Blue king crab rearing yields high survival at Alutiiq Pride Shellfish Hatchery
Juvenile blue king crabs had an 85% survival after a 10 week nursery grow-out period at the Alutiiq Pride Shellfish Hatchery in Seward. The blue king crab larvae were hatched from ovigerous females collected in the commercial fishery off St. Matthew Island, and were reared to the first juvenile stage at NOAA Fisheries in Kodiak. The juveniles were then shipped to Seward and reared at a density of 200 crabs per square meter—a low density compared to previous years. With identical diet and temperature, juvenile blue king crab rearing in 2008 yielded 50% survival at a density of 1,300 crabs per square meter for seven weeks. Juvenile red king crabs reared at the hatchery from 2008 to 2010 at higher densities had even lower survival. For example, red king crabs reared at 4,000 crabs per square meter had 21% survival after eight weeks.
Stocking density undoubtedly has strong effects on hatchery survival. Future studies are needed to determine what combination of survival rate and density could maximize production per unit effort for blue king crab, especially when considering floor space and cost of pumping, filtering, and heating seawater.
News Flash is edited by Ben Daly. AKCRRAB is a research and rehabilitation project sponsored by the Alaska Sea Grant College Program, UAF School of Fisheries and Ocean Sciences, NOAA Fisheries, the Alutiiq Pride Shellfish Hatchery, community groups, and industry members. For more information go to http://seagrant.uaf.edu/research/projects/initiatives/king_crab/general.