Invasive plant choking Lough Corrib

THE FUTURE of the State’s second-largest lake, Lough Corrib, is threatened by an invasive plant sold in garden centres, the Central…

THE FUTURE of the State’s second-largest lake, Lough Corrib, is threatened by an invasive plant sold in garden centres, the Central Fisheries Board has warned.

Failure to act this year to curb the spread of the “curly-leaved” waterweed, Lagarosiphon major, will lead to destruction of freshwater habitats, flooding and a virtual end to angling and other lake-based tourism activities, Dr Ciarán Byrne, newly appointed chief executive of the board has said.

“If there isn’t action very quickly we will be saying Corrib RIP,” Dr Joe Caffrey, a scientist with the board, said yesterday.

“Left to spread, it will have an enormous impact on watercourses throughout the State,” Dr Caffrey added.

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Ironically, an EU Life programme allocation of €1.4 million to fund research here into the pondweed’s rapid propagation cannot be spent due to the embargo on recruitment in State agencies.

Two scientists who were working on the project had to be let go last week due to the embargo and there is concern that the research grant-aid may have to be returned to the EU.

In addition, State expenditure of €600,000 last year to tackle the weed will have been wasted if measures to contain and ultimately remove the weed are not made an immediate priority, Dr Greg Forde, Western Regional Fisheries Board chief executive, said.

Dr Byrne, Dr Forde and Dr Caffrey outlined the full impact of the situation on a visit to lough Corrib yesterday.

Native to southern Africa, Lagarosiphon major was first detected growing in Lough Corrib in 2005.

The waterweed grows in water up to six metres deep, forms a virtual canopy in lakes, rivers, streams, canals and ponds, and spreads by fragmentation.

Such is its density that swans were sighted nesting on it last year.

Colonised areas are prime sites for perch and roach spawning.

This puts further pressure on the brown trout and salmon fishery for which Lough Corrib is famous worldwide.

Stem fragments of the plant are dispersed by wind, by boat movements, angling equipment and possibly wildfowl, according to the CFB, which is providing scientific research support to the WRFB.

Lorna Siggins

Lorna Siggins

Lorna Siggins is the former western and marine correspondent of The Irish Times