages ** Excluding Chironomidae — 99.4 247.6 Table 43. Monthly frequency of occurrence (FO), percent total number (%TN), and percent total volume (%TV) of food consumed by young-of-the-year alewives during July - October, 1977. July August FO %TN %TV FO %TN %TV Bosmina Chydorus Alona Cyclops Chironomid lar. Unid. Copepoda Daphnia Eubosmina Polyphemus Diaptomus Unid. ter. insects Herpacticoid Copepoda nauplii Leptodora 11.7 8.3 3.3 58.3 0.0 11.7 1.7 0.0 5.0 5.0 0.0 1.7 0.0 0.0 7.1 2.8 0.8 75.6 0.0 9.1 0.8 0.0 1.2 2.4 0.0 0.4 0.0 0.0 4.1 1.8 0.6 79.6 0.0 8.9 2.1 0.0 0.6 2.1 0.0 0.3 0.0 0.0 63.0 11.1 11.1 44.4 11.1 11.1 18.5 7.4 7.4 40.7 0.0 0.0 7.4 3.7 46.5 0.9 0.4 36.3 0.4 2.7 1.2 0.3 0.2 9.4 0.0 0.0 1.7 0.2 30.4 0.6 0.3 41.9 1.2 2.9 3.5 0.2 0.1 9.3 0.0 0.0 0.9 8.7 Total sample size 60 27 1026 12.4mm Food organism Number of empty stomachs 254 17 3.38mm^ 5 Table 43. (cont'd.). September Food organism October FO %TN %TV FO %TN %TV Bosmina Chydorus Alona Cyclops Chironomid lar. Unid. Copepoda Daphnia Gubosmina Polyphemus Diaptomus Unid. ter. insects Herpacticoid Copepoda nauplii Leptodora 83.3 0.0 0.0 63.3 0.0 13.3 10.0 10.0 0.0 46.7 0.0 0.1 0.0 0.0 40.3 0.0 0.0 30.9 0.0 1.0 2.3 2.0 0.0 22.9 0.0 0.7 0.0 0.0 27.7 0.0 0.0 37.7 0.0 1.2 7.3 1.4 0.0 24.0 0.0 0.7 0.0 0.0 70.0 0.0 20.0 80.0 0.0 0.0 40.0 10.0 20.0 10.0 0.0 20.0 0.0 0.0 72.2 0.0 3.5 14.4 0.0 0.0 4.9 1.5 0.2 1.6 0.0 1.7 0.0 0.0 54.6 0.0 3.7 19.3 0.0 0.0 17.3 1.2 0.1 1.9 0.0 1.9 0.0 0.0 Total sample size 30 2305 26.43mm 10 1291 Number of empty stomachs 0 0 13.47mm' Table 44. Monthly frequency of occurrence (FO), percent total number (%TN), and percent total volume (%TV) of food consumed by young-of-the-year spottail shiners during July - October, 1977. July Food organism August FO %TN %TV FO %TN %TV Bosmina Chydorus Alona Cyclops Chironomid lar. Unid. Copepoda Daohnia Eubosmina Polyphemus Diaptomus Unid. ter. insects Heroacticoid Coneooda nauolii Leotodora 30.4 66.7 39.1 1.5 10.1 7.2 1.5 1.5 1.5 0.0 0.0 0.0 0.0 0.0 13.3 43.3 40.0 0.2 1.4 1.3 0.2 0.2 0.2 0.0 0.0 0.0 0.0 0.0 10.4 38.3 43.2 0.2 5.4 1.6 0.6 0.2 0.2 0.2 0.0 0.0 0.0 0.0 58.3 33.3 33.3 0.0 50.0 0.0 0.0 8.3 0.0 0.0 8.3 0.0 0.0 0.0 28.4 23.0 16.2 0.0 24.3 0.0 0.0 5.4 0.0 0.0 2.7 0.0 0.0 0.0 14.7 12.9 11.2 0.0 58.6 0.0 0.0 2.6 0.0 0.0 tr 0.0 0.0 0.0 Total sample size 69 Number of empty stomachs 623 0 3 6.34mm 12 74 3 1.16mm' Table 44. (cont'd.). September Food organism Bosmlna Chydorus Alona Cyclops Chironomid lar. Unid. Copepoda Daphnia Eubosmina Polyphemus Diaptomus Unid. ter. Insects Herpacticold Copepoda nauplii Leptodora Total sample size Number of empty stomachs October FO %TN %TV FO %TN %TV 100.0 0.0 0.0 100.0 100.0 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 0.0 94.1 0.0 0.0 1.0 1.9 0.0 0.0 0.0 0.0 0.0 2.9 0.0 0.0 0.0 89.5 0.0 0.0 1.2 9.3 0.0 0.0 0.0 0.0 0.0 tr 0.0 0.0 0.0 100.0 0.0 0.0 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 80.0 0.0 0.0 20.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 75.0 0.0 0.0 25.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 103 0 0.86mm 1 5 0 0.04mm (Colwell and Futuyma 1971). Two overlap indices were calculated, one based on taxonomic categories of food consumed (Table 45) and another based on size of food items (Figure 5). Taxonomic overlap indices were relatively low, 0.1 through 0.34, (total possible range is 0 through 1) with higher values in August than July. Low overlap of food resulted from spottail shiners and alewife mainly consuming cladocerans and copepods, respectively (Figure 6). During August alewives ate more Bosmina than in July resulting in a greater degree of overlap. Diet overlap based on food size (0.61) was higher than diet overlap based on taxonomic category (0.1 through 0.34). degree of difference in food size There was still a marked consumed with alewives using a greater proportion of larger food items (Figure 6). Diet breadth of the spottail shiner increased faster than for alewives (Table 44) due to incorporation of benthic food items into their diet (Figure 6). Changes in composition of major zooplankton species in the near­ shore waters of Lake Michigan (Figure 7) seemed to have no impact on the composition of zooplankton species consumed by alewives or spottail shiners suggesting some degree of food selection. It is probable, however, that the decline in density of plankton late in August was partly responsible for increased overlap and diet breadth. Adult Salmonid Many fish which occur along shore are potential forage for large salmonids which move into shore mainly during spring and fall. Stomach contents of brown trout, lake trout, rainbow trout, and coho salmon collected in shoreline gill nets were examined seasonally to determine diet in this zone of Lake Michigan. 