Great Lakes-wide Disturbance Assessment: Lake Erie

Session: Imperiled Species in the Great Lakes Basin: Identifying Threats and Restoring Populations (2)

James McKenna, Tunison Lab. of Aquatic Sciences, U.S. Geological Survey, [email protected]
Catherine Riseng, University of Michigan, SEAS, [email protected]
Kevin Wehrly, Michigan Dept. Natural Resources, Inst. for Fisheries Res., [email protected]

Abstract

Disturbances to aquatics habitat are not uniformly distributed within the Great Lakes, some disturbances are widespread and others are localized. Acute effects can be strongest in nearshore areas and Lake Erie may be the most strongly affected among the Great Lakes. Furthermore, different fish species may respond to disturbances in different ways. A means to identify and evaluate locations and extent of disturbances that affect fish is needed throughout the Great Lakes. We used partial Canonical Correspondence Analysis (CCA) to separate “natural” effects on nearshore Lake Erie fish assemblages from disturbance effects. Species–specific models of fish abundance as a function of disturbance (CCA axes functions) were developed and lakewide predictions mapped.  Yellow Perch abundances showed little effect of disturbance in extensive areas of the western basin and north shore, but low perch abundance was associated with numerous areas of the eastern and western basin and along the south shore.  In contrast, Alewife abundance responses detected greater disturbance offshore than in shallow areas. Response models for other species are being developed. This approach may be used to assess conditions throughout the Great Lakes, assisting with identification of priorities for restorations and/or protection. Future work will expand to all Great Lakes.