(01-29) 12:14 PST San Francisco (AP) --
The number of chinook salmon returning to California's Central Valley reached a near-record low last year, pointing to an "unprecedented collapse" that could lead to severe restrictions on West Coast salmon fishing this year, according to federal fishery regulators.
The sharp drop in chinook or "king" salmon returning from the Pacific Ocean to spawn in the Sacramento River and its tributaries this past fall is part of broader decline in wild salmon runs in rivers across the West.
Regulators are still trying to understand the reasons for the shrinking number of spawners; some scientists believe it's related to changes in the ocean linked to global warming.
Only about 90,000 returning adult salmon were counted in the Central Valley in 2007, the second lowest number on record, according to an internal memo sent to members of the Pacific Fishery Management Council and obtained by The Associated Press. That's down from about 277,000 in 2006 and an all-time high of 804,000 just five years ago.
In an e-mail to council members, Donald McIsaac, the agency's executive director, said he wanted to give them "an early alert to what at this point appears to be an unprecedented collapse in the abundance of adult California Central Valley ... fall Chinook salmon stocks."
"The magnitude of the low abundance ... is such that the opening of all marine and freshwater fisheries impacting this important salmon stock will be questioned," he said.
It's only the second time in 35 years that the Central Valley has not met the agency's conservation goal of 122,000 to 180,000 returning fish, according to the council, which regulates Pacific Coast fisheries.
More worrisome is that only about 2,000 2-year-old juvenile chinooks — used to predict returns of adult spawners in the coming season — returned to the Central Valley last year, by far the lowest number ever counted. On average, about 40,000 juveniles or "jacks" return each year.
Salmon that spawn in Central Valley rivers form the backbone of the West Coast's commercial and recreational salmon fishery and are caught by fisherman as far north as British Columbia,
"Sacramento fish are really what the fishery depends on," said Chuck Tracy, who heads the council's salmon technical team. "When Central Valley fish are low it gets really hard to catch fish even if you're given the opportunity."
The council plans to meet in Sacramento in March to discuss possible restrictions on the salmon season that begins in May. Final decisions will be made at its meeting in Seattle in April.