[1] Nearly 500,000 Springers Predicted For Columbia Next Year
Acknowledging that their old way of doing things didn't seem to be working anymore, Columbia Basin harvest managers blended the results from seven different harvest models and have come up with 470,000 springers (to river mouth) as their preseason estimate of next year's upriver spring chinook run. That would be the largest run since 1938, when fish counters began tallying chinook at the brand new Bonneville Dam, surpassing the 440,000-fish return in 2001.
In 1995, fewer than 13,000 spring chinook made it back to the river.
They didn't exactly explain how they did it, but a Dec. 9 memo from the technical advisory committee that crunches the numbers in the US v. Oregon process said they have looked at non-linear relationships, ocean conditions and sibling relationships.
With conditions in the North Pacific likely switching into a colder, wetter phase [cool PDO], it has been tough for harvest managers to adjust, not to mention just keeping up with the coming and going of El Nino and La Nina conditions.
In 2008, ocean conditions were great for young salmon. Canadian scientists reported the coldest water in 50 years and plankton blooming from one side of the Gulf of Alaska to the other.
Just a few years earlier, in 2004, they reported the hottest water in 45 years.
However, with recent conditions that good, the harvest managers' years-long reliance on their simple linear relation between jacks, the precocious males that return a year earlier than the major component of the run, and the two-ocean fish that return later, has simply broken down.
Last year's spring chinook jack count was off the charts, around 80,000, which put it about 4 times higher than the last record count, which presaged the 2001 return of 440,000 springers. Some scientists have theorized that the good conditions may have boosted the one-ocean males' natural propensity to return.
The TAC memo noted that in four of the last six years, the actual return has been less than the forecast by an average 45 percent, though their 2007 return was pretty close to being on the money.
They say they looked at more than a dozen models to produce the estimated 2010 return and developed a range of 264,000 to 810,000 adults. Then they picked the seven models with the best hindcast performance and narrowed that range down between 366,000 to 528,000--470,000 is the average of all the models.
In 1995, only about 1,800 spring/summer chinook returned to the lower Snake, hatchery and wild.
They said that included 272,000 spring chinook heading for the lower Snake, with a wild ESA-protected component of 73,400 fish and more than 57,000 springers heading for the upper Columbia, with about 5,700 of them wild, and listed.
Upriver tribal fisheries and Idaho sporties have complained in recent years about getting shorted their share of the spring chinook, so the harvest managers say they have developed a more cautious management regime this year, that will allows a large cushion for error, to ensure the upper river fishers receive their fair share.
The harvests will be managed for a run size about 30 percent below the actual estimate, which will reduce harvest rates in the lower river fisheries compared to recent years.
The missed predictions in recent years led to higher non-treaty spring catches in the Columbia than treaty catches in 2008 and 2009. Treaty fishers will be allowed 14.3 percent of the spring run, non-treaty harvesters 2.7 percent. -Bill Rudolph
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More cautious management regime
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