Do Life History Traits of Lake Erie Yellow Perch (Perca flavescens) Show Plastic Responses to the Demographic Effects of Harvesting?

Harvesting can impose potentially negative effects on natural populations, including reduced abundances and evolutionary changes in production traits, such as age and size at maturity. Individual fish can display plastic life history responses to local resource conditions, but the effect of harvesting on plastic life history responses has received little attention in commercial and recreational fisheries. We tested a simple population model that incorporates the effects of harvesting on YOY abundance, intraspecific competition, individual growth, and plastic responses in age- and size-at maturation using time series data for Lake Erie Yellow Perch collected from 1991 to 2008.  Rapid changes in maturation age were strongly consistent with plasticity in individual life history, but the time lags of responses did not match the three-year response time predicted by our harvest-mediated model of plasticity. Unexpectedly, plastic life history responses were related to harvest and adult density at double the predicted generation-time.  We hypothesize that changes in life history traits in these Yellow Perch may be plastic responses to environmental factors unrelated to harvest, to harvest effects on other aspects of the Lake Erie food web that influence perch life history decisions, or to harvest effects on grand-offspring mediated through maternal effects.