9407859 Stein This project examines the trophic cascade hypothesis in lower-latitude US reservoirs, where the dominant paradigm of top-down or bottom-up trophic controls may not hold. Specifically, gizzard shad appear to neither be controlled by fish predators nor by their zooplankton prey. The investigators hypothesize that the shad themselves regulate community composition. This research will test this idea by examining larval shad-bluegill interactions in eight reservoirs in Ohio and Alabama. The investigators will also conduct experiments on zooplankton and larval shad productivity, and develop models of these trophic interactions. This research will extend the current understanding of ecosystem control and community structure, yielding a more general understanding of the dynamics of food webs. The results of this research have applications in the management of fish stocks, reservoir management, and conservation biology.