Sea otters depend on abundant benthic invertebrate prey whose availability is increasingly threatened by warming ocean temperatures, ocean acidification, and the ecological cascades these changes trigger in coastal ecosystems.
The energetic demands of sea otters make them acutely vulnerable to prey availability fluctuations caused by climate change and ecosystem disruption. Without adequate daily food intake, sea otters lose condition rapidly and face starvation stress. Marine heatwaves associated with climate change have caused mass mortality events in key prey species including sea urchins and bivalves, creating foraging deficits that are especially harmful for nursing females with pups. The collapse of the Sunflower Sea Star from sea star wasting disease, itself linked to warming waters, removed a major predator of sea urchins, leading to urchin barrens that replace productive kelp forests. This cascading ecological change reduces prey availability for sea otters in affected regions and demonstrates how climate-driven ecosystem disruption translates into individual animal welfare harms across trophic levels.