SALEM, Ore.—The technical committee advising Columbia River fishery managers has released its forecast for the 2010 spring chinook run. If the fish show up as projected, the forecast of 470,000 spring chinook would be the largest return to the Columbia since 1938.
The forecasted run is up significantly from last year’s final run of 169,300 fish.
Because of challenges in forecasting the spring chinook returns in recent years, members of the Technical Advisory Committee (TAC) had to reconsider the model they have used in past years to predict the number of returning fish.
According to Stuart Ellis, current chair of the TAC and fisheries scientist of the Columbia River Inter-Tribal Fish Commission (CRITFC), committee members were leery of the record number of spring chinook “jacks” counted at Bonneville Dam in 2009. Jacks are immature, precocious males that return after just one or two years in the ocean.
In the past few years, forecasts relying heavily on jack counts from the previous season had overstated the actual return of adult fish by an average of 45 percent. An accurate preseason forecast is necessary to set commercial and recreational harvest levels that meet treaty obligations under U.S. v Oregon and conservation mandates to protect fish runs listed under the federal Endangered Species Act.
Ellis said this year the committee considered several additional models that took into account other factors such as ocean conditions.
“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 needed to account for that.”
“We’re still projecting a strong return for upriver spring chinook salmon next year, but we needed to temper last year’s jack return with other indicators of spring chinook abundance,” he added.
The seven models chosen by TAC generated a range of predicted run sizes from 366,000 to 528,000 adults. The committee members agreed on 470,000 as an average of the models. This forecast will now be used by the managers to develop preseason fishing plans.
The Technical Advisory Committee was established under the US v. Oregon and includes representatives from Oregon, Idaho and Washington fish and wildlife departments, the Columbia River Inter-Tribal Fish Commission (on behalf of the Nez Perce tribe, the Umatilla tribe, the Warm Springs tribe and the Yakama Nation,) the Shoshone-Bannock tribe, the National Marine Fisheries Commission and the U.S. Fish and Wildlife Service.