93 Table 45. Diet overlap and breadth, by taxonomic category, for young-of-the-year spottail shiner and alewife in Lake Michigan's shoreline waters. Diet overlap* July 13 July 27 Aug 13 Aug 24 0.18 0.11 0.34 0.28 1.58 1.75 2.36 1.70 3.70 1.79 4.81 2.40 8.80 13.60 10.20 20.90 12.50 20.80 34.60 26.80 Diet breadth** Spottail shiner Alewife Mean length (mm) Spottail shiner Alewife * Diet overlap = 1 - 1/2 £ /%TNAL - %TNgg 100 ** Diet breadth = 1/ £ f%TN I100/ ^ 94 Figure 5. Percent total number of food items arranged by size groups, consumed by young-of-the-year alewife and spottail shiner on July 27, 1977. HP ALEWIFE (T o tal Number Food Item s = 2 3 9 ) 80 p f~~l SPOTTAIL SHINER TOTAL (Total Number Food Item s = 5 5 8 ) 60 PERCENT NUMBER 100 40 i i 20 M w p O V E R L A P S .61 Ln m 1 0 .0 0 5 -.0 0 9 . 0 1 1 -.0 1 4 .0 3 7 -.0 3 8 FOOD ITEM SIZE (mm3) Cyclops Polyphemus Alona Chydorus Diaptomus Posming Eubosmina Chironomid Daphnia Unid. Copepoda 96 Figure 6 . Percent total number of food items consumed by spottail shiner (SS) and alewife (AL) on sample dates in July and August, 1977. H I Bosmina Chydorus Bffl Alona B l CygJops g | | Unidentified Copepoda ^ D ia p t o m u s [~]Chironomid Larvae M o t h e r s 100 pa m *ysvi 7AYA* MVA*1 oc UJ OQ 8 0 w 'X'AVA LVC.TJ i;?v* sari WAV imx a* 2 D Z vo B G tSaV ArVt _rA' < 60 - - WiVi ivTir I- o I- I- z 40 UJ o T# 4 S VR»AVi SCr» iVr« ffS* oc 20 UJ Q. 13 JUL SS AL 2 7 JUL SS AL 13 AUG SS AL 2 4 AUG SS AL 98 Figure 7. Percent total number of major zooplankton species collected in shoreline waters on sample dates during July and August, 1977. PERCENT TOTAL NUMBERS ■mm o 5’ D r* 0 3 c CD o CO 3 m 3 0) CO \D v© C h v d o ru s From the perspective of volume of food consumed, alewives repre­ sented the largest percentage of the identifiable food items found for all adult salmonids examined (Table 46). Rainbow smelt were found in brown trout and rainbow trout stomachs during spring and in lake trout stomachs during the fall. Sculpin appeared during spring in brown trout and rainbow trout stomachs and during summer in brown trout stomachs only. Terrestrial insects were noted mainly in brown trout and rain­ bow trout stomachs along with several aquatic invertebrates. It is surprising that no spottail shiners were found in the large salmonid stomachs examined since spottail shiner appear to be nearly as abundant as alewives near shore. Table 46. Frequency of occurrence (FO), percent total number (%TN), and percent total volume (%TV) of food organisms consumed by large salmonids 0450 mm) captured in shoreline gill nets during 1976 through 1977. Spring Brown trout Rainbow trout Lake trout Coho salmon Food organism FO %TN %TV FO %TN %TV FO %TN %TV F0 Alewife Sculpin Smelt Unid. fish Terr, insects 42.9 8.6 8.6 28.6 5.7 56.5 9.8 5.4 18.5 9.8 84.7 2.1 7.5 5.6 tr 15.4 3.8 3.8 7.7 74.2 16.1 3.2 6.4 79.2 1.9 9.7 1.9 28.5 70.0 95.0 66.7 28.5 30.0 5.0 Number of stomachs 35 Number of empty stomachs 8 26 18 7 3 %TN %TV 100.0 100.0 3 1 Summer Food organism FO %TN %TV FO %TN %TV F0 Alewife Sculpin Unid. fish Terr, insects 11.5 3.8 3.8 7.7 52.6 15.8 21.0 10.5 74.8 12.2 12.2 0.8 5.9 16.9 61.5 50.0 5.9 17.6 1.5 81.5 15.4 23.0 Number of stomachs 26 Number of empty stomachs 19 17 12 %TN %TV 100.0 100.0 6 3 FO %TN %TV Table 46.