The biggest fishery for Seattle-based trawler fleets is likely to face cuts next year as the pollock population declines.

The biggest fishery in North America is likely to take a big tumble next year as a result of ocean surveys that show a sharp decline in abundance of Bering Sea pollock.

The fish, which is processed into fillets, surimi paste and other products, typically brings in more than $1 billion in annual revenue and is a mainstay of Seattle-based trawl fleets.

Bering Sea pollock populations have been on decline for several years, and that downturn appears to have accelerated. Recent acoustic surveys by NOAA Fisheries indicate the 2008 pollock population was 38 percent below last year’s survey levels.

The new surveys are expected to influence the North Pacific Fishery Management Council — a mix of federal, state and industry officials — when it meets in December to set the final harvest levels for 2009.

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Some fishermen expected the harvests will drop to about 800,000 metric tons, which would be the smallest harvest in more than 30 years, and a steep decline from the 1.5 million metric-ton record harvest just three years ago.

Pollock are a white-fleshed fish that congregate in huge schools along the continental shelf of the Bering Sea. They are processed by factory trawlers as well as by trawlers that deliver to shore plants or floating factory ships.

In 2005, pollock gained an eco-label and a marketing boost when certified through the Marine Stewardship Council as a sustainable harvest.

Some federal scientists are hopeful that the recent pollock declines are cyclical, and predict that 2010 could see at least a modest upswing in populations as a strong class of young pollock — born in 2006 — matures.

“I don’t think we’re overfishing,” said Jim Ianelli, a federal scientist and pollock specialist with the Seattle-based Alaska Fisheries Science Center, which conducts the acoustic surveys.

The North Pacific council has never exceeded pollock- harvest levels recommended by scientists.

But federal management of the fishery — and the Marine Stewardship certification — has been challenged by Greenpeace, whose scientists think the pollock catches have been much too large.

“We are on the cusp of one of the largest fishery collapses in history,”said John Hocevar, a marine biologist and director of the Greenpeace Oceans Campaign.

Greenpeace has placed pollock on a “red list” of unsustainable harvests, and urged seafood retailers to join in a bid to overhaul management.

At the December council meeting, Greenpeace is likely to lobby to set the 2009 harvest at half the 2008 harvest level, Hocevar said.

He noted that pollock is a food source for Steller’s sea lions, fur seals and other species, and that a pollock crash could have a wide-ranging effect on the broader Bering Sea ecosystem.

Climate change also is a new wild card, with a string of abnormally warm water years. The last few years, however, brought colder temperatures to the Bering Sea, according to Ianelli.

Hal Bernton: 206-464-2581