The effect of multi-year vs single-year stocking on lake sturgeon (Acipenser fulvescens Rafinesque, 1817) genetic diversity

Abstract

Summary Many lake sturgeon (Acipenser fulvescens Rafinesque, 1817) populations in the Great Lakes have not recovered from previous threats, whereby stocking can increase population abundances. Stocking in Oneida Lake, New York used two approaches: single-year stocking using sturgeon from the Des Prairies River and multi-year stocking using sturgeon from the St. Lawrence River. Stocked A. fulvescens were sampled and assigned to their corresponding stocking strategy based on age. Samples were analyzed at 12 microsatellite loci to evaluate how a single year of stocking (N = 273) and multiple years of stocking (N = 100) affected genetic diversity and effective population size (Ne). Single-year stocking resulted in lower genetic diversity, likely due to a small number of parents. Multi-year stocking retained most of the genetic diversity of the source population, compensating for the few parents available in a single year. Although multi-year stocking resulted in a higher Ne, the Ne:N ratio was lower (0.34) compared to single-year stocking (0.65), likely due to unequal sex ratios and family size variance across years. It is recommended that stocking of Lake Sturgeon take place over several years. However, consistent numbers need to be stocked each year and family size should be equalized across cohorts in order to maximize Ne.