Village fights back by killing and eating its alien invaders

Diners in Surrey are enjoying the fruits of a battle to save a fragile ecosystem from unwelcome interlopers.

They say revenge is a dish best served cold. So it is with the picturesque Surrey village of Shere, located on the River Tillingbourne, which usually draws tourists with its quintessentially English charm. But locals have been spurred to take drastic action against an American invader: killing and eating them – chilled – as fast as they can catch them.

The incomers are American crayfish, whose ever-increasing population is threatening the survival of the native British species, both in the Tillingbourne and nationwide. In the past 20 years, over 95 per cent of British crayfish have been wiped out by their American counterparts.

The species, native to the western Pacific Ocean, was originally introduced to Britain in 1963. However, they escaped from their lagoon enclosures and can now be found breeding in every European country. They then eat everything in their habitat, disrupting the eco-structure.

In their natural habitat, the crayfish encounter predators, such as alligators and the painted turtle, which control their fertile population. But in Britain the species has multiplied dramatically, taking food away from native white-clawed crayfish, and infecting them with a deadly water mould.

The American variety is now a popular delicacy at The William Bray restaurant in Shere, which sits only 50 yards from the river. Head chef Mark Routledge's speciality dish, "Chilled Tillingbourne Crayfish Bisque with Bloody Mary Ice Cubes and Cucumber Spaghetti", has proved to be a hit since its introduction six weeks ago. "I suppose it's a bit like Marmite, you either love it or hate it," he said. "But people keep coming back for more; it's nearly always sold out."

Two months ago Jim Storrar, an ecologist, began trapping the crayfish and selling them to Mr Routledge for a knock-down price of £5 per kilo, compared with the usual £14 per kilo. He had originally intended to cull the crustacean for ecological purposes only.

"This American species eats everything in sight," explained Mr Storrar. "The river then becomes less diverse, and eventually it will go sterile. That will mean eventually the animals at the top of the food chain, like heron and trout, will have no food left."

The alien species also represents a threat to canals and dams. "The problem is, they love digging their own tunnels inside of the mud banks, which damage the canals and earth dams on top," said Mr Storrar. "It all equals a failure in the infrastructure of our waterways – river systems with banks will erode faster because of them."

While trapping is the only effective method to eliminate the aquatic nuisances, Mr Storrar said it does not always work. "Everybody would have to start trapping crayfish daily and it would take several years to work," he added. "No one bothers doing that for ecology. I suspect nature's going to be left to sort the problem out, as always."