Sea otters were hunted nearly to extinction for their fur and have made a partial recovery. Their welfare depends on clean kelp forest habitat and protection from oil spills, pollution, and disease.
Sea otter recovery is a conservation success story that also reflects the welfare of individual animals. Oil spills are particularly devastating to otters because their fur provides all their thermal insulation — contaminated otters die of hypothermia unless cleaned, a prolonged and distressing process. Domoic acid poisoning from toxic algal blooms, amplified by coastal nutrient runoff, causes neurological symptoms and seizures in otters before death. The ongoing recovery of sea otter populations has created ecosystem benefits — restored kelp forests, greater marine biodiversity — that serve as a model of how conservation investment improves welfare for entire ecological communities. Protecting water quality and preventing oil spills are direct welfare interventions for sea otters.