Developing an integrated ecosystem assessment of Lake Erie fisheries

Session: Ecosystem-Based Management: Challenges and Opportunities on the Great Lakes Coasts

Michael Fraker, The Ohio State University, [email protected]
Kenneth Frank, Bedford Institute of Oceanography, [email protected]
James Hood, Aquatic Ecology Lab, The Ohio State University, [email protected]
Stuart Ludsin, The Ohio State University, [email protected]

Abstract

Quantifying patterns and trends among multiple stressors and ecosystem components is a necessary first step toward implementing ecosystem-based fisheries management in any ecosystem. We conducted preliminary analyses of >100 long-term datasets comprising annual anomalies of physical, chemical, and biological components of the Lake Erie ecosystem. Ordination of the dataset, conducted at the whole-lake scale, indicates significant shifts in ecosystem state through time. Our initial results identify three different “regimes” characterized, in the most general terms, by: 1) a relatively wet period during 1950-1960 with high walleye and low yellow perch harvests; 2) a somewhat drier, colder period during 1960-1985 with high total nutrient inputs, low walleye harvests, and high yellow perch harvests; and 3) a wet, warmer period during 1985-2010 with relatively lower nutrient inputs, higher walleye harvests, lower yellow perch harvests, and a shift from a pelagic to benthic fish assemblage. Furthermore, these analyses showed synchrony among a suite of physiochemical, biological, and fisheries variables. Beyond presenting these results, we discuss our plans to identify indicators of ecosystem state change in Lake Erie and test hypotheses concerning how ecosystem shifts have driven the dynamics of fish communities.