Sea Lions had Salmon Feastby Associated Press
Spokesman Review, June 10, 2007
Predators ambushed chinook at Bonneville
PORTLAND - California sea lions have eaten what appears to be a record number of spring chinook salmon at Bonneville Dam, the U.S. Army Corps of Engineers reports.
Hazing efforts to keep the sea lions from the schooled-up salmon searching for fish ladders to help them upriver to spawn have ended for the season. Most of the sea lions also have left.
The efforts included explosions on and under the water, rubber buckshot and beanbag rounds fired from shotguns.
Researchers observed 3,557 salmon taken below the dam. The previous record in the six years observations have been made was 3,533 in 2004 - 1.9 percent of the run that year.
This year predation below the dam is expected to be 4.1 percent because the run was smaller.
"We had a relatively low fish run" this year, said Robert Stansell, who heads up the research effort for the U.S. Army Corps of Engineers, which operates the dam.
The male sea lions have appeared at the dam in growing numbers in recent years, apparently because of an increase in the size of the spring chinook run.
One sea lion with the brand C265 was trapped and weighed near the river mouth in March at 559 pounds. He was found there again after spending more than two months below the dam and weighed 1,043 pounds.
He has been seen at the dam annually since 2002.
Observers this year identified up to 51 California sea lions at the dam on any one day.
"Evidence suggests that the increased harassment program this year did not have an overall substantial impact on reducing predation in the tailrace below Bonneville Dam nor the number of sea lions," the Corps of Engineers concluded.
"Whether or not more salmonids would have been taken without this effort is unknown."
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