A pollution incident in a tributary of the river Faughan near Claudy, Co. Derry is suspected to have been caused by silage effluent, a DAERA spokesperson has said.

In a statement on Wednesday, the spokesperson said that the estimates suggest that in excess of 1,000 fish of a range of species have been killed over several kilometres of river.

“Staff from Loughs Agency, who are leading this investigation, are working closely with NIEA (Northern Ireland Environment Agency) to quantify the number and species of fish affected, and the cause, which is suspected to be silage effluent,” the spokesperson said in the statement.

The incident was first brought to the attention of NIEA on Monday evening and at present the source of the pollution has not been located.

Investigations involving electro-fishing and other techniques are being used by Lough Agency staff and NIEA staff are carrying out river walks to source the cause of the pollution.