(cont'd.). Fall Brown trout Food organism FO Alewives 12.5 Smelt Unid. fish Fish eggs Decapoda Amphipoda Terr, insects 18.7 Chironamid lar. Trichoptera lar, Rainbow trout %TN %TV 50.0 55.4 50.0 Number of stomachs 16 Number of empty stomachs 10 44.6 FO Lake trout %TN %TV FO %TN 3.7 14.4 86.3 6.5 2.8 0.9 1.9 10.2 2.8 2.8 0.2 12.8 0.2 2.0 66.7 0.7 2.9 0.6 8.1 0.6 tr 4.1 tr tr 7.7 3.8 19.2 36.3 9.0 54.5 108 27 26 18 Coho salmon %TV FO %TN %TV 7.8 82.3 58.0 2.6 2.6 5.9 5.9 2.0 40.0 2.6 5.9 tr 38 31 DISCUSSION The shoreline waters zone of Lake Michigan does not represent an isolated portion of Lake Michigan that harbors a unique community of fish. This zone is open to emigration and immigration of many fish species. Therefore, a sampling of this zone to determine fish species composition provides merely a snapshot of a constantly changing community. The results of this study provide a series of snapshots in time and space that reveal changes in the shoreline waters fish community by season, time of day, and sample site. Concurrent monitoring of physical para­ meters, investigation of food habits, sampling available food resources, and determination of age structure, maturity, sex ratios and gonadal condition together allow formulation of theories to explain major changes in shoreline waters fish species composition. Seasonal changes in shoreline fish species composition seem to be mainly associated with spawning activity and subsequent hatching of the eggs. Most species moved near shore to spawn in a serial manner, i.e., rainbow trout and rainbow smelt in early spring, longnose dace in mid-spring, spottail shiner and alewife in late spring-summer, and lake trout, brown trout, and salmon during fall. Of these species, rainbow smelt, longnose dace, spottail shiner, alewife, and lake trout actually spawn in shoreline waters. the lake. The remaining species spawn in tributaries to Of the shoreline spawners, alewife and spottail shiner spawn at nearly the same time and their young coexist in this zone through late summer and early fall. In some lakes the fish community has evolved such that YOY of each species using shoreline waters are at different developmental stages (Keast 1978). Since YOY fish tend to change food habits frequently as they grow, diet overlap is reduced. 103 Thus, diet overlap and 104 competition for food is reduced via temporal segregation. Spottail shiner and alewife caught in this study, however, seemed to have reduced competition for food through spatial segregation. Spottail shiner YOY tended to consume more benthic zooplankton and aquatic insect larvae while alewife YOY ate zooplankton found higher in the water column. A previously abundant shoreline species, emerald shiner, which spawned in the same time period but was more palagic in nature than spottail shiners, has declined drastically since alewives entered Lake Michigan. Thus, alewife and emerald shiner were probably in direct competition for food during early development stages. Alewives were probably able to outcompete emerald shiners because they are capable of filter feeding as well as making individual strikes (Janssen 1976). Predation by adult alewife on YOY emerald shiners and on the pelagic emerald shiner eggs (Crowder 1980) probably contributed to emerald shiner decline also. Despite free access to deeper waters, the YOY alewives and spottail shiners remained in shoreline waters through summer and into fall. Particle size of the food resource may be a factor in YOY remaining near shore. Smaller zooplankton such as Bosmina and nauplii are predominant near shore in Lake Michigan while larger zooplankton such as Diaptomus predominate offshore (Evans and Hawkins 1977; Roth and Steward 1973). Zooplankton sampled during the present study were consistent with these findings as was zooplankton found in YOY alewife and spottail shiner gut analysis. It is possible, the mouth size of YOY alewife and spottail shiner prevent efficient feeding on the larger zooplankton. A second factor which may also cause most YOY to remain near shore is the warm shoreline water temperature during August and early September. This factor was substantiated by declines in YOY abundance when upwellings 105 caused warm water masses to move away from shore. Alewife and spottail shiner YOY fish did not, however, remain in shoreline waters after dark to the extent they did during daylight hours. Low CPE after dark indicated that many YOY moved to deeper water. Janssen (1976 and 1978) reported that adult alewives dispersed after dark in nearshore waters to feed. It is possible that their young followed the same pattern and dispersed throughout the nearshore zone at night resulting in a lower CPE in shoreline waters. Keast (1978), Helfman (1978), and Werner et al. (1977) also found that YOY fish tend to remain in shallow water in temperate freshwater