Lake Sturgeon on the Move? Identification of Lake Sturgeon Migrants into a Genetically Deficient Area

Lake sturgeon, Acipenser fulvescens, are listed as threatened or endangered throughout most of its range due to historic overfishing and modification of critical spawning habitat. Dams have been noted as an additional factor limiting lake sturgeon population persistence as movements into heterogeneous habitats are critical during various life stages. While elimination of migration barriers, specifically dams, is viewed as a potential strategy to ecologically and genetically rehabilitate remnant populations, understanding movements of lake sturgeon into habitats above a previously impassable, but currently breached dam, is important for future management plans. Two populations of genetic distinction, the Grasse River (n=90) and the St. Lawrence River (n=82), were analyzed using twelve microsatellite loci to identify migrants into the Grasse River, where a low-head dam historically prevented upstream migration from the St. Lawrence River.  Using two approaches to assign individuals to their source population, we identified a single potential migrant into the Grasse River from the St. Lawrence River after the low-head dam was breached, therefore indicating potential re-colonization movements into a genetically deficient region. Further simulation analysis will reveal the estimated number of migrants needed to increase the genetic diversity in the Grasse River lake sturgeon population.