Rising River Temperatures Threaten Salmon in Pacific Northwest

Sockeye salmon in the Pacific Northwest have developed lesions and fungus because of abnormally high water temperatures in the Columbia River, according to a nonprofit organization that works to protect the river’s water quality.

The nonprofit, Columbia Riverkeeper, released video on Tuesday of injured salmon in the Little White Salmon River, a tributary of the Columbia. The temperature of the Columbia River currently exceeds 71 degrees Fahrenheit, the organization said in a news release, higher than the legal limit of 68 set by scientists to protect the salmon.

Salmon make an extraordinary migration, often hundreds of miles, from the inland rivers and lakes where they are born, out to sea, and back again to spawn. A network of longstanding dams in western states already makes the journey perilous. Now, with climate change worsening heat waves and droughts, scientists say the conditions look grim without intense intervention, which comes with its own risks.

“We’re in a salmon crisis,” Don Sampson, of the Northwest Tribal Salmon Alliance, said in a video detailing the stress upon salmon. “We’re seeing heat. Imagine the heat that we’re feeling. They’re feeling it 10 times worse in that river. They’re suffocating. They’re weakened.”

This isn’t the first time that marine life in the area has suffered. In 2015, more than 200,000 sockeye salmon were killed by hot water while swimming up the Columbia River, according to Reuters. And just weeks ago, abnormally warm temperatures in the Sacramento River in Northern California threatened the Chinook salmon population.

Wildlife experts say that similar disasters will become more common as dams and climate change continue to warm rivers or, worse, cause extinction, Columbia Riverkeeper said.

The Pacific Northwest has had a rough summer so far. A harsh heat wave in the region led to the deaths of hundreds of people, and wildfires have scorched large swaths of land. The combination of extraordinary heat and drought that hit the western United States in June has also killed hundreds of millions of marine animals and continues to threaten untold species in freshwater, scientists say.

Christopher Harley, a marine biologist at the University of British Columbia, said, “It just feels like one of those postapocalyptic movies.”

source: nytimes.com