lakes. They hypothesized this behavior functioned in reducing predation and intraspecific competition. In Lake Michigan, as is discussed in the next paragraph, adult alewife and spottail shiner do not move offshore until fall; thus, the potential for intraspecific competition and predation still exists. Alewife age structure, however, did indicate that few age 11 individuals used shallow waters; thus, possibly reducing intraspecific competition somewhat. Mid and late spring spawning adults remained abundant in shoreline waters through the summer probably for similar reasons as the YOY (food availability and preferred water temperature). Wells (1968) reported that spottail shiner and alewife moved shoreward in spring as water temperature near shore increased and remained near shore until nearshore water temperature declined in fall. Alewife adults were found to feed heavily on YOY fish in August and September (Webb and McComish 1974) while spottail shiner and longnose dace adults fed extensively on terrestrial insects which accummulated along shore during summer. The warm waters nearshore also may have provided a barrier to major shore­ ward movements of piscivores; thus, to some degree, protecting adult 106 alewives, spottail shiners, and longnose dace from predation. Lake trout was the only abundant fall shoreline spawner. These fish moved shoreward in September and October after the majority of alewives and spottail shiners had moved offshore. Most individuals were caught after sunset when wave action was minimal. No consistent pattern was seen in comparing the control station to the impact stations. The dynamic nature of the fish community near­ shore makes assessment of the impact of a facility such as the LPSPP by comparing stations very difficult. A better approach may be to use the general patterns of fish movements into the shoreline waters derived from this study to alter water intake periods. For example, fewer lake trout may be entrained in the LPSPP reservoir if water in­ take were curtailed on calm nights in September and October. Pumping could also be curtailed during peak rainbow trout spawning times in the spring to decrease entrainment of this species. During August, daytime pumping should be avoided to decrease entrainment of large numbers of YOY that are concentrated nearshore. Further studies of the shoreline waters would allow better defini­ tion of behavior patterns and their relation to physical parameters. Predictive models could then be formulated to allow shoreline facilities such as the LPSPP to reduce entrainment of fish with minimal reduction in operating time. SUMMARY The shoreline waters (0-3 m) of Lake Michigan near Ludington, Michigan, were sampled with variable mesh gill nets, seines, and sieve nets to obtain a representation of the fish species composition during spring, summer, and fall. Food resources were sampled and gut analysis performed to understand how fish use this zone. Thirty-five species of fish were caught during April through November, 1976 and 1977. Spottail shiner and alewife dominated the catch from late May through early September. Rainbow trout were the most abundant species caught in April and November while lake trout were the most abundant in October. Gonadal condition of these fish revealed that many adults of each species were in spawning condition. Alewife and spottail shiner young-of-the-year (YOY) were initially caught in sieve nets in mid-July and dominated seine collections in August and September. Food habit studies of YOY alewife and spottail shiner indicated that spottail shiner ate epibenthic foods such as Chydorus, Alona, and Chironomidae larvae. Alewife ate more pelagic foods such as Bosmina and Cyclops. Adult alewife food habits were not studied; however, spottail shiner and longnose dace adults were both found to eat terrestrial insects which accummulate in the shoreline waters. Adult salmonid sto- maches were examined to determine which shoreline species were most susceptible to predation. Alewives were by far the most frequently consumed prey by salmonids. 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Life history studies of the longnose sucker, Catostomus catostomus and the white sucker, Catostomus commersoni, in nearshore eastern Lake Michigan. M. S. Thesis. Michigan State Univ. 56 pp. Llppson, A. J. and R. L. Moran. 