Sea otters are a keystone species in kelp forest ecosystems. Their welfare is shaped by oil spills, entanglement, shark predation, and ongoing recovery from near-extinction through hunting.
Sea otter welfare reflects the consequences of a near-extinction event from which the species is still recovering. Limited genetic diversity from the population bottleneck increases susceptibility to disease. Individual welfare is dominated by nutritional demands: sea otters must eat constantly to maintain body temperature, and prey depletion from overfishing or disease creates nutritional stress that compromises immune function and reproductive success. Oil spills are catastrophic — otter fur loses its insulating properties when oiled, causing rapid hypothermia, and ingesting contaminated prey causes organ damage. Domoic acid events from warming-ocean-driven algal blooms cause neurological seizures that can be treated in rehabilitation if animals are found quickly. The Monterey Bay Aquarium's sea otter rescue and surrogate mothering programme is a model for welfare-conscious rehabilitation.