BEND, Ore. (AP) — Above-average temperatures on the Lower Deschutes this summer have steelhead anglers concerned about the quality of fishing on the river and the overall health of its hard-fighting, oceangoing rainbow trout.
But biologists say the Lower Deschutes is cooling down and that this year's steelhead run could be even bigger than last year's enormous run of 600,000 steelhead returning to the Columbia River.
The Oregon Department of Fish and Wildlife does not make specific forecasts for the Deschutes, but steelhead must pass through Bonneville Dam and The Dalles Dam on the Columbia before they can turn south into the Deschutes.
According to Rod French, an ODFW biologist based in The Dalles, some 450,000 steelhead are expected to pass through Bonneville Dam this year, well above the average. Last year's prediction was 350,000 and the total turned out to be 600,000.
"Early numbers are higher than last year," French said. "It looks to be another very strong run. Right now, there's more fish above The Dalles Dam than last year."
With the activation of a new fish transfer facility in April at the Round Butte Dam on Lake Billy Chinook, temperatures on portions of the Lower Deschutes River last month were up 2 to 5 degrees over the historical average.
The Round Butte project is part of an effort to return river conditions to what they were before the dam was built in 1964, including elevated water temperatures in spring and early summer and cooler temperatures in late summer and fall.
Those cooler temperatures are beginning to show, and Portland General Electric (PGE) earlier this month increased the amount of cooler water released from Lake Billy Chinook into the Lower Deschutes.
"In July there was some concern (about fish health)," French said. "But modifications have been made, and more cooler water is coming out of the bottom (of Lake Billy Chinook). The temperatures are now identical to what they were last year at this time, if not cooler. And the trend would be from here on for it to be cooler than last year."
Those cooler temperatures in the Lower Deschutes are critical for steelhead runs. If the Deschutes is warmer than the Columbia, hatchery steelhead generally will not make the turn south into the Deschutes and toward Central Oregon.
French said steelhead fishing has been "quite good" this summer from the mouth of the Deschutes 35 miles south to Beavertail Campground, with the peak of the run set to arrive in mid-September.
"The fishing is really starting to crank up right now, but it's been steady since July," French said.
This year's fish could be bigger, too. French said many of the steelhead appear to be two-salt fish steelhead that have spent two years in the Pacific Ocean and weigh 6 to 12 pounds. The 2009 run was dominated by one-salt fish, which range from 4 to 6 pounds.
French added that 2010 could be another banner year in the Lower Deschutes for fall chinook salmon as well. The run prediction for fall chinook in the Columbia is 650,000 fish, compared with 429,000 returning chinook last fall.
The fall chinook season began Aug. 1 on the Lower Deschutes, where fishing for chinook is allowed from the mouth upstream to Sherars Falls.
Steelhead anglers can fish from the mouth all the way to Round Butte Dam.
A project of PGE and the Confederated Tribes of Warm Springs, the $110 million fish and water intake at Round Butte Dam was designed to restore historical populations of chinook and steelhead that once migrated up the Middle Deschutes, Crooked and Metolius rivers before the dam was built. (About 110,000 fish have passed through the fish intake since March, according to PGE.)
Until the fish passage was activated, all water that passed downstream from the dam had been drawn from the bottom of Lake Billy Chinook, between 220 and 260 feet below the surface.
With the completion of the fish transfer facility where migratory fish headed downstream are captured and trucked around the dam a second water intake was added, drawing in water from the surface down to about 45 feet deep.
The two water intakes allow PGE to adjust the temperature of the water it sends downstream by blending warmer water from the shallows with cooler water from the bottom of the lake.
Earlier this month, the Oregon Department of Environmental Quality and the Warm Springs Tribal Water Control Board instructed PGE to increase the amount of cooler water released into the Lower Deschutes from 30 percent to 40 percent deep (cooler) water.
"We expect to keep it at 40 percent all the way through October," Don Ratliff, senior biologist for PGE, said this week. "We want to meet the state and tribal standards, and make the project invisible.
"What anglers will start to see is the benefit of water temperature management, and the cooling of the Lower Deschutes in late August and September like what it used to be before the dam."
While water temperatures on the Lower Deschutes appear to be cooling now, the ODFW is asking anglers to take the following precautions when water temperatures are above 70 degrees and added stress to the fish could be a concern:
- Fish during the cooler times of the day, usually mornings and evenings.
- Use barbless hooks, and play and land fish quickly.
- Release wild fish quickly.
Copyright 2010 The Associated Press.