This project will investigate the food web effects of removing a widely introduced non-native predator found in northern lakes. Smallmouth bass were introduced into the study lake more than 50 years ago, which resulted in reduced abundance of native prey fish and major food web changes. A smallmouth bass removal program implemented in 2000 resulted in increased native prey fish abundance, restoration of food web linkages (measured using stable isotopes in fish tissue), and changes in mercury concentrations in top predators. Project goals are to: 1) quantify changes in lake fish communities, food web linkages and mercury bioaccumulation that have occurred in response to the ongoing removal effort, 2) evaluate the processes responsible for these changes, 3) and evaluate predator removal/control as a tool to manage lake ecosystems.
Limited information is available regarding the effects of large-scale predator manipulations, which are commonly implemented to provide recreational angling opportunities in North American lakes. Results from this study will provide an improved ability to: 1) use stable isotopes in fish tissue as a metric for lake restoration, 2) understand and alter processes responsible for mercury accumulation in sport fish, and 3) implement management approaches to restore native fish communities impacted by dominant non-native species.
