We developed a mixed model to determine whether biotic (alewife, spottail shiner, round goby, yellow perch > age 1 and yellow perch < age 1 abundances) or abiotic (water temperature, water clarity) factors influenced growth rates in the Indiana waters of Lake Michigan during August from 1984 to 2007. This study suggests that young-of-the-year (YOY) yellow perch growth rates in southern Lake Michigan are influenced by temperature, spottail shiner abundance, and round goby abundance. We also collected age-0 yellow perch to identify details of early life history including timing of migration to pelagic waters, timing of return to nearshore waters, and spatial distribution following return to nearshore waters. This study suggests that yellow perch larvae hatch and are in the nearshore waters from June 1 to June 24, return date for demersal YOY yellow perch ranges from July 8 to August 16, with a mean return date of July 25, and spatial distribution of demersal age-0 yellow perch is relatively homogenous in Indiana nearshore waters. / Department of Biology

The relationship between yellow perch Perca flavescens abundance and growth rates were evaluated in the Indiana waters of Lake Michigan from 1984 to 2004. Relative abundance values were taken from trawl catch per unit effort (CPUE), while growth rates were determined by back-calculation. Abundance CPUE during the mid 1980's, was approximately one order of magnitude higher when compared to the 1990 to 2004 period. Growth rates were inversely related to relative abundance and were sexually dimorphic, with females growing faster than males. Regression analysis indicated approximately half of this observed variation in growth was due to abundance, and was most apparent with the smaller and younger fish. Both intraspecific competition and physiological changes associated with maturity are plausible explanations for the relationship. / Department of Biology

The Indiana waters of Lake Michigan were sampled weekly from May until August in 2009, 2011, and 2012 to determine the extent of yellow perch reproduction and the role Indiana waters play in yellow perch life history. Experimental gill nets were used to collect fish before, during, and after the spawning season from randomly selected sites along the Indiana shoreline. Yellow perch were then taken to an onshore processing station where they were weighed, measured, and visually examined to determine sex and maturity. Maturity stages of adult yellow perch were used to estimate the timing and duration of yellow perch spawning. Yellow perch population demographics were also compared to determine if different groups of yellow perch were present before and after the spawn. My data suggests that yellow perch spawning is strongly influenced by temperature and that Indiana waters are seasonally used by adult yellow perch for feeding. / Department of Biology

The yellow perch, (Perca flavescens), is an important commercial and sport fish in Indiana waters of Lake Michigan. The population is currently managed by temporary restrictions of commercial harvest. A computer simulation model was developed to examine the effects of various constant harvest quotas and alewife densities on yellow perch relative numbers.Model design is based on the SLAM II simulation language incorporating a FORTRAN biological subroutine. The age-structured population model includes measured or predicted biological characteristics of the dynamic pool model. Recruitment is based on a preestablished three-dimensional Ricker stock-recruitment function including alewife (Alosa pseudoharengus) species interaction as a constant or stochastic factor. Sex-specific natural mortality rates were established through life history parameter analysis and the von Bertalanffy growth factors. Density-dependent growth is incorporated into each year of a model run and fluctuates with the simultaneous density of fish. Constant levels of commercial harvest ranging from 0 to 700,000 kg were used in 20-year forecasts. Initial conditions for model runs were 1984 and 1994 trawl CPUE levels when yellow perch were at high and low levels, respectively according to standardized sampling. Response variables were examined as mean catches over each forecast length and included: age 2 fish, spawning stock (z 190 mm), and total catch > age 1.Alewife densities had a tremendous impact on mean catches of the response variables. Highest catches under any forecast period occurred when alewife was considered absent from the system. Catches declined as alewife density was increased as a 20-year constant under each harvest regimen.Catches of spawning size fish were maintained at highest levels for all forecast periods when harvest was set to zero. Catches of young fish were moderate with this harvest regimen if initial catch conditions were high such as in 1984. Catches of young fish were always higher in the absence of a commercial fishery if initial catch conditions were low such as in 1994. Low to moderate harvest quotas could maintain moderate levels of young fish for the forecast length if initial model conditions were high. However, these quota levels for the 1984-2004 forecast length resulted in lower mean catches of spawning size fish as compared to the no commercial fishery regimen. The best case scenario for all response variables when initial catch conditions were low was under a no commercial harvest regimen. / Department of Biology

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Biology

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

A computer simulation model was developed to examine the effects of various levels of alewife densities, harvest, and bycatch rates on yellow perch Perca flavescens relative densities in Indiana waters of Lake Michigan. The model utilized STELLA® Research software to develop the age-structured population model to include measured or predicted biological characteristics of density-dependent growth, recruitment, and mortality.The model was validated by simulating historically documented yellow perch catch per unit effort (CPUE) from 1984 - 1998. A strong linear relationship (R2= 0.70) between the model predicted CPUE values and the actual CPUE values was found. Twenty year model projections were performed using 1998 yellow perch trawl CPUE as starting values. Alewife abundance was established as either constantly high, constantly low, or allowed to fluctuate randomly and forecasts made used the average of 100 runs. Harvest was imposed on the yellow perch population at 20, 40, and 60% rate levels for fish >_ 200 mm coupled with bycatch at20, 40 and 60% rate levels for fish ranging from 165 - 200 mm.Alewife abundance was the major factor determining the relative abundance of the yellow perch population. On average, constantly high alewife abundance with no harvest or bycatch resulted in projected continuing suppression of yellow perch abundance from 1998 levels. The model predicted the population to rebound using constant low and random alewife abundance with no harvest or bycatch to approximately 1,100 fish/h and 700 fish/h, respectively.The model revealed harvest to have a generally negative impact on the yellow perch population. Increasing harvest and bycatch rate levels resulted in the suppression of projected increases in yellow perch relative abundance. Additionally, increasing harvest and bycatch rates resulted in greater predicted declines in yellow perch abundance. / Department of Biology