The Northern Ireland Environment Agency is asking River Lagan users to be on the look out for a highly invasive plant species after one of Ireland’s most unwanted species Floating Pennywort (Hydrocotyle ranunculoides) was discovered in the River Lagan.

Investigations are ongoing as to how it made its way into the River Lagan.

John Early, from NIEA, said: “Floating Pennywort is a highly invasive aquatic plant that could potentially establish in the slower moving margins and slower flowing ditches which flow into the River Lagan.

“It is important that users of the River Lagan keep a look out for this species and inform authorities of where they have seen it so that it can be removed”.

Floating Pennywort, a freshwater invasive aquatic plant, is native to North America. It was first brought into Ireland as a plant for tropical aquariums and ponds, but it has since escaped into the wild at a limited number of locations in Northern Ireland. Once established it is capable of quickly forming thick floating mats across the waters surface.

Dr Robert Rosell, from Agri-Food and Biosciences Institute (AFBI) said: “Floating Pennywort is capable of growing at a rate of 20 centimetres a day enabling it to quickly take over the habitat in which it occurs.

“Other sites such as Glastry Clay Pits have demonstrated the serious impact this plant can have on our freshwater environment."

Following on from the discovery the Northern Ireland Environment Agency, Agri-Food and Biosciences Institute and Dromore Angling Club instigated a rapid response clean up operation in a bid to prevent this highly invasive plant from establishing. An estimated five to six tonnes of Floating Pennywort have so far been removed from the River Lagan in this joint rapid response operation.