Invasive clam a threat to Barrow, Nore

Kilkenny residents are being asked to help stop the spread of the Asian clam in Ireland.

Kilkenny residents are being asked to help stop the spread of the Asian clam in Ireland.

An invasive species, the Asian clam (Corbicula fluminea) was first recorded in Ireland in the River Barrow near St Mullin’s in April 2010. The bivalve mollusc is regarded as one of the most notorious aquatic invasive species in the world.

Studies conducted by Inland Fisheries Ireland have revealed that it is firmly established in the lower Barrow, attaining staggering densities of up to 10,000 clams per square metre.

Considering that each clam can produce up to 70,000 juveniles each year, there is a potential for the enormous expansion of this population.

In late 2010 and in 2011, populations of the Asian clam were recorded in the River Nore downstream of Inistioge and in the River Shannon at Banagher and Carrick-on-Shannon and in Lough Derg.

The inadvertent introduction and transfer of the invasive Asian clam to uninfested waterways represent a major threat to Ireland’s habitats, native species and internationally renowned fisheries, according to Inland Fisheries Ireland. The ecology of invaded watercourses can become dramatically altered and may become unsuitable for water-based amenity and recreational pursuits.

At present, as water temperatures are increasing in Irish rivers and lakes, Asian clam populations are releasing vast quantities of planktonic juveniles into the water. The microscopic juvenile clams subsequently settle out of the water column, attaching to underwater surfaces using sticky threads.

In order to limit the further spread of this highly invasive species, Inland Fisheries Ireland is urging all water users, particularly anglers and boaters, to implement strict biosecurity measures including disinfecting all equipment that has been exposed to or used in waterways when moving from one area to another.

Further information is available on and Inland Fisheries Ireland also asks that any new sightings of the Asian clam be reported to the IFI.