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Fish Factor

World's foremost crab scientists share home grown crab findings
By Laine Welch


April 03, 2006

People are already growing crops of king crab in several countries around the world. But tracking how well the home grown crabs might survive in the wild remains one of the biggest mysteries. That was just one of the fascinating findings shared by the world's foremost crab scientists future at a first of its kind gathering two weeks ago in Kodiak.

In Japan, for example, researchers ten years ago produced half a million king crab larvae in large hatchery vats. The small crabs were eventually placed in bags in the ocean to harden and after several months, they were released into the ocean. But no follow up was done, so nothing is known about their survival.

jpg golden king crab

Golden king crab (Lithodes aequispina), such as these, were observed in abundant numbers at the upper elevations (generally above 500 meters) of the Patton Seamount in the Gulf of Alaska during the 1999 Patton seamount expedition. Most of the adults were observed on rocky substrates, and grasping pairs were seen on several submersible dives.
Photo courtesy National Marine Fisheries

Russian researcher Nina Kovacheva of Moscow has developed a closed recirculation system for king crab that has yielded a 35 percent survival rate through the first stage of development. Her team is now raising 2,000 juvenile crabs in a 1,500 square meter pen on the sea floor (about half the size of a football field). The Russian scientists are also using a system of 42 floating tanks, each holding about 40 pounds of king crab.

Gustavo Lovrich of Argentina, who focuses on golden king crab, has discovered that good aeration and water quality are keys to their survival. Likewise, Dr. Kurt Paschke of Chile has learned that tiny golden king crabs grow best when they are raised in the dark, because they spend less energy swimming. Paschke raises his crabs in salmon egg trays using upwelling water, with densities of up to 800 crabs per tray. He has found that with good water exchange, fast growers may reach 100 millimeters in 3.5 years. Paschke hopes to soon produce over 19,000 golden crabs per year.

Closer to home, Dr. Tom Shirley at the University of Alaska/Fairbanks School of Fisheries and Ocean Sciences (Juneau campus) has discovered that golden king crabs produce eggs that are 20 times the size of red king crab, and that the newly hatched eggs contain large quantities of lipid (fats). Consequently, they don't need to feed and can live more than six months without doing so. Also in Alaska, Dr. Brad Stevens has raised several hundred red and blue king crab in PVC tubes and beakers over four years at the federal Near Island Research Facility at Kodiak. He said one of his biggest challenges is refining their diet of brine shrimp and diatoms.

Stevens credited researcher Gro van der Meeren of Norway with giving the group a "reality check." She pointed out that few crab enhancement programs have been successful due to a lack of ecological understanding. The goal is simple: to release small crabs, and allow them to grow to maturity and recapture them. She told the group that the animals must first be adapted to their new conditions in the wild. They need to be released under correct light and temperature conditions, they need to find shelter immediately, and the habitat must be appropriate. Stevens added: "We need to give hatchery raised crabs the chance to acquire adaptive behaviors by challenging them in the lab with natural habitats, foods and predators. And in order to determine the effectiveness of such a program, we need a method to mark hatchery raised crabs in order to distinguish them from wild crabs."

Stevens said it is certainly possible to enhance king crab stocks in Alaska, but it would require a large financial outlay. "I'm guessing $20 million for a facility and operating costs of $2 - $3 million a year. Those are government estimates," he said, adding that the cost would likely be far less if a project was undertaken by fishermen.

Stevens said, "If you started with 200 females, you could expect to produce 30 million larvae. Survival to the first crab stage might range from 25 to 75 percent, and survival to maturity or capture size about eight years later might range from three to 25 percent if you're lucky. At current prices, that should produce a benefit to cost ratio of from one to ten. If you're a banker and your goal is to make money, you say this is not the best investment. But if your goals are to maintain fishing opportunities, to re- establish depleted populations, to provide employment for fishermen and their offspring, to maintain the socioeconomic structures of coastal communities, and to produce a high quality seafood product , then maybe it would be a good thing."

WILD SALMON CAR WINS! The Wild Alaska Salmon race car won the March 28 race at the Miami Grand Prix. Sponsored by 10th & M Seafoods of Anchorage and Emory Motorsports of Oregon, the big win followed a third place finish in the Rolex series a few weeks before. Tenth and M owner Skip Winfree said he has received more than 4,000 calls and emails seeking more information about the racing Porsche. He credits the Wild Salmon logo with a 20 percent increase in online orders for his seafood market since it began appearing on the race circuit last year. Winfree is hopeful that the Alaska salmon industry will put up some money for the sponsorship, or it might be bumped in favor of other paying sponsors who are clamoring to get their names on the winning car.

SALMON SWEEPSTAKES ­ In another tribute to wild salmon, Alaska Airlines will celebrate the "official" start of the season next month with a Copper River sweepstakes. The promotion is aimed at touting the famous fish as "one of the nation's most prized healthy foods," as well as the role the airline plays in delivering Alaska seafood to customers.

Twenty sweepstakes winners will each receive 20 pounds of Copper River salmon fillets from Prime Select Seafoods of Cordova. The grand prize winner will receive a fishing adventure for four hosted by Cordova's Alaskan Wilderness Outfitting Company. Last year Alaska Airlines transported more than 30 million pounds of Alaska seafood to markets in the U.S., Canada and Mexico.

OH MY, THOSE OMEGAS! Seventy-eight percent of Americans recognize that omega-3 fatty acids found in some fish (and some fortified foods) may reduce the risk of heart disease. That's according to a survey of 1,060 people aged 18 or older conducted by the International Food Information Council.

Meanwhile, another study in Britain has added to earlier claims that omega-3s in fish oils can help with children's behavioral problems. reports that a group of 25 youngsters aged 12 to 15 with severe attention deficit/hyperactivity disorder (ADHD) were given fish oil supplements for three months. Before the trial began, 94 percent of the subjects had high ratings for inattention and impulsivity. After taking the fish oil supplements, the severe impulsivity was cut to 28 percent and severe inattention fell to 17 percent. The lead researcher, Madeleine Portwood, called the results "stunning." Portwood conducted a similar study on younger children aged 18 months to 30 months and found omega 3 supplements improved their behavior.


Laine Welch has been covering news of Alaska's seafood industry since 1988. Her Fish Factor column appears weekly in over a dozen papers and websites. Her Fish Radio programs air on 27 stations across Alaska.

Contact Laine at msfish[AT]

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