Find raises concern over spreading of species

Investigation work has been planned following reports of crayfish discovered in another Scottish river.

The North American signal crayfish blamed for destroying habitats in waterways has been discovered in the River Nith for the first time. The species was first found in Scottish waters in 1995 and is thought to be spreading throughout the UK.

Scottish Natural Heritage (SNH) is soon to carry out surveys to confirm whether or not the species does habit in Nith, after the waters of Loch Ken in Dumfries and Galloway became infested.

It is thought that the crayfish are spreading due to escapes from fish farms or illegal releases, and concern is rising because the species is extremely difficult to eradicate.

SNH freshwater adviser Dr Colin Bean said: "The prospects of removing signal crayfish from any water body - particularly one the size of the Nith - is likely to be difficult if not impossible. So it is important for us to know what is actually there before any moves are made to try and develop any containment."

It is illegal to remove crayfish, however, anglers finding the fish have been advised to let either SNH or the Scottish Environment Protection Agency know.