Salmon forecast: sockeye up, chinook down

December 18, 2016

The forecasted return of adult spring and summer chinook salmon to the Columbia River basin in 2017 will be lower than initial estimates made last year in December, but the estimate of sockeye salmon is nearly twice the size of last year’s estimate, according to an early forecast of the runs released this week by the U.S. v Oregon Technical Advisory Committee. TAC estimated the total run of spring/summer chinook salmon for 2017 at 160,400 fish. Last year’s early forecast was 188,800, but the actual return to Bonneville Dam was higher with 137,215 spring chinook and 119,591 summer chinook. A forecast by the Oregon Department of Fish and Wildlife this week estimates a run of spring chinook salmon into the Willamette River of 40,200, far lower than last year’s forecast of 70,100 fish, but closer to the actual 2016 tally of 49,800 spring chinook. Some 198,500 sockeye will enter the Columbia River, according to TAC. That is nearly double last year’s forecast of 101,600 fish, but far below the actual and surprising count of 342,498 sockeye that passed Bonneville Dam. The fall chinook forecast is not yet available. TAC, made up of federal, state and tribal representatives, was formed by the parties to the U.S. v. Oregon court case. According to an interview last year with Stuart Ellis, harvest management biologist with the Columbia River Inter-Tribal Fish Commission, the forecasts are largely age-based and the number of jack salmon from the current year also aid in the following year’s forecast. “We reconstruct the runs based on age data collected at Bonneville, in the fisheries, and in escapement areas,” Ellis said in December 2015. “One of the most common methods is to do statistical regressions between the ages. Sometimes we use ratios. We look at relationships between various time periods too.” TAC also tries to incorporate environmental information, such as ocean conditions, into its forecasts, he said. Jacks have always served as a pretty good index of the survival of a certain brood to date. In a way, Ellis said, jacks can be looked at as a type of ocean indicator. “For spring chinook, jacks play a big part in our assessment of the 4-year old return which is normally the biggest age class in any year.” Of the 160,400 spring/summer chinook forecast for 2017, 19,300 of the fish are upper Columbia River spring chinook with 3,700 naturally produced or wild fish. Some 95,800 (15,200 natural origin) will be destined for the Snake River and the rest are Mid-Columbia River stocks. The total upper Columbia River summer chinook run is anticipated to be 63,100 fish, according to information from TAC provided this week by Ellis. In addition to the Willamette forecast of 40,200 spring chinook, 17,100 fish will head up the Cowlitz River, 3,100 into the Kalama River and 700 into the Lewis River, all rivers in Washington State. Of the 198,500 sockeye, just 1,400 will go to the Snake River, 54,200 to the Wenatchee River, 137,900 to the Okanagan River, 4,000 to the Yakima River and 1,000 to the Deschutes River. This year (2016), the actual count of spring chinook salmon at Bonneville Dam was 137,215 adult fish and 11,145 jacks, far below the 2015 count of 220,480 adults and 13,314 jacks. The 10-year average is 146,704 adults and 24,884 jacks. The actual count this year for summer chinook at Bonneville was 119,591 fish and 10,834 jacks, also far below the 2015 count of 161,735 adults and 17,730 jacks. The 10-year average is 95,523 adults and 21,451 jacks. Again, the actual count for sockeye at Bonneville in 2016 was 342,498 fish (more than three times the 2016 early forecast of 101,600 fish). The actual count at Bonneville in 2015 was 510,706 and the 10-year average is 285,072. The count in 2016 at Lower Granite Dam, the upper of four lower Snake River dams, was 816 (Lower Monumental was 1,024). The 2015 count at Lower Granite count was a depressing 440 (one of the warmest years on record) and the 10-year average is 983. The count at Lower Monumental in 2015 was 888 and the 10-year average is 983.