Scientists were shocked: large numbers of salmon died in Alaska due to extreme heat

This relates to different species of salmon from Alaska, including Sockeye, Chum, and Pink Salmon. Scientists who navigated the Koyukuk River counted 850 dead salmon there, but estimated that the total number of deaths was four to 10 times that number.

There are no parasites or infections

Investigations into parasites or infections in salmon have yielded nothing. The fish were unharmed and carrying healthy eggs. According to scientists, the fish must have died due to the high temperature.

In July, temperatures exceeding 32 degrees Celsius were measured in Alaska. The water temperature was also over 27 degrees at that time. This high temperature has never been measured in more than 100 years as America's northernmost state has been keeping its statistics.

1.4 million salmon

Due to the heat, the fish do not get enough oxygen and do not have the energy to lay healthy eggs that were already in the fish's stomachs.

According to lead researcher Stephanie Quinn-Davidson, more than 1.4 million salmon passed through the recently studied river. “Some got there before the warm weather,” Quinn Davidson told Alaska's Juneau Empire newspaper.

“There are still chum salmon arriving at the spawning areas,” Quinn Davidson continues. “We hope that these salmon passed on the genes that allowed them to survive in the heat.”