Suspicion grows Asian clam was deliberately introduced

From the Irish Times:

Suspicion grows Asian clam was deliberately introduced

THE POSSIBILITY that the latest invasive species discovered in Irish waters, the Asian clam, may have been deliberately introduced to be harvested at a later date is being investigated.

The finding of “a well-established, high-density colony” of the freshwater Asian clam in the river Barrow at St Mullins, south Co Carlow, has alarmed fisheries officials and wildlife experts.

Dr Joe Caffrey of the Central Fisheries Board said it posed a threat to salmon, trout and other native species such as the freshwater pearl mussel. The “invader” could damage the food chain in Irish rivers and fatally harm the gravel beds which are used by fish as spawning grounds.

Last week, divers from the Central Fisheries Board entered the river and recovered “400 live beasts” which caused Dr Caffrey to “despair”.

He said “we don’t know how long it has been here or how far it has spread” but fears “the clam may already have spread to other rivers including the Nore and the Suir”. Further diving trips are planned next week.

It is not known how the species arrived in Ireland and, although the Barrow is tidal at St Mullins, it is not believed to have arrived by boat because the creature lacks the ability to cling to a hull.

Dr Caffrey said the Asian clam is used in aquaria and ponds and, initially, he thought it “might have been released by someone dumping the contents of an aquarium into the river”.

But now he is “suspicious” that it may have been “purposely introduced” to create a food source. “Asian clams do make a nice meal,” he observed.