An alien species of crayfish, which has devastated fish stocks in lochs and rivers, has been been removed from a quarry pond in the Highlands.

The Highland Council and Lochaber Fisheries Trust have confirmed confirm that, so far, eradication of North American Signal Crayfish in Ballachulish Quarry appears to have worked.

The crayfish, a small lobster like species, were first discovered in the pond by one of the council's countryside rangers in 2011.

The site is 60 miles from the species' next nearest habitat - the River Kelvin, near Glasgow - and scientists believed specimens may have been taken there by someone hoping to provide a food source for fish or to harvest them.

It was and is illegal to transport the species as the crayfish is a voracious predator that feeds on insects, frogs and young fish and their eggs.

It wiped out stocks of fish in Loch Ken, near Castle Douglas in Dumfries and Galloway, despite a Government scheme to trap and kill more than a million crayfish there.

The discovery in Lochaber was the first time it had been found as far north on the west coast.

In 2012 it was announced attempts would be made to eradicate them by adding the toxic chemical Pyblast to the Ballachulish ponds.

The council, which owns the quarry, now says that periodic monitoring since that time indicated the complete absence of the species from the quarry waters, which was a major achievement for the benefit of conservation and fisheries in Lochaber.

Commenting on behalf of the Lochaber Fisheries Trust, Diane Baum said: "'We are very encouraged by the monitoring to date. It is a little too early to be completely confident we removed every last crayfish from the ponds, but at this stage we are cautiously optimistic about the success of the project."