American mink escaped from fur farms to devastate UK water vole and ground-nesting bird populations, requiring management that raises welfare questions for a sentient invasive species.
Mink are highly intelligent, curious mustelids capable of significant suffering. Live trapping causes stress and confinement before lethal management. Body grip kill traps cause rapid death when properly set but wounding when mis-set or damaged. The welfare harm of management must be weighed against the conservation welfare benefits to water voles, terns and other vulnerable species. Research into non-lethal population management through immunocontraception is at an early stage.