The otter has made a remarkable recovery in Britain following the banning of organochlorine pesticides, but individuals still face threats from road mortality, illegal persecution, and mink competition.
Otter recovery demonstrates the power of environmental legislation to produce welfare benefits at population scale. The ban on organochlorine pesticides, combined with water quality improvements and legal protection, removed the primary drivers of decline and allowed natural recovery. Individual otter welfare is now primarily threatened by road mortality, which can be mitigated through otter passes under bridges, and by illegal persecution associated with fishery protection. Maintaining clean, fish-rich rivers with undisturbed bank vegetation provides the resource base for otter welfare and population viability.