Eurasian otter populations have recovered substantially in the UK following bans on organochlorine pesticides, but water quality pollution and road mortality continue to cause significant individual welfare harm.
Individual otter welfare is directly affected by water quality — polluted rivers with depleted fish populations force otters to travel farther for food, expending more energy and increasing road crossing frequency. Road mortality on bridges causes traumatic death and orphans dependent cubs. Otters caught in eel traps and fish pens drown — an acute welfare concern in areas where these are still deployed. Water quality improvement — reducing agricultural run-off, treating pharmaceutical pollutants, and maintaining riparian vegetation — directly improves otter welfare by restoring food abundance and reducing the need for extensive territory traversal. Otter ledges under bridges and culverts that allow otters to avoid road crossings are a proven and cost-effective welfare intervention.