Evaluating short-term survival of walleye implanted with acoustic transmitters at elevated temperatures in Lake Erie

WBWAE

July 2015 - June 2016

Walleye is an economically and ecologically important native fish species in Lake Erie. Walleye in Lake Erie show complex life histories together with spatial and temporal variation among stocks. Results from previous tagging studies suggest western basin spawning stocks either remain in the western basin year-round or emigrate (i.e., toward the central and eastern basins of Lake Erie or Lake Huron via the Detroit and St. Clair rivers) after spawning occurs. Most of these walleye immigrate back toward the western basin during autumn and overwinter near the spawning grounds. As a result of this migratory behavior, Lake Erie walleye stocks from the different locations can become intermixed as they disperse from their spawning grounds. Exploitation of mixed-stock fisheries is commonly recognized in freshwater and marine fisheries. Further, stock-based assessments are typically done on spatial management units that have been established for a stock believed to be associated with a single, as opposed to multiple, spawning populations. Such assessment information when presumed to be from a single stock can lead to unintended overexploitation of local stocks and inappropriate management advice. Accurately quantifying mixing (i.e., movement) rates among stocks and the ability to identify source population(s) of harvested fish in different areas remains a difficult, yet important, issue for managing mixed-stock fisheries. Acoustic telemetry provides a means for estimating stock-specific movement and a novel approach for estimating the contribution of individual stocks to the fishery and/or population. A key uncertainty surrounding the feasibility of such a study is the ability to minimize mortality from the tagging process for walleye caught during summer months. Thus, prior to using this novel approach of tagging when stocks are mixed, we want to assess whether post-surgery survival rates are conducive for achieving study objectives (e.g., stock contribution, movement rates, and annual survival rates)

• Determine immediate (< 24 hours), short-term (2–30 days), and long-term (> 30 days) survival rates of angler-caught walleye implanted with acoustic transmitters during late spring and early summer when water temperature are elevated (i.e., >20° C).

• Matthew Faust (Ohio Department of Natural Resources) - matthew.faust@dnr.state.oh.us
• Chris Vandergoot (Michigan State University)
• Richard Kraus (United States Geological Survey)

• Ohio Department of Natural Resources
• United States Geological Survey

• Great Lakes Fishery Commission