Eurasian otters (Lutra lutra) have recovered significantly across Europe following bans on organochlorine pesticides and improvements in river water quality — a conservation success with direct welfare implications.
Otters that died during the pesticide era experienced neurological damage, reproductive failure, and death from accumulation of organochlorine compounds in their fatty tissues. The recovery of otter populations following pesticide bans demonstrates the direct welfare and conservation benefit of environmental protection legislation. Contemporary otter welfare threats include road mortality — otters killed on roads near culverts and bridges that are easier to cross on land than through water — and habitat fragmentation that forces long overland movements between water bodies. Each road-killed otter that had established territory, may have been breeding, and had a life expectancy of years represents a welfare loss prevented by simple infrastructure solutions (otter passes under bridges) that are cost-effective and well-established.