1974. Manual for identification of early developmental stages of fishes of the Potomac River estuary. Maryland DNR. PPSP-MP-13:282 pp. Liston, (2. R. and P. I. Tack. 1975. A study of the effects of installing and operating a large pumped storage project on the shores of Lake Michigan. 1973. Annl. Rep. to Consumers Power Co. Dept. Fish, and Wildl., Mich. State Univ. 113 pp. Moffett, J. W. 1956. Recent changes in the deep-water fish populations of Lake Michigan. Trans. Am. Fish. Soc. 86:393-408. Nelson, ID. D. and R. A. Cole. 1975. The distribution of larval fishes along the western shore of Lake Erie at Monroe, Michigan. Mich. State Univ. Institute of Water Research Technical Rep. No. 32.4:66 pp. Norlin, ii. 1967. Terrestrial insects in lake surfaces. Their availability and importance as fish food. Rep. Inst. Freshw. Res. Drottningholm 47:39-55. Pennak, II. W. 1978. Fresh-water Invertebrates of the United States, 2nd Ed. John Wiley and Sons, New York, New York, 803 pp. Reigle, fI. J., Jr. 1969. Bottom trawl explorations in Green Bay of Lake Michigan, 1963-1965. U. S. Dept. Int. Bur. Com. Fish. Circ. No. 297. 14 pp. Roth, J. C. and J. A. Stewart. 1973. Nearshore zooplankton of south­ eastern Lake Michigan, 1972. Proc. 16th Conf. Great Lakes Res., Int. Assoc. Great Lakes Res., 1973:132-142. Scott, W. B. and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Res. Bd. of Canada, Ottawa. Bull. 184. 966 pp. Smith, S. H. 1970. Species interactions of the alewife in the Great Lakes. Trans. Am. Fish. Soc. 99:754-765. Ill 1972. Factors of ecological succession in oligotrophic fish communities of the Laurentian Great Lakes. J. Fish. Res. Board Can. 29:717-730. Sokal, R. R. and F. J. Rohlf. 1969. Biometry. The principles and practice of statistics in biological research. W. H. Freeman and Co., San Francisco, California. 776 pp. Torke, B. G. 1974. An illustrated guide to the identification of the plankton crustacea of Lake Michigan with notes on their ecology. Center for Great Lakes Studies, The University of Wisconsin, Milwaukee Press. 65 pp. Trautman, M. B. 1957. The fishes of Ohio. Columbus. 683 pp. Ohio State Univ. Press, Usinger, R. L. 1956. Aquatic insects of California. California Press. Los Angeles. 508 pp. University of Webb, D. A. and T. S. McComish. 1974. Food habits of adult alewives in Lake Michigan near Michigan City, Indiana in 1971 and 1972. Ind. Acad. Sci. 33:179-184. Wells, L. 1968. Seasonal depth distribution of fish in southeastern Lake Michigan. Fish. Bull. 67(1):1-15. 1977. Changes in yellow perch populations of Lake Michigan, 1954-1975. Great Lakes Fish. Lab., U. S. Fish, and Wildl. Serv. Unpublished manuscript. 27 pp. and A. L. McLain. 1973. Lake Michigan. Man's effects on native fish stocks and other biota. Great Lakes Fishery Comm. Tech. Rep. No. 20. 55 pp. Werner, E. E. 1977. Species packing and niche complementarity in three sunfishes. Amer. Natur. 111:553-578. APPENDIX A Table 1. Monthly maturity and gonadal condition of each fish species captured in gill nets during 1976. April Maturity Species Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Gonadal Condition Immature Mature Green Ripe Partly Spent Spent Abnormal 0 2 20 0 5 0 5 0 1 0 0 0 2 0 0 0 0 0 0 0 0 0 7 16 77 2 31 1 24 37 13 31 2 1 0 4 2 2 2 0 1 1 1 1 7 18 40 2 20 1 29 3 7 30 2 1 2 3 2 2 1 0 0 1 1 1 0 0 50 0 10 0 0 33 1 1 0 0 0 1 0 0 0 0 1 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 5 0 0 1 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Table 1. (cont’d.). Gonadal Condition Maturity Species Mature Green 0 14 6 0 16 2 4 0 6 0 0 0 ■1 0 3 0 0 0 0 0 0 0 75 10 12 19 17 0 53 51 8 16 0 15 5 0 0 12 0 5 1 0 0 0 67 24 9 19 23 2 57 0 8 16 0 15 Ripe 7 0 1 0 0 0 0 22 0 0 0 0 6 0 0 3 7 0 3 0 0 0 0 0 0 5 0 2 1 0 0 0 Partly Spent 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Spent Abnormal 1 0 8 0 10 0 0 28 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 113 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Goho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Immature Table 1. (cont'd.). June Maturity Species Immature Mature Green Ripe 0 25 4 0 12 1 2 0 6 0 1 0 0 0 10 0 0 0 0 0 0 0 270 75 3 5 12 5 18 2 0 16 16 31 3 16 0 25 0 0 0 1 0 0 94 70 7 5 16 5 20 0 6 7 1 20 3 3 10 8 