Brown trout, stickleback, minnow and lamprey affected. Picture courtesy of Inland Fisheries Ireland

The Inland Fisheries Board of Ireland is investigating a large fish kill that occurred in the River Tolka at Mulhuddart Road Bridge.
On August 6, hundreds of fish were found dead in the river just under the bridge.
At about 2pm locals reported a large amount of fish jumping repeatedly out of the water. Just an hour and a half later, the fish were either dead or dying.
John Hennessy of Tolka River Environmental Alliance (TREA), said the affects of this “deliberate pollution or neglect” is that work carried out on this stretch of river over the last number of years by both young members of the TREA and the Inland Fisheries Board of Ireland has been “wiped out in a couple of hours”.
“The terrible thing about the trout killed is that they were almost all wild fish that were at or nearing spawning age.
“These fish were put into the river by TREA in partnership with the Fisheries Board at unfed-fry or fingerling stage [young fish ready to start feeding] and as part of the Trout in the Classroom project run by Foroige. It has taken the river and the fish this long [about eight years] to reach a stage where we have a fairly large regenerative stock.
“Young members of TREA are continually taught to respect their environment and volunteer leaders put a lot of effort into training young people in how best to maintain the river and its environs.
“Such pollution as has happened undermines this work and is completely unacceptable,” John added.
He went on to say “thankfully” the fish kill was confined to the Mulhuddart/Castlecurragh stretch of the river.
A spokesman for IFI said the investigation was initiated following a complaint about the dead fish.
“Approximately 300 adult and juvenile brown trout, large numbers of stickleback and minnow and a small number of lamprey were killed over a section of main channel approximately 650m long. Live fish including brown trout were recorded in the affected area during the investigation.
“The fish were judged to have died within approximately 12 hours of the report being received. Samples were taken for analysis – however results did not identify any deleterious matter which may have caused the kill.
“IFI are currently liaising with Fingal County Council in an ongoing investigation of local surface water drainage systems in an effort to determine what may have happened and with a view to preventing similar events in the future,” the spokesman added.