Read the full story at Phys.org.
Billions of dollars have been spent over the last four decades to save Snake River salmon by restoring streams, relocating sea lions and other predators, building hatcheries and helping fish get past dams. But those efforts increasingly look futile.
As heat waves become more common and river temperatures rise, few fish complete the treacherous journey from the Pacific Ocean through eight dams to their spawning grounds in southern Idaho—a 900-mile trip up the Columbia and Snake rivers and their tributaries.
Hoping to avert disaster amid record July heat, the National Oceanic and Atmospheric Administration authorized an emergency plan to help the sockeye skip the final 300 miles of their migration.