The recovery of otter populations across Britain and Europe following near-extinction from pesticide pollution is a conservation success story that also brings welfare considerations for otters in expanding ranges.
Recovering otter populations face new welfare challenges as they re-colonise previously uninhabited areas. Road crossings are a primary mortality source, with many deaths occurring at culverts that force otters to cross roads. Otter ledges under bridges and otter-friendly culvert designs significantly reduce road mortality. Entanglement in fishing gear, particularly eel fyke nets and fish traps, is also a source of welfare concern. Young otters that have failed to establish territories may suffer food stress in areas with degraded fish populations.