Unlike some West Coast salmon stocks that have or are expected to nosedive, the Columbia River basin’s upriver spring chinook run trended upward this year.
Fish ladder counts at the Columbia River’s Bonneville Dam indicate fairly healthy numbers of adult upriver spring chinook headed toward hatcheries and tributary spawning grounds in 2008.
As of June 15, the official end of the spring chinook season on the Columbia, almost 152,000 adult chinook had been counted at the dam. That is slightly below the 10-year average from 1998-2007 of about 175,000 fish, but it is considerably better than the past three years, which ranged from 126,000 chinook in 2006 to only 81,000 in 2007.
Additionally, about 26,000 upriver spring chinook were caught this year in non-tribal sport and commercial fisheries carried out on the 146 miles of river below Bonneville.
The 2006 count halted a four-year trend in which the number of spawning upriver spring chinook had declined each year from a record high of 412,653 in 2001 to 97,397 in 2005.
Columbia River spring chinook are protected under the federal Endangered Species Act, as are Snake River spring/summer chinook. In a typical year, about 80 percent of the returning chinook adults consist of salmon that were raised in hatcheries; the remainder come from fish that spawned in the wild.
Counts at Bonneville Dam of spring chinook jacks—precocious, mostly male chinook salmon that return to spawn a year earlier than most of the female members of their cohort—are very high this year, over 22,000. That is more than twice the 10-year average.
Nearly as many upriver spring chinook jacks returned last year, slightly more than 20,000 were counted at Bonneville. Jacks are used as an indicator of the average strength of the next year’s adult returns.
Including adult chinook returning this year, jack counts in the last eight years have under predicted the following year’s adult returns four times and over predicted the return four times.
Recent improvements to the hydroelectric dams on the Snake and Columbia rivers are credited with increased survival of juvenile salmon heading downstream to the Pacific Ocean, according to a press release issued by four federal agencies involved in salmon recovery efforts. They include the U.S. Army Corps of Engineers and Bureau of Reclamation, which operate Columbia/Snake river basin dams, and the Bonneville Power Administration, which markets power generated in the system. The National Oceanic and Atmospheric Administration’s Fisheries Service is charged with protecting the 13 listed basin salmon and steelhead stocks.
Ocean conditions will always exercise a powerful influence over the salmon’s life cycle, the agencies say.
In that regard, initial surveys by biologists with show “very productive” ocean conditions north of Newport, Oregon.
That survey, completed late last month, showed, “These are very high numbers of juvenile salmon, some of the highest numbers we’ve ever seen,” according to John Ferguson, head of the Fish Ecology Division at NOAA’s Northwest Fisheries Science Service in Seattle.
Ferguson said there’s a strong correlation between high juvenile catches and good salmon returns in future years. The fish sampled offshore this year include coho that will return next year and spring chinook that will return in 2010.
A graph showing adult chinook counts at Bonneville Dam from 1939 through 2008 is available at salmonrecovery.gov.
