Eurasian otters and their North American counterparts face habitat and pollution threats — their welfare and conservation are inseparably linked.
Otter welfare is shaped predominantly by water quality and waterway connectivity. Pollution reduces prey availability and bioaccumulates in otter tissue through the food chain — organochlorine pesticides that caused otter population collapse across Europe in the mid-20th century did so by causing reproductive failure and individual poisoning over years of chronic exposure. Road mortality causes acute traumatic death at waterway crossings where otters leave water to move between river sections. Otter tunnels and underpasses at road-waterway intersections dramatically reduce this mortality and the suffering it causes, making infrastructure investment one of the most direct welfare interventions available for this species.