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The North American mink - Mustela vison
Helle Ruth Isaksen, veterinary student, 1st year
North American mink has been introduced to many countries, among other
countries; Norway, for commercial fur production. Mink who have escaped
death at Norwegian fur farms have found their place in our ecosystem and
have resulted in large breeding populations in the wild.
The North American mink, Mustela vison, is a member ofthe family Mustelidae. This carnivore has an elongated body approximately 65 cm long with the tail, and it has short limbs. The mink has the size of a small housecat, the male being heavier then the female. Their weight is 0,5-1 kg. Wild native American mink are uniformly dark brown with a light spot under the chin, but breeding in fur farms has resulted in a wide range of fur colours, and consequently escaped feral mink may vary in colour ffom white, grey or fawn through to black. The fur does not let water through, this is good since the mink live most in the water. They are great swimmers and divers. The mink also live on land. They don't have a natural enemy, and no of the Norwegian carnivores manage to catch the mirik because oftheir intelligence and enormous capability to run fast.
American mink is a semi-aquatic, generalist predators and its main food
consist of fish, birds( eggs, nestling as well as adults), small mammals
and amphibian. (http://bio.univet.hu/SAL VE/student- essay/libr/mink -
baltic.pdt) They are very adaptable and can exploit a wide range of foods.
They are also known for raiding poultry houses. I will concentrate about
their meals when it is about birds, mainly wading birds, and fish. This
is because I know that the mink could be a problem in these area.
The species was introduced into many countries throughout the world,
one of them Norway, from about the 1920s, as an animal farmed for its
fur. Many animals escaped, and started to breed in the wild. The mink
adjusted itself to the nature in Norway very fast, mainly because the
norwegian nature is almost equal to the one in North-America. Under the
second worldwar many of the minks were released because the farmer didn't
have enough food to feed themselves and the animals. In more recent years,
large numbers of mink have been deliberately released from farms by animal
The mink is also a competitor with species we have naturally in the norwegian fauna, for example otter (Lutra lutra). They have the same habitat, live in the near of water and eating mainly same food, fish, especially in the winter. This invading species may therefore pose a risk to the otter through competition for food and territories. Norwegian researchers are not sure if this can result in habitat loss for some of the species, or if the overhunting can lead to lacking of food for their arrival.
The Aleutian mink disease parvovirus (ADV) is commonly found in American mink on fur farms. This disease is highly persistent in the environment and can be spread either from mother to offspring, or via contact with urine, faeces or saliva. In addition to direct mortality, infection with ADV can cause decreases in fertility and spontaneous abortions. It is possible that farms may act as a source of the disease but more work is required to determine the prevalence ofthe disease in the wild.(http://www.ccs.st-and.ac.uk/mink.php)
It is now clear that populations of some species do suffer with the introduction of American mink into the local fauna, especially wading birds and fish. There are several potential problems associated with mink for native wildlife. For native wildlife, mink may be considered a threat as predators, competitors or as vectors of diseases. The large population of mink are damaging parts of the norwegian fauna.
In researches on small islands in the Baltic sea it is proofed that mink removal increases breeding densities of many birds species in that habitat. This is why norwegian hunters get rewards for killing the mink. If we weren't allowed to hunt on them, I think maybe some species would have died out, especially some of the wadingbirds.
http://bio.univet.hu/SAL VE/student essay/libr/mink baltic.pdf
http://www.hordaland-f.kommune.no/sti/Natforv%202b/MINK.htm->siekk http://www.nocompromise.org/news/norway.html http://www.ccs.st-and.ac. uk/mink. php
Helle Ruth Isaksen, l.year wildlife ecology,2004
|Notes (if any) by Peter Kabai: accepted|