Bethel, Alaska (AP) - Record-high temperatures in Alaska are believed to be the cause of salmon deaths in western Alaska.
Water temperatures near Bethel broke into the low 70s earlier this week, the highest river temperature ever recorded there, Bethel-based KYUK reported. Those conditions were part of a heatwave that swept the state.
"Essentially, what could happen is salmon metabolism speeds up to the point that they're having heart attacks and going belly up and floating downriver," said state Department of Fish and Game biologist Ben Gray.
Residents along the lower Kuskokwim River have reported dead salmon floating downstream between the villages of Tuntutuliak and Akiak.
Gray and his colleagues counted about 20 dead salmon when they boated between Bethel and Akiak to check the area out.
The warm temperatures also are suspected to be the cause of parasites infesting salmon in the river, with the warm water coming from the ocean.
In Kuskokwim Bay, temperatures have measured as much as 12 degrees above average throughout the summer, with tides pulling warm water into the lower river.
"And that water is pushing upriver," Gray said. "And it's mixing, and we're having a profile in the water right now where it's a solid 68 to 70 degrees (21 Celsius) all the way through."
In Norton Sound, residents have reported large numbers of dead pink salmon that had not yet spawn.