<\/a>Dead, unspawned chum salmon line the banks of the Koyukuk River after a warm water event during Alaska’s unusually warm temperatures this July. (Courtesy photo | Stephanie Quinn-Davidson)<\/p><\/div>\n\t\t\t\t
Locals to the area said this same thing happened four or five years, ago, she said, but not to the scale it did this year.<\/p>\n\t\t\t\t
She attributes the deaths to heat stress.<\/p>\n\t\t\t\t
“We cut open the fish, looked for any size of disease, infections, parasites. … By all indications, these fish looked healthy,” she said. “They didn’t have any marks on them, or any sign of disease or stress otherwise. And the die off event coincides with the week of heat we had.”<\/p>\n\t\t\t\t
The total run was more than 1.4 million chum, she said, with some arriving before the warm weather event.<\/p>\n\t\t\t\t
“We definitely had chum salmon spawn,” she said. “And have chum salmon continue to make it to spawning grounds. There are salmon that made it through. Hopefully they’ll pass those genes on that allowed them to persist.”<\/p>\n\t\t\t\t
<\/a>A dead female chum salmon, her eggs unlaid, along the Koyukuk River this July. (Courtesy photo | Stephanie Quinn-Davidson)<\/p><\/div>\n\t\t\t\t
In the Kuskokwim, according to KYUK, there was a die-off of salmon having “heart attacks” due to the warmer than usual water along the ocean.<\/p>\n\t\t\t\t
In Norton Sound, large numbers of pink salmon were observed dead before spawning, according to KNOM.<\/p>\n\t\t\t\t
Conservation organization Cook Inletkeeper put out a release July 10 noting that on July 7, stream temperatures on the Deshka were 81.7 degrees Fahrenheit — more than five degrees above the previous highest-recorded temperature in that location, according to science director Sue Mauger. In the Deshka, the warm water created a thermal block that prevented the salmon from moving upstream.<\/p>\n\t\t\t\t
Mauger said she and others are in the middle of an intensive five-year temperature survey on the Deshka to figure out the location of the river’s cold waters, which could serve as refuges during climate change.<\/p>\n\t\t\t\t
“We have so many different types of systems (in Alaska) with different hydrologies,” Mauger said. “Some are fed by glaciers, some by snowpack, some by groundwater… and the joy of salmon is how diverse their life histories are, to capitalize on all that different habitat… but when you’re hitting temperatures in the 80 degrees, there’s no doubt fish are in high stress, and if they’re surviving they must be hitting cold water refugia.”<\/p>\n\t\t\t\t