October 16, 2025 — Fisheries researchers have concluded that Chinook salmon in shallow streams in western Canada will be impacted in the coming years by the frequency, duration, and intensity of heatwaves.
When salmonids encounter high water temperatures, it may increase their susceptibility to infectious disease, according to the research published by the University of Waterloo, in Ontario, Canada, and Yellow Island Aquaculture Ltd. on Quadra Island, British Columbia, in the online journal Elsevier.
Their research has found that the disproportionate changes in temperature for three consecutive days or longer have risen in recent years and are expected to continue increasing globally in the coming decades.
Heatwaves result in several downstream consequences, including increased water temperatures in shallow streams and rivers, and there is a strong positive correlation between daily water and air temperature. Shallow rivers are particularly susceptible to temperature fluctuations. For every 1 °C increase in air temperature, stream temperature correspondingly rises approximately 0.4–0.6°C.