Long Term Migration Patterns of Adult Lake Sturgeon, Winnebago System, Wisconsin

Understanding the migration patterns of adult lake sturgeon (Acipenser fulvescens) is important for long term rehabilitation of lake sturgeon stocks which once were wide ranging and abundant throughout the Great Lakes.  During 2004 to 2009, 177 wild adult pre-spawn and spawning lake sturgeon in the Winnebago System, Wisconsin, were captured between November and April at pre-spawn staging and spawning areas and surgically implanted with long term sonic transmitters.  Fish were tracked by a grid of 34 permanent receiving stations strategically located throughout the system.  Pre-spawn adults migrate out of Lake Winnebago to winter staging areas in the Upriver Lakes and rivers between September and March, and initiate final migration to specific spawning sites when spring river temperatures reach 8-10° C.  After spawning, females immediately begin their descent back to the Winnebago Pool Lakes returning up to 200 km in an average of 5 days.  Males will remain at one or more spawning sites until all females have spawned before they begin their descent averaging 11 days back to the lakes.  The majority of tagged males made annual spawning runs. Females spawned on 3, 4 and 5 year cycles in close to equal proportions and displayed modest site fidelity.