Sea otters are a keystone species whose recovery along the Pacific Coast has had dramatic ecological effects. Their welfare is threatened by pollution, fishery entanglement, and ongoing population vulnerability.
Sea otter welfare is closely linked to ocean health. Oil spills cause acute welfare crises requiring intensive rehabilitation. Entanglement in fishing gear causes drowning. White shark predation, which has increased as shark populations recover, is now a leading mortality cause for southern sea otters. Domoic acid poisoning from harmful algal blooms — which are increasing with ocean warming — causes neurological damage. The welfare of sea otters is thus a proxy for broader ecosystem health, linking individual welfare to ocean pollution, climate change, and fishery management.