Dire straits for 'outlaw' limpet

The "Wanted" posters are staying up for a US shellfish which became a pest in a marine biodiversity hotspot.

Slipper limpets were mistakenly brought on baby mussels to the Menai Strait between Anglesey and Wales' mainland.

Efforts to clear the sea snail, which competes with mussels and oysters, saw 1,200 tonnes of mussels removed and beds re-laid with "clean" specimens.

Assembly officials say it was successful but it is too early to declare the area slipper-limpet free.

In July, the Countryside Council for Wales (CCW) issued Menai Strai mussel farmers with 'wanted' cards of alien shellfish species.

Invaders listed included the violet sea squirt and Chinese mitten crab as well as the slipper limpet.

The American interloper was confirmed in February 2007 as being in the waterway, named by environmental group WWF as one of seven of the most valuable areas in the UK for marine biodiversity.

"It is not possible to state categorically that there are no slipper limpets in the area, mainly because of the possibility that small numbers remain undetected"
Welsh Assembly Government

Slipper limpets, or crepidula fornicata, cause problems for shellfish farmers by competing with native species for food and space.

The mussel industry responded by replacing possibly infected mussels and a survey in September 2007 by CCW and the North Wales and North West Sea Fisheries Committee found two empty shells, but no live slipper limpets.

However, no-one seems to be betting their bottom dollar that the outlaw has been eliminated.

A Welsh Assembly Government spokesperson said: "There have been concerns about the possible continued presence of slipper limpets in the Menai Strait.

"It appears that the industry was successful in removing the slipper limpets which were accidentally introduced in 2006.

"They may even have succeeded in eradicating the animal as there is little or no evidence showing that slipper limpets have become established in the Menai Strait.

"However CCW have advised the assembly government that it is not possible to state categorically that there are no slipper limpets in the area, mainly because of the possibility that small numbers remain undetected.

"Given that situation, it would be premature for WAG to declare the area free of slipper limpets at this time."

The assembly government said reviews of the situation would continue.

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Countryside Council for Wales
North Western and North Wales Sea Fisheries Committee
Welsh Assembly Government
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