0 0 0 1 0 0 57 27 0 0 0 0 0 0 0 0 0 3 0 13 0 16 0 0 0 0 0 0 Partly Spent 43 1 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 Spent Abnormal 76 2 0 0 8 1 0 2 0 7 15 9 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 114 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Gonadal Condition Table 1. (cont'd.). July Gonadal Condition Maturity Species Mature Green Ripe 0 34 2 0 39 2 8 0 17 2 33 0 0 0 36 0 0 0 0 0 0 0 250 28 1 24 52 16 5 1 23 12 62 29 1 6 0 4 0 0 0 0 0 0 24 37 2 24 84 18 20 1 37 14 38 4 1 5 36 0 0 0 0 0 0 0 30 17 0 0 0 0 0 0 0 0 0 3 0 1 0 2 0 0 0 0 0 0 Partly Spent 38 3 0 0 0 0 0 0 0 0 5 12 0 0 0 1 0 0 0 0 0 0 Spent 158 5 0 0 7 0 0 0 3 0 52 10 0 0 0 1 0 0 0 0 0 0 Abnormal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 115 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Immature Table 1. (cont'd.). August Maturity Species Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Gonadal Condition Immature Mature Green 0 33 4 0 15 1 15 0 12 17 14 0 2 0 2 0 0 0 0 0 0 0 234 2 0 59 44 29 11 10 7 18 6 8 4 7 0 2 1 0 0 0 0 0 18 33 4 59 59 30 26 10 19 35 18 0 6 6 2 0 1 0 0 0 0 0 Ripe 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Partly Spent 15 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 0 0 0 0 0 0 Spent 101 2 0 0 0 0 0 0 0 0 2 7 0 1 0 0 0 0 0 0 0 0 Abnormal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Table 1 . (cont'd.). September Maturity Species Immature Mature Green 0 0 6 0 6 0 1 0 3 7 0 0 10 0 1 0 0 0 0 0 0 0 72 11 14 79 20 10 16 19 1 7 1 2 18 0 19 5 2 0 0 0 0 0 54 7 19 79 26 10 17 19 4 14 1 2 26 0 19 3 2 0 0 0 0 0 Ripe 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 2 0 0 0 0 0 0 Partly Spent Spent Abnormal 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 17 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Gonadal Condition Table 1. (cont’d.). October Maturity Species 0 0 1 0 0 0 0 0 0 2 0 0 8 0 0 0 0 0 0 0 0 0 Mature Green Ripe Partly Spent 39 2 1.3 131 9 3 6 16 4 6 0 7 30 0 1 1 1 0 0 0 0 0 39 2 14 96 9 3 6 16 4 8 0 7 36 0 1 1 1 0 0 0 0 0 0 0 0 35 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Spent Abnormal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 118 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Immature Gonadal Condition Table 1. (cont'd.). November Maturity Species 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Mature Green 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Ripe 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Partly Spent Spent Abnormal 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 119 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Pumpkinseed Largemouth bass Black crappie Immature Gonadal Condition Table 2. Monthly maturity and gonadal condition of each fish species captured in gill nets during 1977. April Maturity Species Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass Immature 0 0 2 0 0 0 5 0 1 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 Gonadal Condition Mature Green Ripe Partly Spent Spent Abnormal 11 0 118 2 30 3 20 19 27 4 0 0 1 5 0 1 0 0 3 0 0 0 0 0 10 0 30 2 20 3 25 1 13 3 0 0 3 3 0 0 0 0 2 0 0 0 0 0 1 0 74 0 3 0 0 18 6 1 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13 0 7 0 0 0 8 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Table 2. (cont'd.). Maturity Species 0 5 7 0 13 2 9 0 12 0 1 0 1 0 0 0 2 0 0 0 0 0 0 0 Mature 131 50 48 17 26 14 16 6 22 0 0 17 0 18 0 8 1 3 0 0 1 0 0 0 Green 108 58 13 17 24 8 25 2 18 0 1 15 1 5 0 4 3 0 0 0 1 0 0 0 Ripe Partly Spent Spent Abnormal 71 4 35 0 0 0 0 4 1 0 0 2 0 13 0 4 0 3 0 0 0 0 0 0 0 0 3 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 4 0 15 8 0 0 15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 121 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass Immature Gonadal Condition Table 2. (cont’d.). June Gonadal Condition Maturity Species 0 11 0 0 1A 3 2 0 6 0 0 0 0 0 15 0 0 0 0 0 0 0 0 0 Mature 306 31 3 17 33 16 13 1 A 3 A 11 1 19 0 13 0 0 0 1 0 0 0 0 Green Ripe Partly Spent Spent Abnormal 187 87 2 17 A1 17 15 1 10 3 A 7 1 5 15 7 0 0 0 1 0 0 0 0 100 5 1 0 0 1 0 0 0 0 0 3 0 1A 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 19 0 0 0 6 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 122 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowfin Longnose gar Channel catfish Bloater Smallmouth