The fish kill was reported in the Four Mile Burn, which is a tributary of Six Mile Water. It is believed the incident happened above the village of Parkgate.

South Antrim MLA Mr Blair said it was time fines for polluters were increased.

“It is a deeply concerning incident and could have a major impact on local fish populations,” he said.

“It comes just days after I reported an incident of suspected pollution in the Three Mile Water River, also in South Antrim. It’s immensely disappointing such occurrences are still happening, particularly when they take place in the catchment area of Lough Neagh. It destroys wildlife, damages natural habitats and threatens our environment as a whole. This incident has impacted salmon, which were already endangered locally.

“In Alliance’s five-point plan for Lough Neagh, we called for increased fines and penalties for polluters. It is the only way polluters will learn and stop acts which risk our environment and its rich biodiversity.”