An investigation into a pollution incident which killed thousands of fish in the Blackwater river in North Cork has failed to establish a source or cause, Minister of State with responsibility for Fisheries, Timmy Dooley, said on Thursday.
The inter-agency investigation by Inland Fisheries Ireland (IFI), the Environmental Protection Agency, Cork County Council, the Marine Institute and Uisce Éireann confirmed the mass kill was due to a chemical pollutant entering the Blackwater.
Mr Dooley said that testing of 28 brown trout taken from the river, alongside inter-agency investigations to date, have found that no specific factors could be conclusively established as to the cause of death.
He said technical teams concluded the most likely cause of the fish mortality was an irritant in the water, but the source and specific compound cannot be determined based on investigations.
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“It is deeply regrettable that the extensive work carried out to get to the bottom of this incident has not yielded any definitive results,” he said.
“I have requested a comprehensive inter-agency report on the investigation into this incident, as it will be important to understand how we can streamline our cross-agency response to these incidents, and ensure that we are identifying the sources of toxic pollutants in our catchments as quickly as possible.
“More importantly, we need to intensify our efforts to prevent these incidents from occurring in the first place. These fish kills have a devastating impact on the local community, the angling community, and everyone in these areas.”
Mr Dooley said that angling is continuing on the Blackwater, with no water quality issues currently detected. Uisce Éireann has been monitoring the Mallow Water Treatment Plant and found the water there was safe to drink.
He said while fish populations are expected to recover, IFI and other agencies recognise the significant impact the incident has had on the area. All agencies are continuing to carry out routine surveys and inspections to identify potential risks, both in the Blackwater catchment and more widely across other watercourses.
However, local anglers have expressed disappointment and fears of a repeat event if the source remained unidentified.
“It seems extraordinary with modern science and technology that thousands of fish could be killed on one of the country’s best trout and salmon rivers and after five weeks of investigation, we are no closer finding out what caused this catastrophic pollution incident,” said John Ruby, chairman of Mallow Trout Anglers.
He pointed out that 28 brown trout examined by Eurofins Environment Testing Ireland were taken from the Clyda tributary at its confluence with the Blackwater on August 26th and August 27th – over two weeks after the first dead fish were seen in the river.
The focus of the investigation, he said, seemed to have shifted to these latest tests on the live brown trout rather than the initial tests carried out by Marine Institute fish health experts who confirmed a chemical had killed ten dead trout taken from the river near Mallow on August 14th.
“It looks like we are back to square one as we are no wiser as to the cause of this fish kill and it just goes to show the state bodies that are supposed to protect our fish don’t appear to be able to do so because if they can’t find the cause, how can they guarantee there won’t be a repeat?” he said.
