To control an American mink population is to reduce its size. To eradicate a population is to reduce its size to zero. A control project that reduced a population by 99.9% would be considered an enormous success, whereas an eradication operation that did so would be an utter failure. That final 0.1% may seem to be a minor issue, but it’s a good illustration of why control and eradication are two very different concepts.
American mink control has been an extremely important nature conservation tool in Britain for decades. By substantially reducing the number of American mink in any area, native species like water voles may thrive when otherwise they would cease to exist. Moorhens and reed buntings can suddenly reappear; sand martin colonies may be re-occupied. Nature is quick to recover, given half a chance. But such recovery lasts only as long as the trapping effort, and the trapping effort normally lasts only as long as the money and the enthusiasm of volunteers. In most cases, the respite is temporary; American mink return as soon as the money runs out, and we’re back to square one.
For this reason, eradication, if it can be achieved, is by far the best option. In the long term it is cheaper, more humane and far more beneficial for wildlife. If it can be achieved, the eradication of American mink in Britain would mean the end of mink trapping, the end of water vole reintroductions, the end of the desperate search for money to prolong trapping operations, and the beginning of a recovery of all waterside wildlife across this vast island of ours.