Fish Fryby Eric Barker
The Lewiston Tribune, August (?), 2000
Hot Weather is Murder on Delicate Stocks of Salmon and Steelhead
No rain, an early spring and high temperatures could be bad news for Snake River salmon and steelhead.
Biologists expect a good return of adult steelhead above Lower Granite Dam on the Snake
River this year but high water temperatures could negate the positive effects of improved ocean conditions and good out-migration conditions in previous years.
"We are expecting a pretty good run but the water conditions are deteriorating rapidly," said Kent Ball, a steelhead specialist with the Idaho Department of Fish and Game at Salmon.
"It looks like we should have a really good run if we can get them up the river." Ball said last year's return of 8,800 hatchery B-run steelhead to the lower Clearwater River should be doubled this year based on preseason projections. Biologist are expecting more than 254,000 steelhead to pass Bonneville Dam on the Columbia River.
Water temperatures in the Columbia and Snake rivers are hovering between 70 and 72 degrees. At Lower Granite Dam, temperatures reached as high as 74 degrees on Sunday before dropping a couple degrees. River flows at the dam have averaged about 27,000 cubic feet per second in recent days. That is well below normal and it includes about 12,000 cfs of 48-degree water from Dworshak Reservoir.
But the Dworshak water is scheduled to quit flowing during the last week of August or first week of September when the reservoir reaches a mark of 80 feet below full pool. "It's almost inevitable that water temperatures will get up to 73 or 74 degrees and that will shut them (steelhead) down," said Ball.
When water temperatures climb that high, migrating adults seek the cool water of Columbia River tributaries. It's the same effect that can mean great fishing for A-run steelhead in the Clearwater River when fish seek cooler water there before heading up the Snake, Salmon and Grand Ronde rivers.
However, when fish stall out in the Columbia River for prolonged periods of time, many never make it to the Snake.
"When we hold them up, we lose a bunch of them," said Ball.
Adults in warmer water are more prone to suffer infections from any injuries they may receive during migration.
There is little relief in sight, according to Kyle Martin, a hydrologist and meteorologist with the Columbia River Intertribal Fish Commission.
"We are essentially looking for more of the same, bone-dry conditions and warmer-than- normal temperatures extending through October."
Those conditions are exactly what the commission, the Nez Perce Tribe and the state of Idaho feared when they tried to persuade the federal government to save some of Dworshak's cool water for September to help adult steelhead and late-migrating juvenile fall chinook.
"The Clearwater is going to heat up by Labor Day," said Martin. "When that happens the heating effect is going to make the lower Granite pool and the Clearwater an absolute sauna for fish."
The National Marine Fisheries Service decided the water was needed in July and August when the majority of juvenile fall chinook are migrating.
Steve Pettit, a fisheries biologist for the Idaho Department of Fish and Game at Lewiston, said there already have been reports of juvenile fish suffering heat stress at Lower Monumental Dam on the Snake River and McNary Dam on the Columbia River. He said fish managers are considering suspending all handling of juvenile fish at the dams and bypassing as many as possible.
"All we can do is sit back and hope the weather will change and we will get an early cool fall or we are going to be set out for a pretty devastating temperature impact."
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