July 21, 2009
Press Association National Newswire

A breeding programme has begun to save Britain's native crayfish from being wiped out by foreign species.

The rare white-clawed crayfish will be transported into secret safe havens in an attempt to halt the takeover by the more aggressive, disease-carrying American signal crayfish.

The American signal crayfish were introduced in the UK 20 years ago and have wiped out almost 95% of the native species.

Conservationists have warned that the white-clawed crayfish faces extinction from UK waters within 30 years unless new populations can be created in safe, uncontaminated waters.

The South West White Clawed Crayfish Conservation Group has begun trapping British crayfish and transferring them to "safe haven" breeding sanctuaries.

These so-called 'ark sites' are freshwater pools at locations in the South West, where the population has been hardest hit.

The 210,000 project will run for two years and is funded by Natural England.

It is led by the Bristol Conservation and Science Foundation in partnership with the Avon Wildlife Trust and the Environment Agency.

Jen Nightingale, the UK conservation officer for the foundation, said: "White-clawed crayfish were abundant and easy to find until the American signal crayfish species was introduced to UK waters in recent years.

"The American species not only out-competes native crayfish for resources, it also carries a disease, the crayfish plague, which is fatal to UK crayfish.

"We now believe that three quarters of native crayfish populations in the Bristol Avon catchment area have been wiped out.

"The native crayfish population in our target area has been categorised as highly at risk of being infiltrated by American signal crayfish or crayfish plague, so we decided to catch enough individuals to form two new populations in designated safe sites.

"Both sites are isolated water bodies with little chance of being affected by American Signal crayfish.

"We want to keep these locations secret to prevent people visiting the areas and risk spreading crayfish plague - which can be carried on damp equipment and boots as well as in water.

"People who visit rivers, ponds and lakes can help prevent the spread of disease by washing and drying equipment after use.

"We'd also like to encourage people to report crayfish sightings - of any species - to the Environment Agency."

The first relocation day involved staff and volunteers from Bristol Zoo Gardens, the Avon Wildlife Trust and the Environment Agency, who moved a number of crayfish in chilled containers from South Gloucestershire to two new sites in Somerset and North Somerset.

Similar schemes are also planned for sites in Wiltshire, Devon and Bristol.

Pete Sibley, from the Environment Agency, said: "It was important not to harm the resident ecology when transferring the crayfish to new sites and exhaustive tests had been undertaken to assess the new habitat and ensure that there was a high water quality, tree cover with leaf litter, and rocks and boulders for refuge.

"This type of rescue mitigates the threat from signal crayfish by actively conserving natives through seeking out safe refuge sites.

"Efforts to eradicate American Signal Crayfish have to date proved unsuccessful."

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