Food habits of the yellow perch in Indiana waters of Lake Michigan near Michigan City, Indiana, in 1971-72

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.Thesis (M.S.