Changes in the Benthic Community of a Small Precambrian Lake following the Introduction of Yellow Perch, <i>Perca flavescens</i>

Abstract

The introduction and proliferation of yellow perch, Perca flavescens, in Little Minnow Lake, Algonquin Park, Ontario, resulted in changes in biomass and size structure of the benthic community. Biomass, mean organism weight, and density data are presented for nine groups of benthic macroinvertebrates for two years before and one year after perch introduction. An approximately 60% reduction in total benthic biomass and an approximately 50% reduction in mean weights occurred in the littoral zone after perch introduction. Vertically migrating profundal benthos showed an approximately 30–60% reduction in mean organism weight but no significant change in biomass. We conclude that fish predation can significantly alter species composition, skew size structure towards smaller invertebrates, and reduce total benthic biomass.