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Ecology and salmon related articles

Feds Seek Ways to Avoid
Another Columbia Basin Fish Kill

by Keith Ridler
Idaho Statesman, March 6, 2016

Lower Granite Dam impounds Snake River waters nearly forty miles to the Idaho border. BOISE, IDAHO -- Northwest fisheries managers are creating a response plan should there be a return of warm water conditions that scientists say was a main factor in killing 90 percent of the adult sockeye salmon returning to the Columbia Basin last summer.

The report expected this spring will also suggest ways to cool water temperatures that became lethal in June and July for most of the 510,000 adult sockeye that entered the Columbia River to spawn.

But Ritchie Graves with the National Oceanic and Atmospheric Administration said options are limited when an extended heat wave coincides with low flows in rivers as in 2015, pushing water temperatures above 70 degrees.

"If the tributaries are all pouring hot water into the main system, then the system is going to be hot," he said, noting the high temperatures in the basin last year had not occurred since at least the 1950s.

In a separate action, a coalition of environmental groups in a February letter to the U.S. Army Corps of Engineers said the agency needs to implement emergency measures or risk violating the Endangered Species Act should more massive fish kills occur. Thirteen species of salmon and steelhead are listed as endangered or threatened in the Columbia River basin.

Kevin Lewis of Idaho Rivers United said the Clearwater and Salmon rivers supply cold water to the system that's negated by the four dams on the lower Snake River where the water warms. He said removing those dams would cool the Columbia.

"It's unacceptable for myself and many others that hundreds of thousands of our fish our dying in the Columbia and Snake and the only response from the federal government is a shrug of the shoulders," he said.

Graves said early suggestions in the plan include putting in new temperature sensors that update faster and would give managers more advance warning about warm water conditions.

Last summer, cold water releases from Dworshak Dam was used to cool the Snake River, and Graves said examining how that could be done more effectively will be considered.

Some physical changes are also being made, including drawing cooler water from deeper in the pool behind Lower Granite Dam this year to be used in the dam's fish ladder. Managers say fish previously halted migrating due to warm water in the ladder.

Another aspect would be to set criteria for when emergency actions would go into effect, such as emergency captures of Snake River sockeye.

Graves said the basin's sockeye salmon were the hardest hit by last year's warm water conditions, mainly because of the June-July timing of the migration run.

The Columbia basin at one time had up to 10 runs of lake-spawning sockeye, but now has three. Of last year's 510,000 fish that entered the Columbia River, about 400,000 were headed for the Okanogan River and Okanagan Lake in British Columbia. Graves said about 5 percent of them made it.

More than 100,000 were headed for the Wenatchee River and Lake Wenatchee in Washington state. About 10 to 15 percent of those fish arrived.

Counts at Bonneville Dam on the Columbia River showed 4,000 endangered Snake River sockeye salmon passed through on their 900-mile river journey to high-elevation Sawtooth basin lakes in central Idaho. Managers counted 55 that arrived.

When the severity of the fish kill became apparent, workers set up a trap at Lower Granite Dam and captured another 35 Snake River sockeye. Of the 90 total fish, 85 went to a hatchery for artificial spawning. Five were released into Pettit Lake to spawn naturally as part of efforts to rebuild a wild run.

Idaho managers say a captive breeding program for Snake River sockeye means the fish kill in 2015 is not a disaster for efforts to rebuild the run.

"What it did do, though, is set us back a little bit with the overall goal of slowly moving them more and more toward natural reproduction," said Russ Kiefer of the Idaho Department of Fish and Game.

He said workers released about 500 hatchery-raised adult fish into Redfish Lake last fall, and about 100 into Pettit Lake.

Graves said salmon and steelhead have life histories that spread the risk so one bad year won't wipe out an entire population. The big question for biologists now, he said, is how often warm-water events like last year are likely to occur.

"Once in 10 or 20 years, it's a setback," he said. "If it's a one in two- or three-year event, it's going to be a problem."

Related Pages:
90 Percent of Snake River Sockeye Died Before Reaching First Snake River Dam by Courtney Flatt, NW Public Radio, 12/7/15

Keith Ridler
Feds Seek Ways to Avoid Another Columbia Basin Fish Kill
Idaho Statesman, March 6, 2016

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