Otters have recovered dramatically in Britain since the 1970s. Their return signals improving river health and has positive welfare implications for multiple species including themselves.
Otter welfare is closely linked to river health. Clean water, fish availability, and undisturbed bankside vegetation determine whether otters can meet their energetic needs and rear cubs successfully. Road casualties represent a significant welfare problem: adult otters, especially males, travel long distances along river corridors and cross roads at multiple points. Otter underpasses and fencing to guide animals under bridges are effective interventions that reduce road deaths substantially. As a sentient mammal with complex social behaviour (females rear cubs for up to 14 months), otter welfare deserves consideration within river management and planning decisions.