Genetic data reveal mixed-stock assemblages of gray whales (Eschrichtius robustus) in both the Eastern and Western Pacific Ocean
Anna Brunche-Olsen, Jorge Urban R., Vladimir V. Vertyankin, Celine A. J. Godard-Codding, John W. Bickham and J. Andrew DeWoody
International Whaling Commission
Western gray whales are critically endangered whereas the Eastern gray whale is relatively common. Both were severely affected by Holocene environmental changes and commercial whaling, but gray whales in the Eastern Pacific now outnumber their Western counterparts by more than 100x. Herein, we investigate the genetic diversity and population structure within the species. Results indicate the gray whale gene pool is differentiated into two lineages, that each lineage contains similar levels of genetic diversity, and that both our Eastern and Western geographic samples were derived from mixed-stock aggregations composed of two distinct lineages. Overall, our data are inconsistent with the idea that the gray whale gene pool consists of a single population at equilibrium.