Northern Ireland Water has apologised for a chemical leak which killed some 2000 fish in a Newcastle river.
It is understood that the leak came from a nearby NI Water treatment plant on Saturday.
In a statement NI Water said the pollution was due to an accidental discharge of polyelectrolyte, which is used in the sludge thickening process, from Annsborough Waste Water Treatment Works.
“We are very disappointed and extremely sorry this incident has happened,” NI Water said.
“The cause of the discharge was identified and immediately fixed on Saturday evening and there is no further risk to the river. The immediate focus now is on working with NIEA and local anglers to assess the impact and the needs of the river in terms of re-stocking the fish.”
Ed Kilgore, a committee member of Shimna Angling Club, told the BBC that local clubs had been “robbed of this season’s fishing” and that even with restocking the health of the river could be affected “for the next three years”.
The Assembly’s Agriculture Committee Chairwoman Linda Dillon expressed concern and disappointment.
“The Annsborough River is an important tributary for local anglers and this latest incident could have very damaging long term effects for fishing in the area as well as the future health of the river and the surrounding natural environment as a whole,” she said.
“While we welcome the fact that NI Water has taken responsibility and acted quickly to halt the discharge into the river and to initiate the clean-up operation; it is crucial that the necessary remedial measures and regular checks are put in place to ensure that similar incidents do not occur in the future.”
South Down MP Margaret Ritchie said she was “dismayed” by the news. NI Water needs to carry out a proper investigation and carry out immediate works to repair the problems, she said.
It must also publish a delayed report on Dundrum water treatment works, she said.