Otters have made a remarkable recovery in UK rivers following pesticide bans, but their welfare faces ongoing threats from fishing gear entanglement, road mortality, and habitat degradation.
The otter welfare story in the UK is one of the conservation sector's great success stories, but recovery does not mean welfare challenges have been eliminated. Road mortality has replaced pesticide poisoning as the primary cause of death: otters following waterways encounter road crossings where they frequently choose to travel on the road surface rather than through undersized culverts, with fatal consequences. Otter-friendly underpasses and ledge systems that allow safe road crossing are highly effective but require coordinated infrastructure investment. Fishing gear entanglement affects otters in areas with intensive eel-pot and fyke net fishing - otters enter traps following fish and drown. Otter guards on traps are effective and increasingly required. The interaction between otter recovery and mink management creates welfare complexity: mink control to benefit water voles and ground-nesting birds reduces competition for otters, but the killing of mink raises its own welfare concerns. Habitat quality along rivers determines whether recovering otter populations can express full natural behaviour including territory establishment, breeding, and natural hunting.