Genetic analyses of dispersal, harvest mortality, and recruitment for remnant populations of lake sturgeon, Acipenser fulvescens, in open-water and riverine habitats of Lake Michigan

Lake sturgeon, Acipenser fulvescens, have been severely impacted by anthropogenic disturbance and are a conservation priority throughout their range. Restoration efforts are impeded by a lack of information regarding patterns of recruitment and habitat use during non-spawning periods. Using the significant spatial genetic structuring of remnant populations of lake sturgeon throughout the Lake Michigan basin, combined with mixed-stock analyses and individual assignment, I examined (1) population-specific occupancy of open-water habitats and (2) the population composition of a sport fishery on the Menominee River. Also, by combining estimates of population of origin with estimates of age, along with the uncertainty in each of these estimates, I estimated recruitment within lake sturgeon populations since 1975. I found evidence for non-random habitat occupancy in northeast and western portions of Lake Michigan, suggesting that natal river and forage availability may affect habitat occupancy. Significant heterogeneity in habitat occupancy was also observed throughout Green Bay. Mixture analysis of a year of harvest from the downriver section of the Menominee River suggests that 17% of individuals harvested were not of Menominee River origin. A retrospective analysis of recruitment provided evidence for similar patterns in recruitment across Lake Michigan populations, despite varying historical population size.