Salmon Runs Above Averageby Staff
BPA Journal, January 2006
As 2005 comes to an end, fish counts at Bonneville Dam are moderately above average for adult salmon returns in the Columbia Basin with just over 569,000 chinook and 315,000 steelhead passing the dam by mid-December. Coho returns (83,000) are also above average and sockeye returns (73,000) are even stronger.
The numbers were reported by the NOAA Fisheries Service. While spring chinook counts were lower than average in 2005, summer and fall chinook adult returns were above average. Government biologists said that the numbers reflect improvements to salmon habitat and to hydropower dams on the Columbia and Snake rivers, which helped offset slowly declining ocean conditions that may have dampened adult returns.
Because ocean conditions strongly influence the rate of adult returns, government biologists say that the timing of when juvenile salmon arrive in the seawater environment may be crucial. Salmon returns depend on ocean Conclusions from studies of Northwest salmon migrations strongly point to ocean conditions as a major factor in the numbers of adult salmon that return to spawn. Two scientists from British Columbia told the Pacific Northwest Power and Conservation Council that smolt survival in the Columbia River system seemed reasonably high.
Dr. David Welch said, "The problem is the deficit of adults coming back." Welch went on to say, "There's a tremendous amount of effort being put into how [the Columbia and Snake river stocks] get past the dams, but the mortalities that are happening in-river are insufficient to explain the overall decline" in the percentage of adults that return.
BPA funded the research following the emergency power operations of 2000-01.
learn more on topics covered in the film
see the video
read the script
learn the songs