Major Passage problems
Columbia River Salmon and Steelhead Symposium
American Fisheries Society
Since 1968, four new dams have been completed in the Snake and Columbia Rivers.These dams have had a drastic effect on the survival of both steelhead trout and Chinook salmonstocks in the upper Snake River. As more dams are constructed the survival of juvenilesalmonids declined with a low of less than 10% being recorded in 1973. The major losses of thejuvenile stocks are not attributed to the turbines, supersaturation of the water with nitrogen, thedelay in migration caused by impoundments and an increase in predation.