Molecular Genetic Stock Discrimination of Belugas (<i>Delphinapterus leucas</i>) Hunted in Eastern Hudson Bay, Northern Quebec, Hudson Strait, and Sanikiluaq (Belcher Islands), Canada, and Comparisons to Adjacent Populations

Abstract

Belugas (Delphinapterus leucas) harvested from communities on the eastern Hudson Bay (EHB) arc, Sanikiluaq on the Belcher Islands, northwestern Quebec, Hudson Strait, neighboring areas of Hudson Bay, and the St. Lawrence were characterized by differences in the mitochondrial DNA (mtDNA) d-loop sequence and in 15 nuclear microsatellite loci. Results supported the hypothesis that communities outside the EHB arc hunt some EHB belugas, which were strongly differentiated from all neighboring sample populations by mtDNA haplotypes and weakly differentiated by microsatellite data. Belugas genetically most similar to those sampled in EHB comprised 19% of the harvest in Hudson Strait and Ungava, 15% in northwestern Quebec, 9% in western and northern Hudson Bay, 8% in Sanikiluaq, and 5% in Kimmirut (though many were possibly not belugas from EHB, but uncommon genotypes in other stocks). Within EHB, belugas from the Nastapoka River (1984-95) and elsewhere on the EHB arc (1993-97) were very similar. Using simple probabilistic calculations to assign individuals to their most likely sample population, we estimated that 15% of belugas hunted in EHB could be from northern or western Hudson Bay and 3% from Sanikiluaq. St. Lawrence River belugas were strongly differentiated from all other sample populations by both haplotypes and microsatellites. Stocks in Arctic populations were identified by different proportions of alleles and by genetic consistency over several years. Belugas from Sanikiluaq, Kimmirut, and EHB may represent three separate stocks, while large genetic diversities in northern Quebec, northern Hudson Bay, and Arviat confirm that mixtures of stocks were harvested in these areas.