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Juvenile Blue King Crab. Photo Jim Swingle/AKCRRAB
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In the
latest update from the king crab rearing program at the Alutiiq Pride Hatchery
in Seward, researchers have been gauging survival rates based on population
densities.
Ben Daly is
an Alaska Sea Grant Program research biologist with the University of Alaska
Fairbanks, based in Seward. He said that generally the lower the density, the
higher the survival rate.
-- (Crab 1 39 sec "But,
that doesn't mean ... magic combination of those things.")
The latest
study showed Pribilof Blue King Crab had a survival rate of 85 percent when
reared at a density of 200 crab per square meter. Tests of survival at
different densities have seen as many as 6,000 crab per square meter, and
survival rates around 20 percent.
One factor
affecting survival rates is the high level of cannibalism among the crab,
especially at higher densities:
-- (Crab 2 38 sec "The
juvenile are extremely ... in the wild, I would suspect.")
The AK-CRAB
program is a joint venture by the Alaska Sea Grant College Program, UAF School
of Fisheries, NOAA Fisheries, and the Alutiiq Pride Shellfish Hatchery, as well
as community and industry groups. The ultimate goal is to some day restock
depleted Kodiak Red King Crab and Pribilof Blue King Crab with hatchery-reared
crab. Daly says the technology and technique is probably ready:
-- (Crab 3 38 sec "I
would say the hatchery science ... are there, currently.")
Updates
earlier this year have measured how seafloor terrain complexity affects
predation on young crab by older ones, and how growth rates are affected by
differing water temperatures. They found that the more complex seafloor
environment reduced predation, and that young crab grew faster in warmer water.
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