Research indicates record salmon returns in Columbia River basin

By Staff
Hydro World

Conservation efforts in the Pacific Northwest are paying off as record numbers of sockeye salmon are returning to the Columbia River.

So far this year, nearly 300,000 Okanagan sockeye salmon have swum up the fish ladder at Bonneville Lock and Dam, while chinook, coho, chums, pinks and steelhead are also expected to return in large numbers. Records show fewer than 9,000 of the above named species returned to the Columbia Basin in 1995, and the Okanagan sockeye – a type particularly difficult to rear in hatcheries – were quickly dwindling.

Although some of the fish population’s increase can be attributed to natural factors such as favorable ocean conditions, biologists say habitat improvements made at many hydroelectric facilities have also been a significant ingredient in the fish resurgence.

Not only have utilities and hydropower plant owners begun providing more natural spawning areas in their facilities’ designs, but also they have developed flow schedules that give roe a better chance of surviving.

The U.S. Army Corps of Engineers, which owns and operates the 1,076.6-MW Bonneville project, currently is undertaking fish ladder improvements to address lamprey passage at the dam.