[env-trinity] SF Chronicle March 24

[Dan Bacher]

Byron

Very good article - many times better than the poorly done articles  
on the same issue in the Sacramento Bee!

Thanks
Dan
On Mar 24, 2008, at 7:17 AM, Byron wrote:

> Scientists try to explain dismal salmon run
>
> Jane Kay, Chronicle Environment Writer
>
> Monday, March 24, 2008
>
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>
> Amid growing concern over an imminent shutdown of the commercial  
> and sport chinook salmon season, scientists are struggling to  
> figure out why the largest run on the West Coast hit rock bottom  
> and what Californians can do to bring it back.
>
> The chinook salmon - born in the rivers, growing in the bay and  
> ocean, and returning to home rivers to spawn - need two essential  
> conditions early in life to prosper: safe passage through the  
> rivers to the bay and lots of seafood to eat once they reach the  
> ocean.
>
> Yet, the Sacramento River run of salmon that was expected to fill  
> fish markets in May didn't find those life-sustaining conditions.  
> And some scientists say that's the likeliest explanation for why  
> the number of returning spawners plummeted last fall to roughly  
> 90,000, about 10 percent of the peak reached just a few years ago.
>
> The devastating one-two punch happened as the water projects in the  
> Sacramento-San Joaquin River Delta pumped record amounts of  
> snowmelt and rainwater to farms and cities in Southern California,  
> degrading the salmon's habitat. And once the chinook reached the  
> ocean, they couldn't find the food they needed to survive where and  
> when they needed it.
>
> "You need good conditions in the rivers and ocean to get survival  
> and good returns for spawning," said Stephen Ralston, supervisory  
> research fisheries biologist with the National Oceanic and  
> Atmospheric Administration, or NOAA, and a science adviser to the  
> Pacific Coast Fishery Management Council.
>
> Without those favorable conditions, the salmon run crashed. Five  
> years ago, the peak was 872,700 returning spawners. Roughly 90,000  
> were counted in 2007, and only 63,900 are expected to return to  
> spawn in fall 2008.
>
> Helped by cool-water winter
>
> The fishery council, a regulatory body charged with setting fishing  
> limits, has recommended a full closure or a strict curtailment of  
> the commercial and sport season. A final decision will come in April.
>
> NOAA researchers say a cool-water winter will help the beleaguered  
> run in the future. An influx of cold Alaska waters, along with a  
> shot of nutrients from vigorous upwelling of deep waters, have been  
> fueling the food chain that feeds salmon, birds and marine mammals.
>
> But the scientists warn that chinook, which have swum through the  
> San Francisco Bay for thousands of years, have suffered human harm  
> over the past half-century and now also need human help.
>
> They've proposed a number of solutions, including sending more  
> water over the dams and reservoirs and down the tributaries where  
> salmon spawn; removing barriers to migration such as old dams;  
> screening the fish away from the pumps and diversion pipes that  
> suck them up, misdirect or kill them; controlling pesticide and  
> sewage pollution - and catching fewer fish while the populations  
> try to rebuild.
>
> Over the millennia, salmon have been born in the Central Valley  
> rivers. At about six months, they head through the delta. At 10  
> months and only 4-inches long, they reach the ocean and start  
> feeding voraciously in the Gulf of the Farallones on small shrimp,  
> krill and young rockfish.
>
> From there they move to the open waters from Monterey to Vancouver  
> Island in British Columbia until 3 or 4 years of age or older. Then  
> they return home to their birth river to reproduce and die. The  
> young come down the rivers, and the cycle begins again.
>
> The problems for the troubled fall run began in 2004 and 2005, the  
> years the chinook were born and traveled to the ocean. In those two  
> years, the federal Central Valley Project and the State Water  
> Project exported record amounts of delta water to urban and  
> agricultural customers in Southern California.
>
> 2005 a bad year for chinook
>
> In 2005, a crucial year for the young salmon, 55 percent of natural  
> river flows never made it out to the bay, according to records of  
> the state Department of Water Resources. The water was either  
> exported by the water agencies, diverted upstream of the delta or  
> held back by dams.
>
> "The flows were less than what the salmon needed, and the  
> populations are collapsing," said Tina Swanson, senior scientist  
> with the Bay Institute. Even if water agencies are meeting minimum  
> standards, they are inadequate to protect the fish, she said.
>
> A network of nonprofits, including the California Sportfishing  
> Protection Alliance, filed a notice Tuesday with the State Water  
> Resources Control Board, saying it would sue if it doesn't curb  
