Marine engineers are to rebuild part of a controversial weir in Kilkenny city, after it emerged that it was blocking salmon from returning up-river to spawn.
Yesterday, as up to 20 dead salmon were found downstream from the weir, fisheries staff and the Office of Public Works (OPW) began to draw up plans to alleviate the blockage.
The weir, in the centre of the city, was part of a €48 million flood relief scheme on the River Nore, which was criticised last year by the Comptroller and Auditor General for costing four times its original estimate of €13 million.
Yesterday local Fianna Fáil TD and deputy chairman of the Public Accounts Committee (PAC) Mr John McGuinness said he believed the blockage was connected with the dead fish.
"We have already had this €48 million project before PAC," he said.
"Now we're looking at an ecological disaster because they built the weir too steep."
Mr Brian Sheerin, chief executive of the Southern Fisheries Board, who inspected the weir yesterday, said a fish pass in the weir to enable the salmon to pass through to spawn was built incorrectly and was too high for the fish.
Fisheries staff were working with engineers from the Department of the Marine and Natural Resources to design emergency measures, which would be put in place over the weekend, he said.
He was also due to meet the OPW, which built the weir, to discuss rebuilding the fish pass.
In a statement last night the OPW said if any alterations to the fish pass or weir were found to be necessary they would be carried out, provided they did not impair the efficient functioning of the flood defence scheme.
Mr Sheerin said he believed the number of salmon affected was not as high as originally feared. He inspected the weir by boat yesterday, with staff from the Department of the Marine, to establish the exact cause of the blockage.
He said he will also be asking staff to investigate a report that 20 dead fish were found at the Pococke River downstream from the weir yesterday morning.
Mr McGuinness said small numbers of fish all along the river had died from exhaustion in their failed attempts to get through the weir.
Local people have been gathering at the Lacken Weir in Kilkenny city to watch the wild Irish salmon returning from off the coast of Greenland. They are returning to spawn in the upper Nore where they were born.
A recent scientific report raised concerns about the low levels of salmon in the Nore, and has recommended a ban on all salmon fishing along the river next year. Some 10,000 fish are expected to be caught over the season this year.