Mitochondrial DNA Diversity Gradient Among North Pacific Populations of Red King Crab

Red king crab, a ‘deadliest catch’ species, supports the largest invertebrate harvest in Alaska. However, abundances of this crab have declined in several areas, leading to the closure of harvests in some areas, particularly in the Central Gulf of Alaska. Genetic information can support the management of red king crab by helping to define independent populations and by identifying populations with low genetic diversity that may be at genetic risk of decline. In this study, sequence variability of maternally inherited mitochondrial DNA (COI, 665 bp) was surveyed in samples from 18 locations extending from the Sea of Japan to Southeast Alaska. This survey revealed strong clines in haplotype (h = 0.98–0.27) and nucleotide (Θ_π  = 0.0102–0.0004) diversities, with the largest genetic diversities in the Northwestern Pacific and Bering Sea, intermediate diversities in the Central Gulf of Alaska and low diversities in Southeast Alaska. The analysis of molecular variance (AMOVA) detected heterogeneity among populations in the Bering Sea and Southeast Alaska, but no heterogeneity among populations in the Central Gulf of Alaska. These results indicate that in some regions red king crab populations must be managed on a small geographic scale. These results also provide guidance for possible stock enhancement efforts.