Eurasian otters have recovered dramatically in UK rivers since the nadir of the 1970s, but habitat quality, pollution and road traffic remain serious ongoing welfare and conservation threats.
The recovery of UK otter populations is one of conservation's genuine success stories, driven by pesticide regulation, cleaner rivers, and legal protection. But recovered populations face new pressures: road traffic fatalities are now the primary mortality cause, particularly where dual carriageways cross river corridors. Each otter killed on a road has likely spent years establishing a territory and may be a parent of dependent cubs. Otter-friendly road modifications — passages under busy roads, improved bank management around culverts — can dramatically reduce road mortality at modest cost.