Yellow perch Perca flavescens spawning was evaluated in southern Lake Michigan during 2009 to determine the timing, location, and extent of spawning activity. Maturity state (i.e., pre-spawn/post-spawn), gonadosomatic index (GSI), mean length, length frequency distributions, and sex group proportions were also evaluated. No egg skeins were discovered during the study. The GSI decreased during the duration of the spawn. Spent females were larger than pre-spawn females. Following the spawning season another assessment was conducted to determine whether differences existed in the spawning and post-spawning population demographics. Abundance, length frequency distributions, proportions, and relative stock density were evaluated. Abundance of fish in the post-spawning period increased six-fold and paralleled a shift in length frequency distribution to larger median size. An increase in the proportion of females and relative stock density from the spawning period to post-spawning period was discovered. These data infer adult fish were spawning elsewhere, and then migrating to Indiana. / 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