Inland Fisheries Ireland (IFI) chief executive Francis O’Donnell addressed the Oireachtas on Tuesday (13 February) on the State body’s programme to mitigate barriers to fish passage on Irish rivers.
“Migratory species such as Atlantic salmon, sea trout, sea lamprey, river lamprey, twaite and allis shad and European eel all make long migratory journeys to reproduce,” O’Donnell said. “However, a range of other fish, such as pike, brown trout and bream, live entirely in fresh water but make extended movements along the river system for feeding or to access spawning and nursery areas.
“Any restrictions to fish migrations may have negative consequences for their habitat use, reproductive or feeding capacity and could lead to long-term declines in their population.”
O’Donnell noted that barriers to fish passage run from “small structures such as bridge floors, culverts, sluices to larger structures such as weirs and dams”. These can impact on natural river processes, affecting temperature, flow rate and sediment transport.
IFI is mapping the extent of barriers nationwide, with more than 73,000 potential barriers identified and nearly half of these assessed.
“Of those assessed as a problem, 233 have had follow-up surveys…[which] are required before any mitigation work can be carried out,” O’Donnell said.
IFI’s National Barriers Programme (NBP), developed with the support of two Government departments, runs until 2027 with the aim of addressing water-quality pressures with mitigation works.
“The NBP has estimated that there are potentially 8,500 culverts/bridges, 1,500 weirs and 160 other structures in Irish rivers that represent a barrier to fish passage,” O’Donnell said. “Over the life of the NBP…it is expected that 257 barriers will be mitigated.”
IFI is currently working on improving fish passage at Bretts Weir on the River Nore in Co Kilkenny; Bakery Weir on the River Suir in Cahir, Co Tipperary; Pallas Weir on the River Bann; and the Dalligan Weir on the River Dalligan in Co Waterford.
Those pilot schemes are along with works at Annacotty Weir and Askeaton Weir in Co Limerick, Templederry Bridge in Co Tipperary, Castlecor Weir fish passage in Co Meath, and Bishops Stream in Co Roscommon.
In addition, O’Donnell said IFI is working with the likes of the ESB to understand the impacts of hydroelectricity on migrating salmon and eels, noting that “large barriers on the Erne, Liffey and Shannon systems have brought those populations to near extinction”.
O’Donnell concluded: “Unfortunately, the European eel numbers across Europe have been decimated and Atlantic salmon numbers returning to Ireland compared to the 1970s have been reduced by 80 per cent. The trend is getting worse and there is now a need to really deal with barriers and find solutions if we are going to save two wonders of nature that undertake what is a most amazing migratory journey in the natural world.”
