Ancient DNA reveals genotypic relationships among Oregon populations of the sea otter (Enhydra lutris)

The sea otter has experienced a dramatic Population decline caused by intense human harvesting, followed by a century of recovery including relocation efforts to reestablish the species across its former range in the eastern Pacific. Although the otter was historically present along the coast in Oregon, there are currently no populations in this region and reintroduction efforts have failed. We examined the mtDNA genotypes of 16 pre-harvest otter samples from two Oregon locations in an attempt to determine the best genotypic match with extant populations. Our amplifications of a 222 base-pair portion of the control region from otters ranging in age from approximately 175-2000 years revealed four genotypes. The genotypic composition of pre-harvest otter populations appears to match best with those of contemporary populations from California and not from Alaska, where reintroduction stocks are typically derived.