Red king/blue king: why crab enhancement is so important to Alaska.

• Author: Vick, Gale K.

What is it about "king crab" that is so evocative of Alaska? Glorious history. Images of king crab bring up largess, days that we thought would never end, mountains of crab bringing a double bounty of food and income from Southeast to the Bering Sea.

But the glory days of a crew making more than $100,000 in a season and boat owners making millions of dollars are gone. While some species of crab are still abundant in Alaska, and there continues to be a red king fishery in Bristol Bay and Southeast Alaska, the giant red kings (Paralithodes camtschaticus) of Kodiak (that once grew to 20 pounds with more than 6-foot leg spans) and the blue kings (P. platypus) of the Pribilof Islands have long been closed to commercial fishing, victims of debated causes.

There is hope, however, that current research regarding the potential to enhance wild stocks through the cultivation of early stage crab juveniles released into the wild might bring those days back.

WHY STOCKS ARE DEPLETED

First, it is important to try to understand why the stocks have not rebounded. There is much speculation about what may have caused such dramatic crashes but few answers. A renowned crab scientist, Dr. Gordon Kruse (University of Alaska Fairbanks), said in a recent interview, "We've been working on rebuilding red king crab stocks for almost 25 years by closing commercial fishing and creating protection zones. We don't have much to show. Grants from the North Pacific Research Board and the Alaska Sea Grant are now enabling us to review stock-reconstruction data on population dynamics since the mid-1950s. Bill Bechtol, a graduate student, is seeking to provide an analysis of that data which could illustrate the relationship of stock fluctuations to a variety of factors, including water temperate, fishing effort, and predation."

TEMPERATURE COUNTS

Kruse thinks a perhaps overdue decadal climate shift of 1 to 2 degrees C cooler might provide more optimal survival conditions as crab are very sensitive to water temperatures. But, he said, predators like halibut, sculpin, Pacific cod, arrowtooth flounder and even salmon could be real culprits in keeping crab recruitment low. In Southeast Alaska, sea otters have a major impact. In a 1999 radio interview, Branden Kelly, a UAF marine scientist, reported "Sea otters are loved by tourists and others because they are incredibly cute. But beneath that cuddly fur coat lurks an insatiable appetite for crab, abalone, sea urchins and other marine life."

As a potential solution to predation, Dr. Kruse notes, "We need to consider habitat measures that would provide hideouts for juvenile crab. A fellow scientist, Braxton Dew (NMFS), found that dock pilings in Kodiak held a potential for creating an enhancement environment."

WHY REBUILD STOCKS?

Why put this kind of effort into rebuilding stocks? Because it can provide a lucrative resource for commercial, sport and subsistence use. Of the 10 species of crab caught all over Alaska, (seven with commercial importance--red king, blue king, golden king, Tanner crab (bairdi), snow crab (opilio), hair crab and Dungeness crab; and three minor species--scarlet king, grooved Tanner and Triangle Tanner), the red and blue king crab have the greatest history of commercial value.

According to the Alaska Department of Fish and Game, "historically, the red king crab fishery has been Alaska's top shellfish fishery. Since statehood in 1959, U.S. fishers have harvested nearly 2 billion pounds of red king crab worth $1.6 billion from Alaska waters, making red king crabs the second most valuable species, next to salmon, to fishers during this period." The Kodiak Chamber of Commerce states, "In 1950, 60,000 pounds of king crab were landed. The king crab fishery became a major force in Kodiak's economy from 1950 to 1959 as the catch increased from 60,000 to 21 million...