A Model System for Studying the Effects of Invasive Predatory Cladocerans (IPC) on Zooplankton Behavior

Abstract

The Great Lakes have experienced a new wave of species invasions dominated by exotic invertebrates. Two of these species include the invasive predatory cladocerans (IPC) Bythotrephes cederstroemi and Cercopagis pengoi . Currently, they are suspected to be disrupting the Great Lake food webs at the lower trophic levels with possible effects permeating bottom-up into the higher trophic levels that directly influence fish recruitment. One way these invasive predators may be causing significant changes in the Great lakes could be through their effects on the diel vertical migration (DVM) behavior patterns of zooplankton prey. This research plans to focus specifically on the current effects of the non-native spiny water fleas, B. cederstroemi and C. pengoi . Predator-derived infochemicals from these species may be inducing temporal and spatial changes in zooplankton prey DVM behavior patterns such that these prey are less available to other predators. Native species that rely heavily on zooplankton as prey include yellow perch, alewife, and many young-of-year and larval fish. These fish, in turn, serve as important food for both salmon and lake trout. Recent declines in fish recruitment are pressuring us to learn more about the effects of potentially harmful IPC.