Individual-based model simulations of a zebra mussel (Dreissena polymorpha) induced energy shunt on walleye (Stizostedion vitreum) and yellow perch (Perca flavescens) populations in Oneida Lake, New York

Zebra mussels (Dreissena polymorpha) recently invaded North American aquati c ecosystems and are hypothesized to impact lakes by increasing water clari ty through filtration and shunting energy from pelagic to benthic pathways (ES effect). We used an individual-based model of Oneida Lake, New York, wa lleye (Stizostedion vitreum) and yellow perch (Perca flavescens) population s to simulate ES effects on percids by lowering zooplankton density and pro duction rates and increasing benthos rates. We performed 50-year simulation s involving both zooplankton and benthos changes together and each change a lone. We also performed simulations to determine robustness of model predic tions under different assumed levels of zooplankton and benthos, increased forage fish and mayflies, and walleye stocking. Predicted ES effects were e limination of walleye high-recruitment years, resulting in a 30% reduction in adult walleye abundance. Yellow perch adult abundance increased by 6% du e to reduced walleye predation. Neither component (zooplankton or benthos) of ES generated the same total response for yellow perch as both components together. Simulated walleye stocking and increased forage fish density had little effect on model predictions. Increased mayfly densities offset pred icted ES effects by buffering predation on juvenile percids. Model predicti ons of ES impacts on percids generally were consistent with observed change s in Oneida Lake since zebra mussel arrived.