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NW Fishletter #392 April 1, 2019
 Fish Managers Predict Another Dismal Year For Columbia's Salmon, Steelhead Runs
Except for a huge surge of coho, fishery managers are predicting another poor year for anadromous fish returning to the Columbia and Snake rivers this year.
In all, 1.3 million salmon and steelhead are expected to come back to the Columbia Basin. That's nearly twice as many as last year's returns, which totaled 665,000 fish. But nearly all of the extra fish will be coho. If forecasts are right, some 726,000 coho will come back--up dramatically from the 147,300 coho that returned in 2018.
Fishery managers from Washington, Oregon and Idaho provided detailed information about last year's returns and this year's expectations for the Northwest Power and Conservation Council on March 12.
They also talked about why many of last year's predictions were significantly higher than the real numbers, and--while it's too early for forecasts--how other runs could begin to recover next year due to improving ocean conditions.
Dan Rawding, Columbia River policy and science coordinator for the Washington Department of Fish and Wildlife, said that while a lot of the runs last year were low, the 2018 summer steelhead return was the lowest since 1979--even worse than 2017 which was the second lowest.
And like some of the other runs, forecasters were off in their predictions--in this case, way off. Last spring, predictions put the summer steelhead returns at 190,350 fish. But only 100,483 came back, slightly better than half of what they expected.
WDFW predicts salmon and steelhead returns to the Columbia River will be similar to last year, but with significantly more coho. Credit: WDFW
This year, the forecast is for 126,950 summer steelhead returns, including 35,900 returning to the upper Columbia River; and 43,085 hatchery-origin plus 17,615 natural-origin returns to the Snake River.
Lance Hebdon, anadromous fishery manager for the Idaho Department of Fish and Game, said steelhead are particularly difficult to forecast because the majority spend only one year in the ocean and don't have any early-returning siblings to help forecasters, except for the rare steelhead that return to the ocean and come back for a second spawning. He said he's always "super cautious" about counting on steelhead forecasts because they are less reliable than many other stocks.
But other forecasts were also significantly higher than the actual returns, causing the U.S. v. Oregon Technical Advisory Committee to meet 28 times between April and October to receive updates on the run sizes and adjust fishing seasons when necessary to ensure enough fish would escape for hatchery needs and Endangered Species Act requirements.
Washington and Oregon closed the mainstem Columbia River and some of its tributaries to salmon and steelhead fishing due to the poor returns. Idaho closed its steelhead season under threat of a lawsuit, and reopened after an agreement was reached.
Responding to a Council question about the accuracy of their forecasts, Rawding said, "We're maybe as good as looking at the weather six months out. It's challenging, and we have limited information." He said budget cuts in 2011 resulted in dropping one of three annual ocean surveys that help them predict returns, and another potential cut could cause them to drop their May surveys.
Brian Burke, research scientist at NOAA's Northwest Fisheries Science Center, told the Council that the 2017 surveys resulted in the lowest catch of coho and Chinook in the 21 years that they've been conducting the survey. "It suggested we would see low returns of coho in 2018--which we did--and low returns of Chinook in 2019," which is the expectation, he said. But in the 2018 survey, they captured "tons" of coho--one reason for this year's forecast for a much better coho return; while Chinook captures were closer to average, contributing to early predictions for a more normal Chinook run next year. He noted that forecasters don't rely solely on the catch surveys for their forecasts.
Rawding added that while the coho run is "one of the bright spots" in this year's forecast, returns have been highly variable, and their prediction may be optimistic.
Other forecasts this year are for 99,300 spring Chinook above Bonneville Dam, down from 115,000 fish returning last year. That includes 9,100 hatchery and 2,100 wild upper Columbia River spring Chinook. About 35,900 summer Chinook should also return to the upper Columbia. Oregon is expecting 42,490 spring Chinook in the Willamette River, and Idaho's forecast is for 25,701 hatchery-origin and 6,130 natural-origin spring/summer Chinook.
Total Columbia River fall Chinook are forecast at 340,400 fish, including 261,100 above Bonneville Dam. Idaho is forecasting 10,016 hatchery-origin and 5,435 natural-origin fall Chinook.
Sockeye are also expected to be lower, with 94,400 sockeye expected to return to the Columbia River, compared to 210,915 last year. Only 86 hatchery-origin and 43 natural-origin sockeye are expected to return to the Snake River.
Forecasters look for a slight increase in wild winter steelhead coming back to the Columbia River, at 14,400 fish compared to 11,323 last year. And preliminary forecasts show 10,000 chum returning to the river below Bonneville Dam, the same number as 2018.
Rawding also told the Council that, while scientists aren't sure how much of a role ocean conditions play in the number of salmon and steelhead returning to the Columbia River, the 63 percent smolt survival rates for steelhead and spring Chinook from Lower Granite to Bonneville dam has only fluctuated slightly since 2006.
"This is just some weight of evidence that, I think, shows a lot of what we have is driven by the ocean," he said. -K.C. Mehaffey
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