Huge Columbia River spring chinook run forecast

Fishery scientists forecast that some 470,000 spring chinook will return to the Columbia River next year, which would be the largest run since 1938.

That huge run size would be good news for sport, tribal and commercial fishermen who all place a high value on chinook, considered one of the finest-tasting salmon in North America.

But scientists who advise Columbia River fish mangers have struggled in recent years to come up with accurate run predictions, which have been based heavily on the numbers of immature jack males that return to the river each year.

Based on the jack model, the past several years of forecasts have overstated actual runs by about 45 percent, according to Stuart Ellis, a fishery scientist with the Columbia River Inter-Tribal Fish Commission.

The 2009 jack run was a record, but scientists were wary of using this jack return to project 2010.

"The number of jacks that returned in 2009 was four times greater than anything we've seen before, which made the number a statistical anomaly," Ellis said. "At the same time, we know the environment for young salmon appears to be changing and we need to account for that."

The new forecast is based on an expanded set of models. Accurate forecasts are necessary to set harvest at levels that meet treaty obligations and conservation requirements under the federal Endangered Species Act.