> pumping.
>
> But when looking for an answer to the fall run collapse, Jerry  
> Johns, deputy director of the state Department of Water Resources,  
> said there are many causes for the salmon's decline.
>
> "You can't just simply blame it on the pumps," he said. Ocean  
> conditions, a reduction of phytoplankton in the bay, the amount of  
> salmon fishing, natural die-off and other factors are part of the  
> broader picture, he said.
>
> There may have been increases in exports to water customers in  
> recent years, but the crucial point is whether there was also an  
> increase in rainfall and snowmelt, he said. That would mean there  
> was more water to divert.
>
> State and federal water project representatives say they follow  
> requirements put forth in their permits, which, among other things,  
> ensure a big enough water supply to protect endangered species and  
> provide certain minimum temperatures. They've aided the salmon by  
> removing dams, screening off diversion pipes and improving habitat.
>
> Biologists caution that salmon need generous flows of cold water at  
> almost every life stage. The fish also need the fresh river water  
> from the reservoirs at the right times, particularly in the fall  
> and summer.
>
> "The adults come upstream in the fall to spawn partly because  
> they're responding to cooler water temperatures," said Peter Moyle,  
> professor of fish biology at UC Davis. "If the females have to swim  
> through water that's too warm, their eggs don't mature as well.  
> Some don't hatch at all."
>
> Some females, Moyle said, just stop migrating and wait for cool  
> water. "They know from evolutionary perspective that if they don't  
> wait until the water gets cold, the young won't survive," he said.  
> In the end, they spawn or die before spawning.
>
> 'Squirrelly' ocean conditions
>
> According to Moyle, good ocean conditions can somewhat make up for  
> drought in the river systems and vice versa. But ocean conditions  
> have been "squirrelly" in the last several years with a number of  
> anomalies that produced abnormally warm conditions not good for  
> salmon, he said.
>
> "Usually, salmon populations are at their worst when conditions are  
> bad in both fresh water and salt water," Moyle said. Some  
> scientists think that is what happened to the 2007 fall run.
>
> Once in the ocean, salmon must gorge on small sea creatures to  
> survive.
>
> In 2005 and 2006, the years that the 2007 fall run needed food near  
> the shore in the Gulf of the Farallones, the upwelling of nutrients  
> apparently came too late to produce the small fish that feed the  
> salmon.
>
> Most of the scientists studying the ocean link the unexpected bouts  
> of rising temperatures to global warming. As the atmosphere and  
> oceans have warmed, researchers have had to discard the theory of  
> decades of warmer, then cooler, ocean temperatures. Now they expect  
> an unpredictability, which is projected in climate models.
>
> "What's happening is that the rockfish, the squid, the krill, the  
> anchovies and the community of critters that salmon feed on changed  
> dramatically in 2004 to the prey that is not as favorable to  
> salmon," NOAA's Ralston said.
>
> The distribution of the sea life also changed. Young rockfish moved  
> well to the north or to the south of Central California, he said.
>
> Ralston's hypothesis is that animals are adapted to finding food at  
> certain times and in certain locations. "When salmon arrive in the  
> ocean, they'll go to certain areas to find their food as they have  
> for millennia," he said. "If we have a major change, their fitness,  
> their ocean survival is compromised."
>
> Bill Peterson, a NOAA researcher in Newport, Ore., offered some  
> hope for a cooler offshore current, although he cautioned that  
> there would be a few years of hard times for chinook.
>
> "It's looking kind of good this year" with five months of cold  
> ocean currents, he said. But the scientists are "very guarded"  
> because in the past two years the ocean was cold in the winter, and  
> then the winds that brought upwelling quit in May and June,  
> reducing the zooplankton that feed the prey of the salmon.
>
> Peterson would like to see measures that would aid the salmon.
>
> "These fish are so resilient and tough," Peterson said. "We should  
> be a little nicer to them."
>
> Graphic: How a combination of river and ocean events during the  
> chinook salmon's life- cycle may have contributed to one of the  
> lowest counts on record in 2007 of the returning Sacramento River run.
>
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>
>
> Byron Leydecker
>
> Friends of Trinity River, Chair
>
> PO Box 2327
>
> Mill Valley, CA 94942-2327
>
> 415 383 4810
>
> 415 519 4810 cell
>
> 415 383 9562 fax
>
> bwl3 at comcast.net
>
> bleydecker at stanfordalumni.org (secondary)
>
> http://www.fotr.org
>
>
>
>
>
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