Federal hatchery managers are keeping an eye on warming river water as temperatures continue to rise throughout the Pacific Northwest.
The U.S. Fish and Wildlife Service this week released 6 million fish from the Little White Salmon and Willard National Fish hatcheries about one week ahead of schedule. Both hatcheries feed into the Columbia River near White Salmon, Washington.
Miel Corbett, a spokeswoman with the service, said changes in water temperature can stress out these upriver bright fall chinook salmon. But that's not the only problem warming waters can have for fish.
“Higher water temperatures mean that there could be an increased likelihood of disease,” Corbett said.
That’s why the U.S. Fish and Wildlife Service decided to release fish now: to avoid some of those problems as much as possible.
The service said temperatures in the Columbia River were at about 70 degrees right now. Salmon usually prefer temperatures around 68 degrees.
The service also released more than 200,000 steelhead on the Olympic Peninsula one month ahead of schedule.
River temperatures are also warming elsewhere in the Northwest. Hatchery managers have seen about 200 fish die off in the Portland Harbor area.