Midwest Fish & Wildlife Conference 2019

AUTHORS: Richard T. Kraus, US Geological Survey - Lake Erie Biological Station; Michael J. Hansen, US Geological Survey - Hammond Bay Biological Station; Matthew D. Faust, Ohio Department of Natural Resources - Division of Wildlife; Graham D. Raby, University of Windsor; Christopher S. Vandergoot, US Geological Survey - Lake Erie Biological Station; Charles C. Krueger, Michigan State University

ABSTRACT: Migratory fish movement can be classified as partial or differential migration, contingent behaviors, or other types of alternative migratory tactics. Growing evidence suggests that multiple variables, including metabolic and growth trajectories, risk-reward tradeoffs, personality, social interactions, and current physiological state underpin such modalities. We combined acoustic telemetry with sclerochronology to investigate if and how growth was associated with seasonal habitat use of a migratory freshwater fish, Lake Erie Walleye Sander vitreum. Non-linear mixed-effects modeling of back-calculated length-at-age from fin spines revealed individual growth trajectories that varied among spawning locations. Further, logistic principal components analysis of acoustic telemetry detections revealed stock-specific patterns in seasonal habitat use. Our results highlighted that individuals and groups of individuals within a stock are likely subjected to varying levels of fishing mortality based upon their migration pattern. For managers, differences in growth associated with spatial modalities in movement may translate into overexploitation of population segments.