Invasive species are animals and plants that move into areas where they are not native and then become abundant enough to cause problems.

Once established in a habitat, it is extremely difficult to remove them and they can have detrimental impacts on both people other wildlife.

Japanese knotweed, one of the worst examples of an invasive species, can not only completely dominate river banks, suppressing native flora, but can also grow through concrete and tarmac, causing major economic damage estimated at over £150 million annually.

Floating pennywort costs around £20 million annually, including the cost of removal and the impact on boat transport and other access to water bodies.

Giant hogweed can cause severe skin irritations to those who touch it. Gyrodactylus, a worm-like parasite, has decimated salmon populations in Norway and could well do the same if it establishes in this country.

Other invasive species might not have the same direct effect on people, but can be equally disruptive to the native environment, outcompeting or preying upon native species and driving some to local extinction.

Think of the effect of introduced American mink on populations of water vole in this country, now a rarity across most of its range; the grey squirrel replacing the red; or the signal crayfish, whose impacts have wiped out the native species across most of England, leaving Cumbria as one of its few strongholds in England.

The waters of the Lake District already play host to many invasive species. At the same time, we are fortunate to have been spared from some worrying ones, such as zebra mussel, killer shrimp and floating pennywort.

Once these species arrive, we will be stuck with them, and our environment and finances will suffer.

So, can we stop them from getting here? There is no guarantee, but we can certainly try.

Invasive species are often spread by accidental human transfer: aquatic species can be moved around as stowaways in angling gear, boats, water sports equipment, anything that may be carrying a bit of water from one lake to another.

The killer shrimp, for example, can survive for two weeks in the damp folds of a pair of waders, so a few days in some water in the hull of a boat, a hollow trailer or an angler’s kit bag would be no problem at all.

So, to stop the spread of these plants and animals, we need to be serious about ensuring that precautions are put in place to stop their movement.

An awareness campaign targeted at people moving equipment around needs to be the centrepiece of our efforts.

Visitors to Ireland may be familiar with the very visible notices by most loughs and fishing rivers, warning of the dangers of transporting zebra mussels. A similar campaign here, wherever boats are launched or anglers congregate, could warn of the problem species.

At the same time, targeted education will reinforce the message. Last year the Government launched a ‘check, clean, dry’ campaign: check your equipment before moving it; clean it to remove stowaways, and dry it thoroughly between uses to kill persistent species such as killer shrimp.

Publicity about this campaign, and the reasons behind it, needs to be targeted at visitors and residents alike in fishing clubs, hotel rooms, equipment suppliers, boat licence renewal letters, etc.

We are one of only two English counties to have a freshwater invasive species initiative (www.scrt.co.uk/cfinns) and an invasive species officer, so there is expertise on hand to provide the advice needed. Publicising the problem now may save us from a lot of problems in the future.

  • Dr Michael Dobson, director of the Freshwater Biological Association