Yellow perch, alewife, spottail shiner and round goby trawl catch per unit effort (CPUE) was evaluated in the Indiana waters of Lake Michigan from 1984-2006 to determine whether spatial or temporal variation in CPUE for these species occurred. Differences in CPUE among sites or periods were not clearly distinguished within a single sampling year. However, when compared over a 23 year time frame, spatial and temporal differences became evident. To determine the minimum number of samples needed to detect differences among sites and periods, we ran a Monte Carlo simulation using 23 years of empirical data. This compared favorably to results obtained from a power analysis that identified the minimum number of samples required to identify statistical differences. Sampling effort needed to distinguish differences in CPUE varied both spatially and temporally among the four species. Differences in sampling only became evident when multi-year efforts were employed. In addition, spatial and temporal differences in male and female (mature and immature) yellow perch proportions was also evaluated among our sample sites and periods from 1993-2006. / Department of Biology

Yellow perch, Perca flavescens (Mitchill), were collected for food habit determination from a transect in Indiana waters of Lake Michigan near Michigan City, Indiana between June and October in 1971 and June and September in 1972.The most important food items utilized on a mean annual basis were: unidentifiable organic material (UOM), alewife eggs, Pontoporeia affinis, fish (primarily alewife), insects (primarily chironomid larvae and pupae), and Eurycercus lamellatus. E. lamellatus, alewife eggs and UOM dominated 1971 stomach contents with P. affinis more important than E. lamellatus in 1972.Monthly stomach contents revealed heavy consumption of alewife eggs when available during the alewife spawning period, but these were replaced by P. affinis and fish (alewife) especially after July in both years.Differences between sexes of yellow perch captured by day and by night were minor and inconsistent.Differences between selected size groups (100-175, 176-225, 226-275 mm) manifested themselves in greater use of larger food items such as P. affinis and fish with larger length groups and as the summer progressed. The mean volumes of alewife eggs consumed, the most important food of yellow perch in this study, decreased significantly within each month both years as length of the yellow perch increased. In the large length groups, greater use of larger food items was made, but only fishes as a food item showed a signigicant difference between the two larger length groups.

The purpose of this research was to determine population trends of major nearshore fish species in Indiana waters of Lake Michigan from 1984 to 1998 to gain insight into species dynamics. Index trawl samples were collected twice monthly from June through August at three locations. Trends of catch-per-unit-effort (CPUE) were investigated for the most abundant species: yellow perch (Perca flavescens), alewife (Alosa pseudoharengus), spottail shiner (Notropis hudsonius), rainbow smelt (Osmerus mord iz), and bloater (Coregonus hoyi). Trawl catch of yellow perch, alewife, and spottail shiners at sites M, K, and G were strongly correlated suggesting similar fluctuations. Young-of-the-year trawl catch revealed that insight to population dynamics of species was not always reliable. Trawl CPUE of > age 1 fish provided insight to dynamics of the major species at all sample locations with strong trend similarities between sites. No strong major species interactions were found using simple linear correlations. / Department of Biology

Yellow perch, Perca flavescens, were collected by night trawling and gill netting at 5 m in a study area near Kintzele Ditch in Indiana waters of Lake Michigan during the months of June through September, 1975. Additional collections made by the Indiana Department of Natural Resources and the U.S. Fish and Wildlife Service using gill nets were included in some aspects of the study.Population characteristics were analyzed and compared to other studies. The rate of growth was significantly greater than in past Great Lakes' populations. The calculated length-weight relationships and growth rates were comparable to those reported by recent studies for southern Lake Michigan. Growth differed between males and females of the same age, and different ages were often represented in the same length interval. Nearly all male yellow perch were mature by age I and 130 mm. About half of the age II females and most at the 200 mm length interval were mature. Sex ratios were variable.Higher catch-per-unit-effort (cpe) was related to warmer water temperatures to the thermocline level. When water temperatures were mixed resulting in low inshore temperatures, cpe values were lower.There existed a great deal of sample variability within and between gear types as a result of seasonal population availability, gear characteristics, and non-random distribution of the population.Trawling, although more efficient than gill netting at sampling total numbers and widest range of lengths, was selective for smaller fish, and gill netting was selective for larger fish. Depth (from 5 m to 18.3 m) and particular gill net methods employed had little effect upon the sizes and length-percent frequency distribution sampled.Great differences between percentage age compositions compiled from trawl and gill net catches reflected the size selectivity of the gears. These results raised questions concerning the validity of management techniques involving percentage age composition and cpe index values to determine relative year class strength.The age groups I and II were represented by the proportion 8:2 (1:11) in the trawl catch which adequately sampled the sizes including the age I and II fish. Further study would be needed to determine the validity and usefulness to management considerations of this method of relative year class strength determinations. Recommendations for additional study were made.

