Impact on Daphnia pulex of Predation by Young Yellow Perch in Oneida Lake, New York

Abstract

Abstract The response of a Daphnia pulex population to fluctuations in abundance of young (age-0) yellow perch Perca flavescens was examined in Oneida Lake, New York, 1975–1979. Comparison of yellow perch biomass and Daphnia pulex abundance suggested daphnid populations could tolerate predation by 10 kg of young fish˙hectare-1 but reproduction could not compensate for predation when biomass of young exceeded 20–40 kg˙hectare-1. Consumption by young yellow perch exceeded Daphnia pulex production in 1975 and 1977, when daphnids disappeared, but maximum daily consumption was less than 27% of production in 1976 when daphnids were abundant through late summer. Since 1968, D. pulex populations have persisted through late summer in years when young yellow perch were scarce and disappeared when young were abundant. The decisive role of young yellow perch in the regulation of Daphnia pulex abundance is of importance to the broader fish community in Oneida Lake.