ANCHORAGE — State fisheries biologists have launched a study into the habits of Alaska’s most valuable groundfish — at least by price per pound — in southcentral Alaska waters.
The Alaska Department of Fish and Game this month caught, tagged and turned loose 1,200 sablefish in Prince William Sound. Biologists hope commercial and sport fishermen who catch them next time will turn in tags inserted at the base of their dorsal fins, along with information on where, when and how deep they caught them.
The goal is to determine whether Prince William Sound sablefish are homebodies, said research biologist Dr. Kenneth J. Goldman.
“What we’re after is to learn whether sable fish from Prince William Sound are well-mixed with the larger part of the population in the Gulf of Alaska as a whole,” he said from his office in Homer.
If most sablefish mix with gulf fish, the state can rely on federal surveys from the gulf to make management decisions such as catch limits. If sablefish mostly stick around without ranging into the gulf, the state may have to plan more extensive studies of its own.
“If mixing rates are low, that tells me we have some assessment work to do in Prince Williams Sound,” Goldman said.
Sablefish are known by a variety of names, including black cod. They don’t belong to the cod family but they hang out with them in deep water, feeding on fish, squid, octopus, and crustaceans.
Another name, butterfish, hints at why they’re considered a delicacy. Sablefish have a rich oil content that makes them flavorful and well-suited for smoking. Many are shipped to Japan.
The biggest caught was 44 inches and 25 pounds but their average weight last year in southeast Alaska was about 8 pounds. They’re also long-lived. The oldest to be caught in U.S. waters, off Alaska’s coast, was estimated to be 94 years old, based on examining and counting growth rings in the otolith, a bone in the skull that helps fish maintain equilibrium.
Commercial fisherman catch them using “longlines,” multiple, baited hooks stretched out on lines thousands of feet long. Sperm whales, the largest of the toothed whales, and killer whales sometimes steal hooked sablefish, leading some commercial fishermen to use baited pots where they’re allowed.
Fishermen in southeast Alaska sold dressed sablefish for an average of $5.96 per pound last year. The catch in state-managed waters was just more than 2 million pounds, including 1.6 million pounds in Southeast and 212,182 pounds in Prince William Sound.
That’s a fraction of the catch taken in federally managed waters farther offshore. Fishermen reported a total catch of 21.9 million pounds, including 7.9 million pounds in the central Gulf of Alaska and 5.7 million pounds in outside waters of southeast Alaska.
State technicians used pots in the Prince William Sound tagging project, Goldman said. Similar surveys in Southeast found that sablefish caught with hooks and tagged became “hook shy” and eluded recapture.
He hoped to tag 3,500 fish but ended up with 1,200 in 10 days of fishing on a variety of sites around Prince William Sound sites.
He calls that a good “starter kit” before this year’s Prince William Sound sablefish commercial season, which begins April 15 and runs through the end of August.
Anglers and commercial fishermen who turn in tags will be rewarded with a free cap and entered for five $100 prizes at the end of the season, Goldman said.
The sablefish study will run for three years if funds are available.