bass Immature Table 2. (cont'd.). July Maturity Species Partly Spent Immature Mature Green Ripe 1 24 0 0 36 274 85 0 20 22 95 70 0 20 58 46 35 0 0 0 22 2 0 0 0 112 2 0 0 0 0 0 0 0 0 0 19 0 6 0 0 0 13 0 0 0 0 0 0 0 0 0 0 1 17 36 5 0 7 0 5 0 0 0 1 0 1 1 0 0 20 17 9 2 0 1 13 1 0 0 0 1 0 1 1 0 0 0 0 1 0 0 6 0 3 0 0 0 0 0 0 0 0 0 0 0 32 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Spent Abnormal 12 3 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass Gonadal Condition Table 2. (cont'd.). August Maturity Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowfin Longnose gar Channel catfish Bloater Smallmouth bass Immature 0 38 6 0 9 9 3 0 1 35 3 0 2 0 1 0 0 0 0 0 0 0 0 0 Mature Green 214 18 6 25 9 33 7 0 8 L5 10 L9 2 4 0 8 1 0 0 0 0 0 0 1 13 42 12 25 17 42 10 0 9 50 11 1 4 4 1 1 1 0 0 0 0 0 0 1 Ripe 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 Partly Spent 49 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 Spent 150 13 0 0 1 0 0 0 0 0 2 11 0 0 0 0 0 0 0 0 0 0 0 0 Abnormal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 YZI Species Gonadal Condition Table 2. (cont'd.). September Maturity Species Immature Mature Green 0 29 2 0 17 2 2 0 3 0 3 0 3 0 0 0 1 0 0 0 0 0 0 0 100 4 32 68 22 41 19 68 0 10 7 11 7 2 16 4 3 0 0 0 0 0 0 0 93 32 34 68 39 43 21 68 3 10 10 5 10 2 16 2 4 0 0 0 0 0 0 0 Ripe 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 Partly Spent Spent Abnormal 2 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 5 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 125 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowfin Longnose gar Channel catfish Bloater Smallmouth bass Gonadal Condition Table 2. (cont'd.). October Maturity Species 0 5 6 0 4 2 0 0 0 2 3 0 6 0 0 0 1 0 0 0 0 0 0 0 Mature Green Ripe 13 3 38 234 8 5 13 8 35 114 12 7 0 0 9 9 0 0 4 0 4 0 2 18 0 6 0 1 0 0 0 0 0 0 0 4 0 6 3 2 15 0 5 0 2 0 0 0 0 0 0 0 0 0 0 0 0 9 0 1 0 0 0 0 0 0 0 0 0 Partly Spent Spent Abnormal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 126 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowfin Longnose gar Channel catfish Bloater Smallmouth bass Immature Gonadal Condition Table 2. (cont'd.). November Maturity Species 0 1 3 0 3 0 0 0 0 0 0 0 2 0 0 0 1 0 0 0 0 0 0 0 Mature Green Ripe Partly Spent Spent Abnormal 5 0 35 7 2 3 9 1 0 0 0 0 18 1 0 0 0 0 0 0 0 0 0 0 5 1 18 2 5 3 3 0 0 0 0 0 9 0 0 0 1 0 0 0 0 0 0 0 0 0 20 5 0 0 5 1 0 0 0 0 11 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 Spottail shiner Alewife Rainbow trout Lake trout White sucker Redhorse Brown trout Rainbow smelt Longnose sucker Gizzard shad Yellow perch Longnose dace Coho salmon Carp Chinook salmon Trout-perch Round whitefish Lake chub Northern pike Bowf in Longnose gar Channel catfish Bloater Smallmouth bass Immature Gonadal Condition APPENDIX B Table 1. Station Water condition parameters at stations 1 and 8 (control) and climatic parameters for the sample area on each sample date from April - November, 1976. 1 Water Temp. (C) Crnt, Dir. • Turb. 8 1 8 3.0 6.8 6.0 5.3 6.0 13.9 9.8 8.1 6.9 7.8 8.1 9.9 11.5 9.0 5.0 7.5 8.0 9.0 9.8 15.5 19.5 19.0 6.5 19.0 19.5 19.0 6.5 27.0 57.0 4.0 1.7 85.1 49.0 28.0 2.0 14.0 7.0 3.4 4.4 3.9 4.1 3.8 2.9 12.0 25.0 38.0 12.0 19.0 12.0 4.0 7.0 37.0 22.0 58.0 99.0 14.0 5.8 15.0 72.0 1 8 N S S N N S N N N N N S S N N N 0 S N N N S S N S S N S S N N S N N N N N S S N N N 0 S N N N S S N S S Wave Ht. 1 (cm) 8 Wind Dir. 24 Hr W Dir N SW N SW S S E E N NW N N SW SW N N W E N SW SE SW S SW SW SW SW SW SW S S E N N NW N N N S N N N E NE S S SW NW NE SE S N Baro. Pres. Date 04/01 04/06 04/07 04/09 04/13 04/19 04/21 04/24 04/28 04/29 05/06 05/11 05/12 05/14 05/19 05/24 05/26 05/31 06/02 06/09 06/12 06/20 06/21 06/22 06/23 06/28 07/01 3.0 6.4 6.1 7.0 7.9 13.9 0.2 9.2 7.8 6.0 7.1 8.9 10.2 9.0 5.0 4.0 7.0 9.0 10.0 15.0 19.5 18.7 17.0 17.0 19.5 19.0 7.0 — - 2.7 2.5 74.0 20.0 9.4 2.1 26.0 15.0 3.2 70.0 — 2.2 7.5 - 4.5 - 14.0 4.0 - 16.0 7 15 7 7 7 15 7 1 7 8 5 8 5 13 7 5 3 3 2 12 7 8 2 5 5 5 3 15 15 15 7 7 15 7 1 22 8 15 14 5 15 8 14 3 4 6 18 7 10 1 6 7 9 6 s N 29.60 29.79 30.09 30.28 29.94 30.02 29.48 29.86 29.70 30.20 30.23 29.94 29.98 29.85 29.95 30.02 30.08 29.80 30.16 29.96 29.84 30.04 30.00 30.02 30.08 29.80 30.00 Table 1. (cont’d.). Station 1 Water Temp. (C) Cmt Dir. Turb. 8 1 8 1 8 6.7 5.0 16.0 5.0 1.5 