Sea otters are keystone predators in kelp forest ecosystems, and their welfare is linked to the health of the entire ecosystem they help maintain through predation on sea urchins.
Sea otter welfare has ecological dimensions beyond the individual. Each sea otter that maintains a territory in a kelp forest is an ecological engineer sustaining habitat for hundreds of other species. Oil spills affect sea otters catastrophically because their survival depends on fur insulation rather than blubber — oiled fur loses function within hours, causing hypothermia. Rehabilitation of oiled sea otters has been refined since the Exxon Valdez spill, achieving reasonable success rates. Toxoplasma exposure from domestic cat waste entering coastal water represents an ongoing mortality risk that can be reduced through cat litter disposal practices.