Stock Structure of Bowhead Whales Inferred from mtDNA and SNP Data
Amy B. Baird, Geof H. Givens, John C. George, Robert S. Suydam, and John W. Bickham
International Whaling Commission
This report analyzes mtDNA sequence data and SNP genotypes to examine stock structure in bowhead whales, Balaena mysticetus. The focus of the study is the Bering-Chukchi-Beaufort Seas (BCB) stock, with fewer samples from the Eastern Canadian Arctic (CAN) and Sea of Okhotsk (OK) used for comparison. mtDNA data includes sequences from the HVR1 portion of the control region, cytochrome-b, and ND1 totaling 2494 bp. The SNP panel, described in Baird et al. (2017), contains 69 autosomal loci (analyzed here) and 7 sex chromosome markers (to be used in future studies). Population genetic analyses indicate that the BCB and CAN populations are not highly differentiated, but that the OK population is easily distinguishable from both BCB and CAN. There is no evidence of significant sub-structuring of the BCB stock when comparisons are made among geographic and seasonal strata. These results are consistent with previous studies of mtDNA control region sequences, focal microsatellites, and a smaller SNP panel, as well as satellite telemetry data.