Preliminary analysis of mitochondrial DNA variation in a southern feeding group of eastern North Pacific gray whales

Although the majority of eastern North Pacific (ENP) gray whales migrate to feeding grounds in the Bering and Chukchi Seas, some terminate the migration in more southerly areas such as British Columbia (BC). Long-term sighting studies in Clayoquot Sound (CS), BC, indicate that approximately 35-50 individuals exhibit long-term fidelity to this site. To determine the sex composition (based on genetic sexing) of CS gray whales and to assess whether matrilineal site-fidelity occurs in CS, we collected skin biopsy samples from 16 CS individuals ('residents') and 41 samples from other areas (representative of the overall population in the ENP: 'non-residents'). A total of 27 polymorphic sites defined 24 haploytpes among the 57 samples sequenced for HV1 of the mtDNA control region. The nucleotide and haplotype diversities of these samples were 0.017 (SE = 0.0012) and 0.94 (SE = 0.0019), respectively. Neighbor-joining analysis revealed five lineages each of which contained haplotypes that were observed in both residents and non-residents. Residents did not differ significantly from non-residents, and no significant sex-ratio bias was found. These data suggest a level of diversity that is inconsistent with a severe historical bottleneck, and given the available sample size, do not indicate matrilineally directed fidelity to Clayoquot Sound.