Salmon are showing up dead in record numbers across Western Alaska this summer, and scientists believe it is due to an unprecedented heat wave. Stephanie Quinn-Davidson, a scientist and director of the Yukon Inter-Tribal Fish Commission, led a group of fellow scientists to investigate along the Koyokuk River and counted “850 dead unspawned salmon on that expedition, although they estimated the total was likely four to 10 times larger.” The scientists saw no signs of disease or infections. These salmon, they believe, are dying off in record numbers due to the heat.
According to KTUU, many of the salmon found dead were carrying healthy eggs. Scientists know that rising water temperatures can enervate salmon too much to go through with spawning. It also makes moving oxygen through their bodies more difficult. Other researchers told NPR that salmon are known for being very “resilient” creatures. Their known resilience is what’s most disturbing about these die-offs.
Cook Inletkeeper’ science director Sue Mauger, who has been tracking “stream temperatures in non-glacial systems across the Cook Inlet watershed since 2002,” released a statement explaining that while they had never seen stream temperatures above 76 degrees Fahrenheit, they had clocked temperatures of 81.7 F in early July.
Mauger explains that these temperatures are clearly having a profound affect on the salmon, who normally wait until evenings for water temperatures to drop below 70 degrees Fahrenheit. During this summer’s heatwave, temperatures in the streams haven’t been dropping below 70 at night.