Rethinking Sturgeon Migration: Dispersal Patterns of Lake Sturgeon in the Lake Huron-to-Lake Erie Corridor

This presentation summarizes recent results for an ongoing project focused on helping fishery managers quantify the spatial extent, population structure, and abundance of the lake sturgeon (Acipenser fulvescens) that spawn in the Detroit-St. Clair river system (DSCRS).  A key question is whether DSCRS lake sturgeon represent a single population or several semi-isolated demes functioning as a metapopulation.  To address this question, lake sturgeon were captured, implanted with acoustic transmitters with a 10-year battery life, and then released back into the environment.  Since spring 2012, movements of tagged individual have been tracked on strategically located lines of acoustic receivers.  Analysis of tracking data showed that SCRS lake sturgeon have complex migration patterns with some individuals migrating as far 150 km during the period of observation.  Movement data to date suggest that DSCRS lake sturgeon function as multiple partially-isolated spawning groups rather than a single population.  Surprises revealed by year-round tracking of sturgeon movements included the high prevalence of partial migration, upstream movements to feeding/overwintering grounds, and near complete lack of use of Lake Erie.  Fish tracking data also led to the discovery of important sturgeon overwintering habitats in Lake St. Clair.