Minister of State for Fisheries and the Marine Timmy Dooley has asked Inland Fisheries Ireland to bring together the Environmental Protection Agency, Cork County Council, Uisce Éireann and other relevant agencies to trawl back through, and analyse, whatever data is available to get to the bottom of what caused the fish kill on Blackwater River at Mallow ten days ago.
It follows preliminary results from an analysis of fish samples by the Marine Institute earlier today which concluded the fish died as a result of a so-far unknown environmental irritant.
The investigation confirmed that whatever impacted the water in the Co Cork river had damaged the gills and the eyes of the fish swimming there, yet there was no evidence of bacterial infection or systemic disease.
There was speculation last week that the kill may have been caused by a fungal infection, disease, low water flow, or high water temperatures but today's preliminary results suggest this was not the case.
Anglers in the region, who estimate that over 40,000 fish may have died in a 30km section of the river, are particularly concerned that the source of the fish kill is identified to ensure that it does not happen again.
Inland fisheries Ireland estimated that the number of dead fish, which it said were mostly brown trout, was between 8,000 and 10,000 along an 18km stretch of the river.
However, local anglers who pulled thousands of the dead fish from the water said every species present in that section of the river was affected including stickleback, trout, salmon parr, adult trout, dace, roche, salmon and freshwater eels, which are an endangered species.
The anglers estimated that the number of fish killed was about 46,000 over a 30km stretch of the river and said that this makes it the largest fish kill in the history of the State.
The Environmental Protection Agency said it had inspected all EPA-licensed industrial sites and urban water discharges in the area on the day the fish kill was discovered but that its investigations are ongoing.
