North American river otters are charismatic welfare indicators of aquatic ecosystem health, with population recovery from historic fur trade collapse now threatened by water quality degradation and pollution.
River otter welfare serves as a practical indicator of watershed health - their position as apex predators in aquatic food webs means contaminants concentrate in their bodies and their reproductive success reflects overall ecosystem quality. Otters experiencing sublethal contaminant burdens show reduced immune function, neurological impairment, and decreased reproductive success before population-level decline becomes apparent. The highly active, playful nature of otters makes confinement particularly welfare-impairing; animals kept in inadequate environments show stereotypic behaviors and reduced behavioral repertoire. Conservation approaches that improve water quality and protect riparian corridors benefit otter welfare directly.