More than 1,000 brown trout have been killed following a major pollution incident in Co Antrim.
The Department of Agriculture, Environment and Rural Affairs (Daera) has linked the Four Mile Burn fish kill incident to slurry.
The waterway in Newmills, close to Doagh, is a tributary of the Six Mile Water river.
Anglers were notified by the Northern Ireland Environment Agency (NIEA) of the fish kill on Friday.
In a statement and video posted on its Facebook page, the Antrim and District Angling Association (ADAA) said it was the latest major pollution incident to hit the area.
“Several of our members walked three miles of that stream and counted hundreds of dead fish from last year’s crop, and perhaps thousands from this season’s crop,” said the group statement.
“It’s incredibly frustrating that we find ourselves here again. Enough is enough, this has to end.
“These pollution incidents are the reason our beautiful Lough Neagh system is in tatters.”
The ADAA has called on Agriculture and Environment Minister Andrew Muir “to get a handle” on the situation.
Mr Muir’s Alliance Party colleague John Blair said fines and penalties should be increased for polluters.
“It is the only way polluters will learn and stop acts which risk our environment and its rich biodiversity,” he said.
The South Antrim MLA said he had reported another suspected pollution in the Three Mile Water River just days earlier.
“It’s immensely disappointing such occurrences are still happening, particularly when they take place in the catchment area of Lough Neagh,” he added.
“It destroys wildlife, damages natural habitats and threatens our environment as a whole. This incident has impacted salmon, which were already endangered locally.”
In a statement, Daera confirmed water quality inspectors from NIEA had been deployed to the area to assess the environmental impact.
A spokesperson said a joint investigation had been launched in tandem with Inland Fisheries.
Daera said the source of the pollution had been traced and NIEA officers had engaged with the owner of the premises involved on Saturday in a bid to prevent further spillage.
“From the assessment of the impact on the fishery, a major fish kill has been confirmed, with 1,109 brown trout of varying ages being killed.”