Plague to wipe out local crayfish (From Wilts and Gloucestershire Standard)

Plague to wipe out local crayfish

A DEVASTATING plague brought to the UK's waters from across the Atlantic has wiped out tens of thousands of crayfish in North Wiltshire.

Just after Christmas, a Sherston resident discovered hundreds of dead white clawed crayfish as he walked his dog alongside the stretch of the River Avon that runs through the village near Grove Wood.

The Environment Agency (EA) was called in and carcasses sent to the government run Cefas laboratories in Weymouth.

Last Friday test results confirmed the biggest outbreak of the crayfish plague in the area for 25 years.

The North American signal crayfish, a bigger and more aggressive relative of the white clawed species native to this country, carries the plague.

The signal was brought to this country in the 1970s to be farmed for food.

It has subsequently taken over and introduced the fungal disease to which it is mostly resilient, although the native crayfish is not.

Environment Agency officer and crayfish expert Martin Frayling dealt with a catastrophic plague outbreak in the Bristol River Avon in 1981.

After reintroducing the native species successfully in 1983 some 6,000 to 8,000 more were killed in April 1998 following a leak of sheep dip into the Sherston Avon and Luckington Brook - the site of the latest disaster.

Having worked so hard to again build up the native crayfish populaton, Mr Frayling said: "This is the biggest one we've had since 1981 and it's substantial because you are talking about thousands of crayfish affected. It is very sad.

"It's going to wipe everything out, there's no doubt about that.

"We are expecting total kill because that's what this plague does."

How the plague spores got into the Sherston Avon is unknown, said Mr Frayling, because there are no signal crayfish there.

It is possible the spores, which can live out of water for weeks, were transported to the river on anglers' equipment or waders, by birds, hikers crossing rivers or any number of means, explained Mr Frayling.

Anglers have now been urged to comprehensively wash their equipment after visiting each river.

So far no dead crayfish have been found in either the Malmesbury or Tetbury branch of the Avon, but the EA is monitoring the situation.

However, American signals have been found in the Malmesbury Avon, said Mr Frayling.

He added: "It means those crayfish will now hold the plague in the River Avon so that means there will be no reintroduction (of native crayfish).

"It means the crayfish plague is now in the Avon. We can't do anything other than monitor the situation. You are talking possibly hundreds of thousands of dead crayfish ultimately."