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Click here to go back Details of this species in England Status: Alien Invasiveness: Invasive Occurrence: Reported Source: MacDonald and Harrington, 2003 Arrival Date: 1929 Introduction: Unintentional (accidentally) Species Notes for this Location: Mustela vison (American mink) were introduced to the United Kingdom for fur farming in 1929. They established feral populations on the mainland in the 1950s and 1960s, following releases and escapes from these farms, and have since rapidly colonised the waterways of Britain. Mink are now found at relatively high densities in south-west England, west Wales and west Scotland. They are not found in north-west Scotland or north-west Wales, but are spreading into East Anglia and east Yorkshire. In 1990, the mink population was estimated to be 110,000, with 9750 in Wales, 46,750 in England and 52,250 in Scotland (Harris et al., 1995; in Macdonald et al., undated), and since then the population is estimated to have declined by half to two-thirds (Strachan, pers. comm., in Macdonald et al., undated). It is possible that American mink have taken over the niche left vacant by the heavily persecuted polecat (Mustela putorius). The recent increase and expansion of otter (Lutra lutra populations in the UK could impact negatively on mink populations, as there is evidence that otters have a dramatic impact on mink densities and distribution, most likely due to interference competition (Bonesi and Macdonald, 2004). The average density of mink in Britain is about 0.35 mink/km of river, depending largely on availability of rabbits. Population modelling shows that the maximum number of mink which Britain could sustain without anthropogenic control is approximately 378,600 (Macdonald et al., undated). A study undertaken in southern Britain revealed that the main prey item in the diet of mink is rabbits, followed by fish, small mammals, and coots and moorhens (Rallidae family) (Ferreras and MacDonald, 1999). Management Notes for this Location: Section 14 of the Wildlife and Countryside Act 1981 prohibits release or escape of American mink into the wild (Macdonald et al., undated), and fur farming is now outlawed (Fur Farming (Prohibition) Act 2000; in Reynolds et al., 2004). In England and Wales, mink have been controlled using three main methods (Macdonald et al., undated): trapping, hunting with hounds on foot, and shooting. Trapping (killing or live capture traps) is the main method used. In the 1960s, the Ministry of Agriculture, Fisheries and Food trapped over 5000 mink in England and Wales, with a similar effort occurring in Scotland by the Department of Agriculture. By the mid 1970s, the attempt was seen as futile and was abandoned. More recently, trapping is used as a conservation tool at water vole sites, as well as by farmers, gamekeepers, angling clubs etc. Hunting with hounds was also widespread. An estimated 400-1400 mink were killed by registered minkhound packs annually (many of which previously hunted otters prior to this species' protection), until hunting with dogs was made illegal in 2005 in England and Wales. Conservationists believe that mink hunting has the potential to cause disturbance to other wildlife, such as otter. Shooting is mostly ad hoc, carried out by farmers and gamekeepers. The majority of mink are killed during winter or in autumn when juveniles are dispersing. It is unlikely that any current method of control in the UK could achieve eradication, and it is recommended that mink control be prioritised in areas of high conservation concern, such as areas with populations of water voles. Macdonald and Strachan (1999; in Macdonald et al., undated) recommend that control is carried out between January and April in the UK, to target breeding females. In lowland England, the recovery of the otter may work against the mink, but recovery of the European polecat (Mustela putorius) will make mink trapping more problematic. Location Notes: Impacts: Disease transmission: There is evidence of Aleutian disease in feral American mink in the UK. Yamaguchi and Macdonald (2001) found antibodies to Aleutian disease virus (ADV) in 51.9% of a sample of mink in southern England (in Hammershoj, 2004). Economic/Livelihoods: Mustela vison impact on salmonid fisheries, trout farms, salmon farms and commercial carp ponds (especially exotic koi carp) (Macdonald et al., undated). Predation: Mustela vison impact on ground-nesting birds in freshwater systems and in the marine environment on offshore islands. Burrow-nesting shelduck are vulnerable to the arrival of mink on the islands of Loch Lomond, as are puffins and shearwaters (Bignal, 1978). The decline of white-clawed crayfish (see Austropotamobius pallipes in IUCN Red List of Threatened Species) may be accelerated by mink predation (Smal, 1991). Mink may affect the numbers of the common scoter (see Melanitta nigra in IUCN Red List of Threatened Species) by predation (Underhill et al., 1998; in Cranswick, undated). American mink are thought to be one of the main factors contributing to the decline of the European water vole (see Arvicola terrestris in IUCN Red List of Threatened Species) in the UK. Water voles are an important species in the diet of colonising mink (MacDonald and Harrington, 2003). In southern Britain, mink appear to negatively impact on coot coot (see Fulica atra in IUCN Red List of Threatened Species) populations (Ferreras and MacDonald, 1999). Last Modified: 13/03/2006 12:34:08 p.m.