By Margaret Bauman
Researchers with the Alaska King Crab Research, Rehabilitation and Biology program have received $460,000 in grants and support to assess how wild red and blue king crab raised in hatcheries, in an effort to rebuild collapsed stocks, may fare in the wild.
The funds, announced Dec. 8 through the Alaska sea Grant program, will help in studies of how juvenile king crab cope with predators, find food, and interact with other marine organisms, including other crab.
Scientists with the program, known by the acronym AKCRRAB, working at the Alutiiq Pride Shellfish Hatchery in Seward, have steadily improved red king crab larval survival in the hatchery from two percent in 2007 to 31 percent in 2008 to 50 percent in 2009 and 2010. Some 100,000 red king crab have been raised to the first juvenile stage during the past two years.
AKCRRAB is a coalition of university and federal scientists, fishermen, seafood businesses, coastal communities, and Alaska Native groups that formed several years ago to find ways to help Kodiak Island red king crab and blue king crab in the Pribilof Islands recover.
Scientists at the Alutiiq Pride Hatchery in Seward have steadily applied that they’ve learned about water temperature, flow rate and artificial habitat- all designed to improve larval survival and hatchery productivity. They have also experimented with food, what kind, how much, and when to feed the growing crab.
In 2010, the adjustments have paid off with faster growth and improved survival of the larval red king crab. This year, 2.7 million red king crab were successfully hatched from some 18 female red king crab.
Ginny Eckert, associate professor of fisheries at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences, said the research is critical to evaluating the feasibility of rebuilding king crab stocks in waters around Kodiak Island and the Pribilof Islands. Scientists need to know how their crab would handle the rigors of life in the open ocean, she said.
“Hatchery-cultured red king crabs have no experience with seasonal cycles, predator avoidance techniques, or foraging for natural food items,” she said.
Eckert and Allan Stoner, research fisheries biologist with the federal Alaska Fisheries Science Center in Newport, Ore., received the two-year, $303,359 grant from the NOAA Sea Grant Aquaculture Research Program. Additional in-kind and support services totaling $156,706 come from the Alutiiq Pride Shellfish Hatchery, the Alaska Department of Fish and Game, the University of Alaska Fairbanks, and Alaska Sea Grant.
Part of this new research will explore whether conditioning juvenile crab to predators improves survival, Eckert said.
Over the next two years, Eckert and others will conduct experiments aimed at better understanding the role of habitat, crab body size, prey density, predator density, water conditions, and predator types on the survival of juvenile crab. Lab experiments will be done at the Hatfield Marine Science Center in Newport, Ore., and field experiments in Yankee Cove, near Juneau.
Raising and then releasing large numbers of hatchery-born king crab into the wild is not currently part of the AKCRRAB program.
The program focuses instead on determining the feasibility of hatcheries as a tool to rebuild wild crab stocks. Should hatcheries be a feasible rebuilding tool, resource managers and policymakers would have to decide whether to use them.