Researchers improve king crab culture technology
May 24, 2012
907-474-5703
5/24/12
AKCRRAB biologists had great success culturing blue king crab at the Alutiiq Pride Shellfish Hatchery this spring. They investigated the effects of microalgae diet supplementation on survival and larval health. A diet of live Thalassiosira weissflogii microalgae and enriched Artemia yielded an exceptional survival of 80 percent from hatching to the glaucothoe stage and 53 percent from hatching to the first juvenile stage (C1). These survival rates are the highest to date for either red or blue king crab since the beginning of the AKCRRAB project.
Before this year, large-scale culture of blue king crab has been less successful than for red king crabs. High rates of mortality were attributed to suboptimal hatchery rearing conditions. Though the life histories of red and blue king crab are similar, different culturing protocols may be required to achieve similar production success. For example, high survival of red king crab has been achieved without microalgae in the diet, but microalgae may be essential for blue king crab larvae. However, the use of microalgae in large-scale, flow-through systems poses logistical challenges because of their small cell size, which allows the algae to be quickly flushed out of the tanks. To solve this problem, AKCRRAB biologists Jim Swingle and Ben Daly developed a semi-static rearing technique where microalgae is retained in tanks to optimize larval exposure.
The juvenile blue king crabs cultured at the hatchery will be used in experiments to better understand the biology of early juvenile king crabs at the NOAA Alaska Fisheries Science Center Behavioral Ecology Lab in Newport, Oregon, the NOAA Kodiak Fisheries Research Center, and the University of Alaska Fairbanks, Juneau Center.