Cold-water refugia where groundwater upwellings maintain low temperatures are critical welfare resources for salmon during increasingly warm summers.
Salmon climate refugia are welfare lifelines during thermal stress events. Salmon congregating at a cold-water upwelling during a heat wave are using a behavioral thermoregulation strategy — seeking the one place in the watershed where temperatures allow physiological recovery. Protection of these sites from physical modification, reduced groundwater extraction, and vegetation management to enhance shading are all direct welfare interventions. The identification and protection of refugia sites is increasingly urgent as the frequency and intensity of thermal stress events increases with climate change.