Blow to African weed

ANGLING NOTES: I RECEIVED the following e-mail from my good friend Peter Powell, whose book, The Sound of Many Waters , I reviewed…

ANGLING NOTES:I RECEIVED the following e-mail from my good friend Peter Powell, whose book, The Sound of Many Waters, I reviewed some years back. Peter from Athboy, Co Meath, has had a life-long love affair with fishing.

“We have just returned from our annual mayfly visit to Lough Corrib, and had some great fishing, including trout of 5lb 8oz and 4lb 7oz. Hatches of mayfly were much stronger than usual, including a prodigious hatch on May 24th which would have done credit to Sheelin or Derg on a good day – wonderful to see.

“However, perhaps you might share with your readers the good news about Corrib, and celebrate a hugely significant success on the part of the Central Fisheries Board (CFB) and the Western Regional Fisheries Board (WRFB) who jointly set up a programme to tackle the problem of Lagarosiphon major in the lake.

“The invasive African curly leafed water weed appeared in Rinerroon Bay on upper Corrib in 2005, and rapidly took over this magnificent and highly productive bay.

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“By May 2008 it was impossible to either fish part of this 50-acre bay, or drive a boat through the dense weed. It had also established itself in 120 other sites around the upper and middle lake.

“The future looked bleak and we wondered how the spread of the weed could be prevented, as it reproduces readily on fragmentation, and can exist in water up to 20 foot deep. A really nasty customer.

“But lo and behold! This year Rinerroon Bay is clear of the weed again, back to its old fishing greatness, and we as a group were enormously impressed with the transformation.

“We felt that the highest commendation and gratitude were due to the CFB and WRFB for the meticulous way the problem was tackled, and that this should not go unrecognised. So, well done to all concerned.

“Apparently, several methods of control are in place, the most important being mechanical cutting by a custom-designed boat, guided to locations by GPS, and recovery and removal to a remote safe location for destruction.

“This is best done in winter when the weed floats when cut, whereas trials showed that it just flops over in summer and is impossible to recover. Also, a roll-out jute geo-textile is used to smother the weed and this allows the native weed species to grow safely through.

“Additionally, hand-cutting by scuba divers is employed in rocky areas inaccessible to the cutter or jute blanket, and tests are continuing on a non-toxic herbivore that might prove vital in the future.

“In the long term it’s not known if the weed can be eliminated, but while removal continues in the infected areas of the lake, research is concentrating on the life-cycle of Lagarosiphon to establish possible weaknesses that might be exploited.

“Scientists in South Africa and New Zealand, where the weed is also a problem, are helping our researchers.

“Well done to the CFB and WRFB for their painstaking approach to this threat to Corrib and for assistance from UCD, QUB and GMIT in research and sampling. And thanks also to the National Parks and Wildlife Service, Office of Public Works, Western River Basin District and Galway City Council, for providing the vital funding.

“It is great to salute a landmark success, the importance of which should not go unrecognised, and let’s hope that the support and funding is forthcoming to allow this vital work to continue.”

* The Irish Ladies Fly Fishing Association is hosting the 21st International Competition on Loch Lein, Killarney, Co Kerry, this Thursday. Teams from England, Wales, Scotland and Ireland are taking part.

* I regret to report the recent passing of Des McDonnell. For more than 20 years he contributed to Angling Newsand Irish Anglers Digestunder the pseudonym of Jassid.

He was a member of the Dodder Anglers and founder member of Irish Fly Tyers’ Club, and a great supporter of Dublin Angling Initiative (DAI). In recent years he gave fly-tying lessons to youngsters in the Whitechurch Youth Development.

Des is survived by his wife and best friend Ina, and sons Philip and Marcus. May he rest in peace.

angling@irishtimes.com