July 18, 2024 — A persistent heat wave gripping parts of Washington state could spike temperatures as high as 105 degrees this week, prompting warnings from the National Weather Service to drink plenty of fluids, avoid the sun, and check up on relatives and neighbors.
There’s no mention of what to do, however, if you’re a salmon swimming upstream to spawn.
As air temperatures hit records in recent weeks, Native American and state fisheries experts and environmentalists are warning that water temperatures in the Columbia River Basin are similarly on the rise.
Those warming waters — in major tributaries like the Okanogan River and the Snake River — come at the same time as annual migrations of sockeye salmon from the Pacific Ocean, complicating a spawning ritual that spans hundreds of miles and is already peppered with human-made obstacles. Although salmon populations in the region have benefited from efforts to improve their spawning habitat, restore river flows and remove barriers from their travels, fisheries managers worry long periods of hot water could ruin it all in the years to come.
“Those water temperatures are warmer than ever this year,” said Tom Iverson, regional coordinator for the Yakama Nation Fisheries. “Literally, they’re almost too warm to swim in.”
That’s because the fish — including a record run of nearly 740,000 sockeye past the Bonneville Dam at border of Washington and Oregon as of Sunday, nearly 235 percent above the 10-year average — prefer a water temperature below 68 degrees.
The Okanogan River, which will be traversed by the majority of those fish during the final leg of their journey into British Columbia and a series of four chain lakes, has reached temperatures of nearly 83 degrees in recent days, according to U.S. Geological Survey data.
Reservoirs along the Lower Snake River, which are home to endangered Snake River sockeye, similarly crested to 69.53 degrees, according to the nonprofit Save Our Wild Salmon, which tracks water temperatures.