Alaska has been in the throes of an unprecedented heat wave this summer, and the heat stress is killing salmon in large numbers.  Scientists have observed die-offs of several varieties of Alaskan salmon, including sockeye, chum and pink salmon.

The water temperatures have breaking records at the same time as the air temperatures, according to Sue Mauger, the science director for the Cook Inletkeeper.

“Physiologically, the fish can’t get oxygen moving through their bellies,” Mauger said. In other places in the state, the salmon “didn’t have the energy to spawn and died with healthy eggs in their bellies.”

 

https://www.cnn.com/2019/08/16/us/alaska-salmon-hot-water-trnd/index.html