Updated

Drought and record hot weather are producing lethal conditions for salmon and trout in rivers across the West.

A recent survey of the lower reaches of 54 rivers in Oregon, California and Washington by the conservation group Wild Fish Conservancy showed nearly three-quarters had temperatures higher than 70 degrees, considered potentially deadly for salmon and trout.

Low river flows from the record low winter snowpack, which normally feeds rivers through the summer, combined with record hot weather have created a "perfect storm" of bad conditions for salmon and trout, said U.S. Fish and Wildlife Service supervisory fisheries biologist Rich Johnson.

"It's unprecedented, I'd say," he said.

Oregon Climate Center Associate Director Kathie Dello says the entire West Coast saw record low snowpack last winter, leading to low rivers this summer. And all three states had record high temperatures for June, with Oregon breaking the record by 3 degrees. And the three-month outlook from the National Oceanic and Atmospheric Administration is for continued warmer and drier than normal weather.

The northwest could be looking at another dry winter, due to the ocean-warming condition known as El Nino, she added.

"This is the worst case scenario playing out right now, a warm winter and then a warm and dry summer," she said.

The Willamette River saw scores of dead salmon in June.

This week, state biologists examined about 50 dead sockeye salmon in the mouth of the Deschutes River. State fisheries biologist Rod French said they appeared to have been infected with a gill rot disease associated with warm water, and had probably left the warm waters of the Columbia River in search of cooler water.

In California, inland fisheries manager Roger Bloom says they are considering emergency fishing closures on several rivers so fish weakened by the warm water do not die from being played by an angler, even if they are released. They include the lower Merced, the American and the Klamath.

In Washington, two federal fish hatcheries in the Columbia Gorge released 6 million juvenile salmon two weeks early in the Columbia River, in hopes they would have a better chance of reaching the ocean before temperatures got even warmer, said Johnson.

"It's just a perfect storm of bad weather conditions for salmon," he said. "Pray for rain and snow."