Survey- and Fishery-Derived Estimates of Pacific Cod (Gadus macrocephalus) Biomass: Implications for Strategies to Reduce Interactions Between Groundfish Fisheries and Steller Sea Lions (Eumetopias jubatus)

Steller sea lion populations in western Alaska have declined over the last 30 yr and are now considered to be threatened. Concern that one possible cause may be local depletion of prey by commercial fisheries has led to controversial groundfish fishery restrictions. Survey- and fishery-derived biomass estimates of Pacific cod suggest that harvest indices in part of the Steller sea lion critical habitat in February and March 2001 were 5-16 times greater than the annual rate for the entire Bering Sea-Aleutian islands stock. Fishery effects on prey availability across the temporal and spatial scales relevant to foraging sea lions may be much greater than the effects that would be indicated by annual harvest rates determined from stock assessments averaged over the target species range.