Multi-decadal trophic shifts in Lake Erie Yellow Perch Perca flavescens

In Lake Erie, yellow perch Perca flavescens support vast commercial and recreational fisheries, yet populations have recently declined. Using N=5,889 yellow perch stomachs collected from 1997 to 2021, we explore trends in the feeding ecology and trophic level of yellow perch with generalized additive models (GAMs). Models revealed a significant decrease in yellow perch trophic level (-0.15 trophic levels in the last decade), and significant dietary shifts. Yellow perch have shifted away from feeding on piscine prey and round goby Neogobius melanostomus over the 25-year time series, and now feed on invertebrates more frequently – including invasive waterfleas (Bythotrephes longimanus and Cercopagis pengoi) and Chironomids. Dietary patterns appear to reflect broad ecological changes – invasive waterfleas have proliferated while populations of forage fish and round goby have declined. Furthermore, hypoxia events have increased in duration and severity, which may explain observed increases in Chironomid consumption, which are hypoxia tolerant. This study demonstrates trophic adaptability in yellow perch, which have changed feeding behavior and trophic position in response to novel invaders and changing environmental conditions.