El Niņo Stirring, Salmon at Riskby Les Blumenthal
The News Tribune, August 23, 2004
WASHINGTON -- An El Niņo stirring in the Pacific Ocean could pose a threat to Northwest salmon and provide a crucial test of the federal plan to revive runs on the Columbia River and elsewhere.
The record or near-record runs of the past several years are primarily the result of favorable ocean conditions. An El Niņo event, even a moderate one like that currently predicted, could reverse the trend, scientists say.
Earlier this summer, a string of weather buoys stretching across the Pacific from New Guinea to the Galapagos Islands detected a warming in surface waters, the first signs of a possible El Niņo, a disruption of the prevailing oceanic and atmospheric trends.
Though the increase was slight, roughly 1 degree above normal, the National Weather Service's Climate Prediction Center said it could "indicate the possible early stages of a warming episode."
The agency also said the normal easterly winds that blow across the equatorial Pacific in mid-June and early July had weakened, another possible sign of an El Niņo.
El Niņo can affect weather patterns around the globe, producing droughts in Indonesia, Australia and Africa, strong storms in California and unusually dry conditions in the Northwest. Ocean temperatures off the Northwest coast can increase, cool northerly winds can be replaced by warmer winds from the southwest, rainfall can taper off and stream flows can drop.
During the last strong El Niņo in 1997-98, fish normally found in warmer waters like great white sharks and yellowtail tuna were found as far north as Alaska. That El Niņo resulted in an estimated $20 billion in damage around the world.
Scientists say their models show an even chance an El Niņo will occur within the next three to six months.
"It's just beginning to develop and it looks like a weak event," said Vern Kousky, a research meteorologist with the National Oceanic and Atmospheric Administration.
Though Kousky said he didn't think it would affect salmon runs in the Pacific Northwest, others weren't so sure.
"When you have an El Niņo, salmon survival in the Northwest seems to be less," said Alan Hamlet, a research scientist with the Climate Impact Group at the University of Washington. Hamlet said there is "considerable evidence" a moderate El Niņo is developing.
Since the 1997-98 El Niņo faded, salmon have thrived as the cool ocean waters off the Northwest coast have produced an abundance of krill and other food.
Last year, more than 900,000 chinook salmon passed Bonneville Dam on their way to upstream spawning grounds, the largest return since the dam on the Columbia River was completed in 1938. Steelhead and coho returns on the Columbia also have been well above their 10-year average. Healthy runs have been reported on other streams and rivers in the region, including those along Puget Sound.
No one knows if a new El Niņo will be strong enough to spread its warm water along the Northwest coast. If it does, salmon, which spend two or three years in the ocean, could face a less hospitable environment.
"A normal salmon season can be interrupted by El Niņo," said Bill Peterson, a NOAA oceanographer based in Newport, Ore.
Every two weeks, a research vessel departs from NOAA's Newport facility to sample water temperatures and make other observations.
Even if warmer water doesn't arrive, Peterson said, a shift in wind patterns associated with an El Niņo could affect ocean conditions. The normal winds out of the north keep the ocean cool and produce the strong upwelling that carries salmon food to the surface. They could be replaced by warmer winds from the southwest.
El Niņos can also produce drier winters and springs, which in turn hurt juvenile salmon and steelhead migrating downstream by reducing stream and river flows.
Those in charge of the effort to rebuild the runs are making no firm predictions.
"I don't trust the weather forecasters," said Steve Wright, who heads the Bonneville Power Administration.
The existing plan for reviving the salmon runs on the Columbia and Snake rivers has been controversial, and a federal judge in Portland has told NOAA to rewrite it. NOAA's draft of its new plan is scheduled to be delivered to the court by the end of August.
The current plan focuses on increased spilling of water over the dams to help downstream migration of juveniles, improving spawning habitat and dozens of other activities to help the salmon.
Because of the fish-friendly ocean conditions, no one is sure whether any of those steps have helped. But if the good ocean conditions fade because of El Niņo, scientists should get a more accurate picture of whether the federal plan has worked.
"This is like a natural experiment," Peterson said.
What is an El Niņo?
El Niņo is a disruption of the ocean-atmosphere system in the tropical Pacific that has important consequences around the world.
What's the origin of the name? The phenomenon was originally recognized by fishermen off South America as the appearance of unusually warm water in the Pacific. It was dubbed El Niņo, which means The Little Boy or Christ Child in Spanish, because of the tendency to occur around Christmas.
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