Diet, Age, and Reproduction of Trout-Perch in the Western Basin of Lake Erie

Trout-perch Percopsis omiscomaycus is an abundant, yet poorly understood, benthic fish found in Lake Erie.  Since the last study conducted on trout-perch in the 1950s, Lake Erie has undergone major ecological changes.  We evaluated the notion that trout-perch have responded to these ecological changes through changes in diet, age, and reproduction.   Trout-perch were collected at 50 sites across the western basin of Lake Erie using a bottom trawl.  We compared proportions of prey items in trout-perch stomachs to their occurrence in benthic samples collected at a subset of the trawl sites.  Preliminary diet analyses indicate chironomid larvae and Hexagenia sp. nymphs are the most frequently consumed prey whereas chironomid larvae and gastropods account for the majority of benthic invertebrates available.  Historical data revealed that 25% of trout-perch diets included gammarus, and 6% included fish.  However, in this study, gammarus is rarely found and no fish remains have been discovered among examined stomach contents.   Fecundity analysis suggests that the trout-perch may have group-synchronous development of oocytes with indeterminate fecundity.  Further analyses of age class structure, growth rate, and diet are currently underway.