A miniature clam which threatens valuable river systems and could interfere with flood controls has been discovered in the Shannon, fisheries chiefs have warned.
The Asian clam was first spotted in the River Barrow in April and has since been found on the river bed around Carrick-on-Shannon.
Dr Joe Caffrey, Inland Fisheries Ireland senior research officer, said it could have considerable implications for the Shannon.
"This clam can effectively eliminate large components of our native aquatic fauna and flora, will block intake pipes and could interfere with recreational exploitation in infested rivers," he said.
"We must stop it spreading further within the Shannon and accessing many of the connected watercourses on this great river system."
The tiny clams are believed to be less than a year old and fisheries chiefs are hoping this may make it easier to prevent them spreading.
The Asian clam causes about one billion euro damage in the US each year and can impact on native salmon and trout, significantly alter river habitats through shallowing, block pipes and disrupt flood control.