Discovery of invasive crayfish in Lochaber

24th August 2011

North American signal crayfish, a small lobster-like species that can have a devastating effect on native wildlife has been found in a pond in Ballachulish Quarry according to The Highland Council. Scottish Natural Heritage (SNH) has confirmed the find.

This is the first time that signal crayfish, have been found in Lochaber and it is the most northerly recorded occurrence of this species on the west coast of Scotland.

Where they occur, signal crayfish can compete with fish for food and shelter, and they can be a significant predator of a range of freshwater animals. This means their presence is a threat to both conservation and angling interests.

Signal crayfish were first introduced to waters in England and Wales from fish farms in the 1980s. In Scotland, they were first recorded in the catchment of the Kirkcudbrightshire Dee in 1995. Since then, specimens have been found in ponds, rivers and lochs In Scotland, including the River Kelvin and the River Nairn (the most northerly location).

This species is a voracious predator which feeds on insects, frogs and young fish and their eggs. Signal crayfish also have an impact on the banks of rivers and lochs by burrowing into them. This can lead to increased erosion and damage to the spawning grounds of a variety of fish. In some situations it may cause some banks to become unstable.

Eilidh-Ann Madden, Highland Council's Senior Countryside Ranger for Lochaber said: "The crayfish were first discovered in the Ballachulish Quarry pond by one of our own Rangers earlier this month and we are extremely concerned by this. The site is currently owned by The Highland Council and managed by the Planning and Development Service for public recreation."

Immediately following the discovery Council rangers met with Scottish Natural Heritage and the Lochaber Fisheries Trust to discuss the issue. An appropriate course of action will be agreed following further dialogue.

Ms Madden added: "While there is no need to restrict access to Ballachulish Quarry pond for recreational purposes, we will be erecting signs to make the public aware of some sensible precautions in order to minimise the risk of inadvertently spreading the crayfish. I would urge anyone who visits the site to remember that it is illegal to catch or remove crayfish in Scotland without a licence. Members of the public who think they have seen signal crayfish anywhere else in the area should report this to the Lochaber Fisheries Trust."

Dr Colin Bean, Freshwater Advisor at SNH said: "We are very concerned about the spread of signal crayfish in Scotland as it presents a significant threat to native wildlife. It is disappointing to now find signal crayfish in relatively remote areas of the west of Scotland - the nearest population to this one is over 60 miles away at the River Kelvin - so it is clear that the Ballachulish population was established by humans. As it is against the law to capture, keep, transport or release live signal crayfish into the wild without a licence, the establishment of this population is the result of an illegal act."

Jon Gibb, Clerk to the Lochaber District Salmon Fishery Board, commented: "I urge the many hundreds of local and visiting anglers who fish our rich variety of rivers and lochs in Lochaber to remain highly vigilant for this potentially devastating invasive species and report any sightings immediately."

Sightings outwith Ballachulish Quarry should be reported to the Lochaber Fisheries Trust (Tel. 01397 703728, Email Lochaberfisheriestrust[AT]gmail.com).