Poor ocean conditions blamed for salmon decline
Ocean conditions three years ago that included abnormal winds and warmer temperatures caused the record low number of Chinook salmon to return to the Yuba River and the entire West Coast last fall, fishery scientists said Monday.
The poor conditions in 2005 are part of increasing variability in the ocean’s patterns that scientists have seen in the past 10 years.
“You can’t predict anything,” oceanographer Bill Peterson, of the U.S. National Oceanic and Atmospheric Administration (NOAA). Peterson studies plankton for the Seattle-based Northwest Fisheries Science Center, affiliated with NOAA.
In 2005, unusual wind patterns and currents delayed the spring upwelling of nutrients to the ocean’s surface. That upwelling produces plankton, or small animal and plant life, that supports the entire aquatic food web.
Without plankton to feed small fish such as anchovies, herring and smelt, larger animals like salmon and sea birds starved.
That same year, countless seabirds, including Cassin’s auklets, common murres and commorants, washed up dead on beaches, and birds built sparse nesting colonies, the Associated Press reported.
In addition, water temperatures near the Oregon coast, where Chinook salmon spend much of their ocean time, were 5 to 7 degrees warmer than normal. That area of ocean yielded about one-fourth the usual amount of phytoplankton.
“We had the lowest plankton abundance I’ve ever seen,” Peterson said. “There was nothing to eat in the ocean.”
As a result, “salmon that went to sea in 2005 didn’t make it,” Peterson said.
The 2005 generation of young fish would have come back upriver to spawn in fall 2007. But the number of Chinook salmon in last year’s fall run was one-third of what biologists had expected on the Yuba, Feather and Sacramento rivers.
In 2007, 2,600 Chinook salmon spawned on the lower Yuba River compared to 18,000 Chinook salmon in 2005, according to carcass counts conducted by the California Department of Fish and Game.
Fishery chiefs meet next week
The commercial and sport fishing industry has been reeling, even before the 2005 conditions clobbered last fall’s salmon run.
Salmon fishing off California and most of Oregon was valued at an average of $103 million a year from 1979 to 2000, but dropped to $61 million a year from 2001 to 2005, according to council figures.
While ocean conditions are critical to salmon survival, other factors also limit salmon populations, said Gary Reedy, a river scientist for the South Yuba River Citizens League.
“People tend to throw their hands up. That would be a big mistake, to act as if there’s nothing we can do,” Reedy said.
Building salmon resiliency to adverse environmental conditions, restoring more complex riparian habitat and providing historical access upstream can also improve salmon populations, Reedy said.
Next week, federal fisheries managers will meet in Sacramento to set options for commercial, sport and tribal fishing off the coasts of California, Oregon and Washington. The Pacific Fishery Management Council will set the final seasons when it meets in Seattle in April.
While no decisions have been made, there are likely to be some salmon fishing closures, according to Chuck Tracy, a salmon staffer for the council.
Good salmon runs aren’t expected to return until at least 2009 or 2010, yet upwelling conditions appear to look good this year based on storm indications coming from the north and west, Peterson said.
“I think this is the year people come to realize the ocean has a very powerful influence over the salmon,” Peterson said.
The Associated Press contributed to this report. To contact Staff Writer Laura Brown, e-mail firstname.lastname@example.org or call 477-4231.
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