STEVENSON, Wash., April 14 (UPI) -- Scientists are trying to frighten sea lions away from the Columbia River's Bonneville Dam, to protect what is shaping up to be a weak salmon run this year.
The dam is 140 miles upriver from the Pacific Ocean, but dozens of sea lions have discovered that in the spring the fish ladders provide a ready supply of food, the Seattle Times reports.
This year, only 200 Chinook salmon have passed by the dam so far, compared to a 10-year average of 3,085 for the same date. No one is sure yet if the run is simply late getting underway or if something has happened to reduce the numbers of spawning salmon.
What scientists do know is that with so few salmon keeping the sea lions away is important. They are considering tactics tried 20 years ago to protect the steelhead run at the Ballard Locks in Seattle.
The newspaper says that noisemakers, sonar and possibly sea lion-proof gates protecting the fish ladders.
