Like the Otter, The American Mink Nevision vision (Mink hereafter) is a member of the Mustelidea family. However, unlike otters and the other UK Mustelids (e.g. stoats, weasels and badgers), Mink are non-native in Britain and considered an invasive species. Mink grow up to 70cm in length, with females weighing around 1kg and males 1.5kg. Mink can be confused with otters. The two species have similar diets (both prey on fish, crustaceans, birds and small mammals) but Mink are considerably smaller animals and are non-native.
Mink are present across the UK mainland and first arrived in 1929 where they were reared in captivity for their once sought after fur, which varies in colour from light brown to black. Many escaped captivity and the species range spread. Since their introduction, Mink have played a significant role in the decline of our native water voles and have had a negative impact on many other species including many ground nesting birds. Thus, the species is identified by the Joint Nature Conservation Committee and humane control of mink is recommended under the UK Biodiversity Action Plan. Any trapped Mink must be humanely euthanized as it is illegal to release them into the wild. More information on control of mink and approved methods can be found here.
The following scientific paper may also be of interest.