Genetic population structure of gray whales (Eschrichtius robustus) that summer in Clayoquot Sound, British Columbia

To determine the sex composition of gray whales that summer in Clayoquot Sound (CS), British Columbia and to assess whether these animals represent a genetically distinct subgroup of the eastern North Pacific (ENP) population, I collected skin samples from 18 individuals in CS ("residents"). Fourteen samples obtained from other areas served as random representatives of the overall population in the ENP ("non-residents"). Sex was determined for each sample; the nucleotide sequence of a 311 base-pair segment at the 5$\sp\prime$ end of the mtDNA control region was determined by automated sequencing. The sex ratio among residents was 2.6 to 1 nominally biased towards males, but was not significantly different from parity (p = 0.06). Residents were not significantly different from non-residents (Kst = $-$0.02, p = 0.79). Neighbor-joining analysis revealed three clades that did not correspond to any obvious geographic pattern. These data indicate the ENP population is genetically homogeneous.