BONNEVILLE DAM -- Record numbers of sockeye salmon are returning to the Northwest's Columbia Basin, with more than 400,000 expected this year.
Since Bonneville Dam outside Portland was built in 1938, there have been plenty of times there weren't 38,000 sockeye salmon swimming over the fish ladders in a whole year. But on Tuesday that many passed the Columbia River dam in a single day. Another 41,000 swam over the dam on Wednesday -- a rate of nearly 30 a minute.
Sockeye swim farther to spawn than any other species of salmon in the Northwest, and cross nine dams to reach spawning grounds in in northern Washington and Canada.
Biologists credit habitat improvements in the Okanagan Basin of northern Washington and Canada, improved dam operations, and favorable ocean conditions for the numbers.