The potential near-shore forage fish populations were investigated by bottom trawling during the months of June through August of 1984-86 in Lake Michigan, near Michigan City, Indiana. Data were collected on the six moat common species including: yellow perch (Perca flavescens); alewife (Aloes pseudoharenqus); rainbow smelt(Osmerus mordax); bloater (Coreaonus,hovi); spottail shiner (Notroois hudsonius); and trout-perch (Perconsis omiscomavcus). Results of the 1984-86 sampling period were compared with data for 1973 in an attempt to document changes in population density, species composition, annual catch, seasonal abundance, and population structure.The total trawl catch for all species increased nearly seven-fold since 1973 even though sample methods and collection effort were unchanged. A dramatic increase in yellow perch abundance was primarily responsible for the elevated levels sampled for all species from 1984-86.The species composition of the catch shifted since 1973. In 1973, spottail shiners were the most abundant species (41%) and trout-perch and alewives were the next most abundant species comprising 20% and 17% of the catch, respectively. Yellow perch, which comprised only 12% of the catch in 1973, increased to 81% of the catch in 1986. Bloater also showed a great increase in relative importance since 1973 when they were rare in the catch. Other species, including alewife, were relatively minor components of the total catch each year from 1984-86. The trawl catch results revealed that alewife and trout-perch declined 71% and 87%, respectively, comparing 1973 with 1984-86. During the same period, yellow perch increased 72-fold and bloater over 3000-fold. By comparison, the spottail shiner population was stable with no long-term changes, but rainbow smelt populations fluctuated widely.Seasonal abundance of adult fish (age I or older) generally decreased from June to August for each fish species and year sampled with the exception of yellow perch which peaked in July of 1973, and in August of 1985-86. Young-of-the-year fish were generally captured in late July and August.Population structure changes were evaluated by examining pooled length-frequency data. Yellow perch length-frequency distributions indicated that strong year classes were produced every year from 1983 to 1986. The 1985 year class was well over twice as large as any of the other years sampled. Spottail shiner and rainbow smelt length-frequency distributions remained approximately stable since 1973, while alewife length-frequency distributions fluctuated annually. Capture of bloaters was almost entirely limited to June, and consisted primarily of age I+ fish in 1984-86.These results reveal significant changes have occurred in the potential near-shore forage fish populations in Indiana waters of Lake Michigan since the early 1970's. Although several factors may be involved in the shifts noted, the major contributing factor is likely predator-prey interactions as a result of salmonid predator density.

Thesis (Ph. D.)--University of Michigan, 1940. / "Reprinted ... from the Journal of geology, vol. XLVIII, no. 5, July-August, 1940." Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 266-270.).

AbstractMacrobenthic population dynamics in the Indiana waters of Lake Michigan were examined from June to October, 1970. Species composition and density were compared within and between 5, 10, 15, and 18 m stations and transects at Michigan City, Burns Ditch, and Gary. The major groups of organisms sampled for all stations combined in Indiana waters, in order of abundance and percent composition, were: oligochaetes, the amphipod Pontoporeia affinis, sphaeriids, and chironomids. The Michigan City transect had the greatest abundance and percent composition of chironomids and sphaeriids. The Burns Ditch transect had the greatest abundance and percent composition of oligochaetes. The Gary transect had the greatest abundance and percent composition of P. affinis. A classification of the transects according to trophic values, derived from the proportion of indicator chironomids, revealed Michigan City and Burns Ditch transects as in the eutrophic range while the Gary transect was in the mesotrophic range.Ball State UniversityMuncie, IN 47306

Monthly whole-water phytoplankton samples were collected in Lake Michigan near Michigan City, Indiana from June, 1973 to May, 1974 on three transects at eight stations with depths ranging from 5 to 18m.A total of 226 taxa were identified in composite samples. The diatoms Fragilaria crotorensis (16;6), Thalassiosira fluviatilis (11%), and Tabellaria fenestrata (95%), numerically dominated the Lake Michigan phytoplankton assemblage during the study period.Principal components ordination revealed a well defined pattern of seasonal succession. No consistent differences between stations were found. Species diversity indices generally indicated a high level of community organization in spring and fall months and lowered estimates for summer and winter months.The phytoplankton community was dominated by diatoms throughout the year. Green and blue-green forms showed greatest abundance in the summer and. early fall with only minor occurrences during the remainder of the sample period.Species encountered in this study indicate continued succession of Lake Michigan phytoplankton and eutrophication of the southern near-shore water.Ball State UniversityMuncie, IN 47306

Yellow perch, Perca flavescens, were collected by trawling and gillnetting at 5m in a study area near Kintzele Ditch in Indiana waters of Lake Michigan. Sampling was conducted during the months of June, July and August in 1976 and 1977.Population characteristics were analyzed and compared to other studies. Growth rate and length-weight tended to be higher than in previous studies dealing with the Great Lakes, however, no specific reasons were identified. Growth differed between sexes, with females showing faster and more prolonged growth in older age fish. Significant overlap in ages I, II and III was apparent in both sexes, with growth differences evident between sexes of the same age. Virtually all (99%) age I male perch were mature, while only 15% age I females were mature. Approximately half of the age II females were mature with most age III females mature. Males were all mature at 150mm while females were all mature at 260mm.Sex ratios varied between samples, but were near unity for the combined sample period. No trends were apparent during the summer season for sex ratios in sex segregated populations.Catch-per-unit effort (CPE) remained relatively high during the entire sampling period. Lower CPE was noted with lower water temperatures. Sample variability was high throughout the sampling period, possibly due to gear selectivity, non-random distribution of individuals and repeated disturbances of the same area. When young-of-the-year were collected, their numbers were less variable than for older perch, a likely consequency of greater vulnerability to sample gear.The trawl tended to select for a wider range of sizes and greater total number of fish. The gill net consistently selected for larger fish. Neither method employed alone appeared capable of sampling the entire size range of fish.Differences in percent age in trawl and gill net samples were apparent with the gill net selecting for older fish. The trawl tended to sample a wide age range of fish.Comparison of data collected in Indiana and Michigan waters suggest fundamental differences in population structures. Indiana populations lacked significant numbers of larger, older fish which were adequately represented in samples from Michigan waters. Commercial harvest of perch in Indiana waters appears to be involved in the population structure differences.Ball State UniversityMuncie, IN 47306