The Glenmornan River
Initially it was believed 2,000 fish perished in the incident in County Tyrone.
Now the Loughs Agency has confirmed the that 4,000 were killed
Local anglers have warned that the Glenmornan river in Artigarvan, near Strabane, may never recover from the fish kill.
Damien Devine, from Dennett Anglers’ Association, described it as a “complete wipe-out” and the worst he had experienced in more than 30 years of fishing.
Investigations are continuing to trace the source and extent of the pollution.
The incident was detected on Friday when fishery officers found large numbers of dead fish during a routine habitat survey in the area.
They included Atlantic salmon, brown trout, European eel, lamprey, flounder, stickleback and Stoneloach.
“Of particular concern is the loss of over 500 European eels, a species already in sharp population decline,” the Loughs Agency said.
“Additionally, the discovery of more than 20 dead frogs suggests the presence of a highly potent pollutant.”
The agency said the source of the pollution had been identified and the Northern Ireland Environment Agency (NIEA) was assessing the impact on water quality.
A spokesperson said: “All macroinvertebrate species appear to have been completely lost, highlighting the severe ecological impact.
“Anyone who discovers dead fish in the area is advised not to touch anything, and instead contact Loughs Agency directly on +44 (0) 28 71 342100 to arrange collection with a fishery officer.”