2.4 3.2 2.3 26.0 7.8 9.3 75.0 4.9 2.3 6.8 5.3 2.5 9.8 4.9 4.5 88.0 5.6 9.6 6.5 2.0 N N S N S N S S N N S N S N S S s s s s s s s s s s s s N N S S N N S S N S S N N S S N N S S N S S s - Wave Ht. 1 (cm) 8 Wind Dir. 24 Hr. W Dir. Baro. Pres. SW N N SW NE NW NW E NW NE N N SE SE SW SW N E S S E NE S E NE NW SW S NE SW NE NE SW E N NE NE NE S S NE SW NE NE N SE N NE SE N NE NW 29.96 29.98 29.89 29.79 30.06 30.01 29.93 29.78 30.20 30.10 29.90 30.08 30.18 30.20 30.15 30.13 30.24 30.02 30.78 29.90 29.88 30.22 30.08 30.38 30.17 29.92 Date 18.5 13.0 12.0 17.5 17.0 18.0 21.0 19.5 10.0 13.0 17.0 14.9 13.0 13.0 14.0 18.0 13.0 8.5 16.0 16.0 11.5 10.0 13.5 9.0 6.5 4.0 19.0 14.0 9.0 18.0 16.0 18.5 21.0 19.0 10.0 14.0 16.0 13.0 12.0 13.0 13.5 18.5 14.0 8.0 16.0 16.0 14.0 15.0 12.5 9.5 8.0 - 54.0 4.6 - 13.0 18.0 8.9 14.0 4.2 11.2 13.2 1.8 4.2 4.4 2.1 37.0 74.0 2.8 7.7 20.0 57.0 15.0 2.8 4.5 4.3 4.5 3.0 - 13 3 6 3 5 5 4 5 3 5 3 1 1 3 17 14 3 5 9 18 7 3 11 3 4 8 13 4 7 7 5 3 9 11 7 6 10 4 8 4 14 9 10 8 8 22 15 10 13 6 10 — 129 07/06 07/09 07/12 07/15 07/21 07/22 07/26 07/28 08/02 08/06 08/14 08/15 08/16 08/18 08/31 09/08 09/16 09/26 09/30 10/04 10/05 10/07 10/11 10/18 10/26 11/10 Table 2. Station Water condition parameters at stations 1 and 8 (control) and climatic parameters for the sample area on each sample date from April - November, 1977. 1 Water Temp. (C) Turb. 8 1 8 Crnt , Dir. 8 1 1 Wave Ht. (cm) 8 Wind Dir. 24 Hr. W Dir. Baro. Pres. Date 04/01 04/03 04/13 04/15 04/18 04/20 04/26 04/29 05/02 05/04 05/09 05/10 05/15 05/16 05/24 05/25 05/31 06/06 06/07 06/13 06/17 06/20 06/22 06/27 06/30 07/05 07/07 2.0 3.0 9.0 1.0 7.0 9.0 6.0 4.0 10.0 8.0 7.0 11.0 15.0 15.0 16.0 14.0 10.0 12.0 13.0 8.0 20.0 16.0 13.0 19.0 17.0 21.0 21.0 1.0 3.0 10.0 2.0 8.5 12.0 5.5 5.0 10.0 9.0 7.0 10.0 15.0 13.0 16.0 17.0 11.5 13.5 11.0 8.0 20.0 15.0 13.0 18.0 15.0 25.0 21.0 6.0 2.8 18.0 10.0 1.6 160.0 8.0 12.0 16.0 4.0 5.2 2.0 4.6 74.0 13.0 7.7 5.0 4.4 1.7 2.2 4.3 13.0 2.3 1.3 68.0 54.0 3.5 19.0 35.0 18.0 9.5 4.5 3.9 28.0 38.0 5.4 4.0 37.0 12.0 2.6 4.6 7.5 17.0 5.0 3.9 13.0 4.3 7.3 7.5 3.3 1.5 8.4 4.2 45.5 0 N S N S S N N S N S N N N N N N S N S N S S N N N S 0 N S N S S N N S N S N N N N N N S N S N S S N N N S 0 2 12 2 4 4 2 4 3 3 2 1 5 8 2 1 4 2 2 1 5 5 2 3 13 6 1 0 3 17 3 3 3 5 3 10 1 8 2 5 10 3 5 3 6 3 3 1 15 1 5 20 6 5 C NE N E C S W E N E S SW s s SW E E N S NW S NW N S S s E N N s E N s N N S N N N S S S N E N N N S S N S S s s 30.17 29.80 30.03 30.10 29.92 29.92 29.81 30.18 30.19 29.90 29.64 30.04 29.92 30.00 30.01 29.98 29.70 29.69 29.78 30.11 29.74 29.78 30.00 29.68 29.39 29.84 29.84 Table 2. (cont'd.). \ Station 1 Water Temp. (C) Crnt. Dir. Turb. 8 1 8 17.0 20.0 19.0 23.0 10.0 17.0 20.0 19.0 18.0 19.0 18.0 16.0 8.0 18.0 18.0 15.0 16.0 14.0 15.0 15.0 9.0 10.0 9.0 9.0 9.0 9.0 12.0 11.0 3.2 26.0 44.0 8.1 3.1 94.0 9.0 34.0 16.0 42.0 1.6 3.7 1.2 2.2 22.0 2.6 2.7 3.9 5.2 4.1 2.8 5.9 36.0 54.0 16.0 17.0 15.0 9.9 5.0 6.0 31.0 6.3 3.4 5.5 2.1 6.6 3.1 2.4 17.0 4.4 1.6 37.0 4.5 6.8 6.9 8.7 51.0 1.9 21.0 43.0 30.0 43.0 27.0 25.0 15.0 9.2 1 8 1 N N N 3 3 12 3 3 20 5 6 10 10 5 1 1 1 15 2 4 5 12 4 10 4 13 8 6 12 13 9 Wave Ht. (cm) 8 Wind Dir. 24 Hr. W Dir. 2 5 20 2 15 12 4 8 18 12 7 2 2 4 17 2 12 4 7 12 25 8 8 6 22 8 15 20 W SW SW N NW W S NW W S SW NE E SE N SE NE N E W N N W N NW S S SW W S S S N S S W SW w NW N N S s N E E E W N W W N N NW S S Baro. Pres. Date 17.0 20.0 20.0 24.0 12.0 18.0 19.0 19.0 18.0 17.0 18.0 16.0 8.0 17.0 19.0 16.0 15.0 14.0 14.0 15.0 8.0 10.0 9.0 9.0 9.0 9.0 12.0 11.0 N N S S N N N N N N S S s s s s N N S S S N N S N N N N S S N N N N N N S S S S s s N N S S s N N S N N N 30.05 29.93 29.88 30.07 30.17 29.64 29.82 29.86 29.78 29.80 30.00 29.90 30.18 20.16 30.02 30.02 29.82 30.04 29.92 29.78 30.23 29.96 30.02 30.04 29.96 30.11 29.96 30.00 131 07/13 07/17 07/18 07/21 07/26 07/31 08/07 08/10 08/13 08/16 08/18 08/23 08/25 08/29 09/06 09/08 09/13 09/22 09/23 09/27 10/03 10/05 10/13 10/17 10/19 10/20 10/25 10/26 Table 2 , (cont'd.). Station 1 Water Temp. (C) Crnt. Dir. Turb. 8 1 8 1 8 4.2 7.9 5.5 3.1 7.9 N N S N N N N S N N Wave Ht. 1 (cm) 8 Wind Dir. 24 Hr. W Dir. Baro. Pres. 12 12 5 2 2 NE NE N W S NE NE E S s 29.78 30.08 30.35 29.30 30.14 Date 11/01 11/02 11/07 11/08 11/30 12.0 12.0 10.0 11.0 3.0 12.0 12.0 10.0 11.0 3.0 52.0 47.0 8.0 3.0 30.0 10 10 2 3 3 132