Heat Stress Monitoring
Arctic environments are warming at twice the rate of the rest of the globe with undeniable impacts on the fish, animal, plant, and human populations that reside in them. It is likely that rising ocean and freshwaters spawning temperatures caused by Arctic climate change causing of declines in Alaskan salmon sizes and populations numbers and changes in marine salmon habitats, including in Kuskokwim salmon populations.
Water temperatures in rivers throughout Alaska, including the Kuskokwim, are rising because of climate change. Western scientific researchers have found that water temperatures between 17ºC (62ºF) and 25ºC (77ºF) decrease salmon’s ability to swim upriver and reach their spawning grounds. Particularly high water temperatures induce heat stress in salmon, causing massive fish die-offs like those that happened in 2019 to chum salmon on the Kuskokwim and Yukon Rivers.
“For 60 plus years, my observation is that for the most part, the climate has really changed. The climate, the water temperature, the snow and ice conditions have really changed, especially in the last 20 years. That change has affected our way of life in Akiak with a lack of ice thickness, late freeze-ups and early break-ups, and lack of snow for most of the years in recent times. And that change may have affected the headwaters where the fish spawn, and also the ocean conditions out in the high seas. ”
KRITFC is monitoring water temperatures and heat stress in migrating king salmon to better understand the affects climate change will have on Kuskokwim salmon populations. In addition to recording daily water temperatures, the Takotna River weir crew takes non-lethal muscle samples of king salmon as they pass the weirs. These samples do not kill fish or harm their ability to spawn. The proteins in these flesh samples can later be analyzed for heat stress if high water temperature events are suspected.
Our heat stress and climate monitoring projects are relatively new, and we hope to continue using local observations and western science to track how Kuskokwim salmon populations are responding to our changing Arctic environments.