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Low 2012 Jack Counts has Preseason Forecast for 2013
Spring Chinook Return at Lowest in 6 Years

by Staff
Columbia Basin Bulletin, December 7, 2012

Adult upriver spring chinook returns in 2013 are likely to dip a bit from last year, according to preseason forecasts produced this week by the Technical Advisory Committee.

The forecast for the upriver spring chinook return to the mouth of the Columbia next year is 141,400 as compared to an actual return of 203,100 last year. TAC is made up of experts representing federal, state and tribal fish management entities.

Upriver spring chinook represent an aggregate of populations, and includes all spring chinook destined for areas upstream of Bonneville Dam, including Snake River spring/summer fish.

Such a return would be the lowest since 2007, when only 86,000 spring chinook returned.

The age-based 2013 forecast hinges on what was a relatively poor return of 3-year-old "jack" upriver spring chinook salmon this year. The count at Bonneville, 10,337, was the lowest since 2006. The total jack count (Jan. 1 through June 15) in 2009 was more than 81,000. The jacks are precocious males that return to freshwater to spawn after only one year in the ocean.

The strength of the 3-year-old return one year is considered a sign of the strength of the 4-year-old class the next year.

Four-year-old upriver spring chinook salmon typically dominate any year's return and this year is no different. The TAC forecast includes 115,000 4 year olds, which is a relatively low total for recent times, according to Stuart Ellis, a Columbia River Inter-Tribal Fisheries Commission biologist and member of TAC.

The new forecast is for a return of 25,700 5-year-olds next year, which is closer to the recent average, Ellis said. The prediction for 6-year-old upriver spring chinook returns to the mouth of the Columbia is only 300 fish.

"We have not been seeing many age 6 fish" in recent years, Ellis said.

The relationship between jacks and adult fish in the last few years has differed from historic patterns so TAC in 2009 began to examine modifications and alternatives to its forecast methodology. Since then the panel has employed a variety of statistical models, including those that input ocean condition variables.

The end product is for the most part an average of the individual model outputs. In some years the range of model forecasts has been wide. This year the models were largely in agreement, ranging from a low upriver spring chinook 4-year-old forecast of 100,000 and a high forecast of 145,000.

The TAC forecast for 2013 Upper Columbia summer chinook return to the mouth of the Columbia is 73,500 adult fish, which would be slightly above last year's actual return of 58,300. Such a return would be the second highest since 2003. Upper Columbia summer chinook are fish destined for areas upstream of the mid-Columbia's Priest Rapids Dam.

The upriver spring chinook and Upper Columbia forecasts released this week are the first of many. Still to come are more stock-specific forecasts, such as for Snake River spring/summer chinook and Upper Columbia spring chinook, and for sockeye salmon. Tributary forecasts will also become available later.

Steelhead, fall chinook and coho forecasts will be developed after the New Year.

Low 2012 Jack Counts has Preseason Forecast for 2013 Spring Chinook Return at Lowest in 6 Years
Columbia Basin Bulletin, December 7, 2012

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