Mature sockeye salmon (commonly called blueback, silver-side, Alaska red, or nerka) average three to seven pounds but can get as large as 15 pounds.
The dam was built and is managed by the United States Army Corps of Engineers.
Electrical power generated at Bonneville is distributed by the Bonneville Power Administration. Benjamin Bonneville, an early explorer credited with charting much of the Oregon Trail.
Adults average 22 pounds but many people frequently see 40 to 50 pound fish in the fish ladders at Bonneville Dam.
Chinook salmon spawn in the late summer and fall and die.
Steelhead are rainbow trout that migrate to the sea.
They average 10 pounds and can grow as large as 42 pounds.
Spawning occurs any time from late winter to late spring.
Juvenile steelhead can spend from one to three years in fresh water before migrating to the ocean.
After spending two to five years in the ocean, the chinook migrate up the Columbia River to the stream where they were born. The spring chinook run goes farthest upriver to spawn, the summer run doesn’t go as far, and most of the fall run stays in the lower Columbia tributaries though some stocks go into the Snake River and its tributaries.