Lough Neagh system restocking is called into question by study

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A new high-level study of Lough Neagh brown trout questions the wisdom of restocking in certain circumstances.

A report on the population structure and genetic stock identification of Lough Neagh brown trout by QUB, Beaufort PhD student Kevin Keenan, Professor Paulo Prodohi and AFBI’s Drs Walter Crozier, Robert Rosell, Denis Ensing and Richard Kennedy says: “The presence of detectable patterns of population substructuring within the Ballinderry river is of particular interest given its known stocking history. The expectation, given this history, would be for lower levels of population genetic substructuring, (i.e. genetic homogenisation)

“The existence of clear patterns of population structuring within the system, questions the efficiency and validity of stocking within the system.

“Considering the high levels and geographical patterns of population restructuring and the likelihood that these differences are potentially associated with important adaptive traits, movement of individuals between populations should be limited and/or closely monitored.”

The authors of the report warned: “Unregulated movement of brown trout individuals within the Lough Neagh subsystem without consideration for the genetic patterns identified within the study, which are linked both to evolutionary history (i.e. colonisation history after the retreat of ice following the last glacial maximum) and natural selection could potentially lead to the breakdown of naturally occurring adaptive and spatial differences, thus resulting in the loss of biodiversity unique in Northern Ireland.

“Future stocking programmes in Lough Neagh should fully consider the information from this present study and have clear and well defined objectives to prevent biodiversity loss. Other less impacting approaches for assisting local trout populations including habitat and water quality improvements should be considered.

“There is no genetic evidence to suggest that dollaghan trout comprise a distinct genetic lineage. Dollaghan trout are common in the Six Mile Water and the River Main catchments which are genetically distinct.”

Those of a political bent might have swivelled their eyeballs when they read an earlier reference to the thorny subject of partition. But I hasten to add the reference was to piscatorial partition and not to the orange or green variety.

The report said one of its main findings was the presence of a clear geographical pattern in the way groups (mainly Six Mile, Main and Blackwater) were partitioned (i.e. a south-west to north-east gradient of increasing genetic divergence.

It said that in spite of the known history of stocking activities within and among catchments, which immediately leads to genetic homogenisation, results of the study indicated the existence of significant levels of population genetic structuring of brown trout populations inhabiting the main catchment rivers of Lough Neagh.

In 2011, Loughs Agency, Queen’s University and the University of Glasgow came together to develop a project to improve our understanding of aquatic habitats and resources. Supported by an award from SEUPB via the EU INTERREG IVA programme, the IBIS project was developed.

A major aspect was delivery of quality research to improve the evidence base upon which good management is built. Seventy years of research has been accumulated through 35 students each undertaking one-three years of research. 

John Pollock, Chief Executive of Loughs Agency said “this research will inform Loughs Agency’s freshwater and marine management tools to ensure the exploitation of resources of the Foyle and Carlingford aquatic ecosystems are managed and sustainable.  Congratulations to the IBIS team and the researchers on the high quality and innovative work they have undertaken.” 

Pat Colgan, Chief Executive of SEUPB said: “I applaud the work which the IBIS team have done in assisting environmentally sustainable economic development and I am confident that their valuable research findings will have a positive impact on environmental policy and the protection of our marine life in the future.”

Meanwhile, in the Cork Blackwater Hugh Hardiman caught a fresh seven pounder on fly on Carrig and his fishing partner Mat Burbridge released a nine pounder caught on spinner. On Monday three rods fishing in difficult conditions with strong winds and heavy, isolated showers had no luck.

The Irish Angling update said the Mayfly was well up in places and very patchy in others. Two sea trout of 6lb and 4lb were caught on the River Bandon and one of 5lb was caught on Lough Currane.

A new record salmon of 20lb 11 oz was recorded on the Rock Pool at Delphi on a Garry Dog tube fly. Salmon fishing on the River Moy continued to improve with 83 recorded and the middle to upper sections fishing best.

The River Drowes fished well in the first two weeks of May with 30 salmon accounted for. Fishing was difficult at times on Lough Sheelin but was excellent at others with buzzers taking many good trout up to 6lb 8oz. Hatches of Mayfly were fairly patchy on Lough Corrib but anglers were catching good trout on buzzer and olive patterns.

Good hatches of Olives with a sprinkling of Mayfly, along with some good hatches of buzzers helped anglers to catch plenty of trout on Lough Mask. It was another good week on Lough Arrow with some fish coming to the dap. Good catches of sonaghan were reported from Lough Melvin.

The close season has started for bass angling all around Ireland and it will remain closed until June 15.

At Craigmore, strong cold winds failed to keep the fish down as almost everyone who put on a black dry fly of any description was catching fish with some big numbers getting caught.

Gordon Wilson had 58 to 5lb on mixed dry flies and Maurice Anderson had trout to 4lb 10oz on nomads and f flies. Sandy Doreen had 31 to 7lb and Ian Fleming had 26 to 5lb on bloodworm and lures. Marti Allen had 25 to 4lb 10oz on dries and John Brown had 20 by the same method.

Other catches were: John Hughes, 23; Tommy Spence, 25 to 5lb; Martin McKenna, 20 to 5lb; Billy Hazlett, 18; Jeff Davidson 12 to 6lb; Paul Wilson, 15; Jim Magill, 19 to 5lb.

Billy Magill, 17 to 8lb; Martin McKillop, 17 to 5lb including a tagged fish worth £25; Thomas Taylor, Philip Neill and Neill Gray, 12; Martin Foster, 16 to 8lb including a tagged fish; Davy Couples, 15; Michael Booth, 12 to 5lb; Keith Henry, 18; Sammy McCaugherty, 11; Paul Armstrong, brown trout; Quentin McCurdy, 6lb; Sharon McCurdy, 5lb; Mark Wylie,7lb; Alan Walker, two at 5lb; Jim Quinn, 4lb; Fred Wilson,4lb; Davy Stitt, two at 4lb; Jim Simpson, three at 4lb.

At Cashel trout fishery conditions were ideal at the weekend when brothers Danny and Liam Morrin, Derry, had 15 trout using daddies and buzzers.

Andrew Logan, Dungiven, released seven trout which took small nymphs and Maurice Whiteman, Ardmore, accompanied by Paul McFadden and Keith Harkin, released 12 trout which fell to small dry fly patters. Jim Russell and Danny Walker Monkstown and Newtownabbey, each had two for home and released six on the Peter Ross wet fly. Paul Ford, Derry, caught two trout on a small suspender.