30-5 Ecosystem level assessments of hypoxia impacts on the food web and fisheries of Lake Erie

Wednesday, September 15, 2010: 9:40 AM
303 (Convention Center)
Hongyan Zhang, PhD , Snre-Ciler, University of Michigan, Ann Arbor, MI
Edward S. Rutherford, PhD , NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI
Doran Mason, PhD , NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI
Timothy, B. Johnson, PhD , Ontario Ministry of Natural Resources, Picton, ON, Canada
Aaron T. Adamack, PhD , Snre-Ciler, University of Michigan, Ann Arbor, MI
Xinhua Zhu, PhD , Biological Sciences, University of Windsor, Windsor, ON, Canada
Don Scavia, PhD , Snre, University of Michigan, Ann Arbor, MI
Hypoxia resulting from anthropogenic eutrophication has long been a problem for Lake Erie. Studies of the sublethal impacts of hypoxia on fishes have focused on individual species consumption, behavior and spatial distributions over short time periods, but the long-term effects on the fish community and its food web are poorly known. We used an ecosystem-based model, Ecopath with Ecosim, to investigate the ecosystem-level impacts of hypoxia on the food web and fisheries in the central basin of Lake Erie, and to explore different scenarios of water quality management. Our model includes 15 fish species, 6 benthic groups, 6 zooplankton groups, 4 algal groups, and 3 detritus groups. We balanced our Ecopath model with data collected in 2005 and calibrated the Ecosim model using data from 1994 to 2005. Our model simulated the population dynamics of many fish species in the ecosystem, e.g., rainbow smelt, gobies, yellow perch, etc, and model simulations indicated that hypoxia decreased yellow perch biomass compared to normoxic conditions. We present quantitative estimates of hypoxia impacts on population dynamics of fish species in Lake Erie and discuss how different water quality management strategies may affect food web structure and function, and fisheries in Lake Erie.
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