Eurasian otters have recovered from near-extinction in Britain; their welfare as indicator species reflects the health of freshwater ecosystems they depend on.
Otter recovery is one of Britain's great wildlife conservation successes - a direct result of regulatory action on pollutants. However, individual otters are still killed in high numbers on roads as populations expand and individuals disperse. Otters in polluted river catchments experience reduced prey availability and potential toxin exposure that compromise welfare. River health and otter welfare are directly linked.