Diet Supplementation Boosts Blue King Crab Survival Rate

at the Alutiiq Pride Shellfish Hatchery in Seward, Alaska, are reporting great success
culturing blue king crab this spring. They credit their progress with investigation
of effects of microalgae diet supplementation on survival and larval health.
found that a diet of live Thalassiosira weissflogii microalgae and enriched Artemia
resulted in survival rates of 80 percent from matching to the glaucothoe stage and
53 percent from matching to the first juvenile stage.
survival rates are the highest to date for either red or blue king crab since the
project began, they said.
this year, large-scale culture of blue king crab was less successful than for red
king crab. High rates of mortality were attributed to suboptimal hatchery rearing
conditions. While the life histories of red and blue king crab are similar, different
culturing protocols may be required to achieve similar production success, they
project is one of several underway through the Alaska King Crab Research, Rehabilitation
and Biology program, also known as AKCRRAB, sponsored by industry members, community
groups, the Alutiiq Pride Shellfish Hatchery, NOAA Fisheries, the University of
Alaska Fairbanks School of Fisheries and Ocean Sciences, and the Alaska Sea Grant
College Program.
high survival of red king crab has been achieved without microalgae in the diet,
microalgae may be essential for blue king crab larvae. However, use of microalgae
in large-scale, flow-through systems poses logistical challenges because of their
small cell size, which allows algae to be quickly flushed out of the tanks. To solve
this problem, AKCRRAB biologists Jim Swingle and Den Daly developed a semi-static
rearing technique where microalgae is retained in tanks to optimize larval exposure,
they said.
blue crab cultured at the Seward hatchery will be used in experiments to better
understand the biology of early juvenile king crab at NOAA Alaska Fisheries Science
Center Behavioral Ecology Lab in Newport, Ore., the NOAA Kodiak Fisheries Research
Center, and the University of Alaska Fairbanks, Juneau Center.