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Displaying items by tag: mollusc

#INLAND WATERWAYS - Trial dredging operations to curtail the spread of Asian clams at designated sites in the lower River Barrow are set to conclude today.

Inland Fisheries Ireland (IFI) employed the use of a a traditional cockle harvesting boat to physically remove the clams from the river bed, in an effort to explore methods of controlling or eradicating what it describes as an "ecosystem-changing invader" in other infested waters.

IFI scientists supervised the trials, using teams of divers to quantify the result of the dredging efforts.

The Asian clam (Corbicula fluminea) is "a most unwelcome addition to the fauna of the lower River Barrow". The bivalve mollusc is regarded as "one of the most notorious aquatic invasive species in the world".

First recorded in the river downstream of St Mullin’s in April 2010, subsequent IFI studies have revealed that the Asian clam is firmly established in the lower Barrow and in the River Nore downstream of Inistioge. Populations have also been recorded in the River Shannon and in Lough Derg.

In one section of the River Barrow the clam has achieved a "staggering" density of almost 10,000 per square metre.

Dr Joe Caffrey, senior scientist with IFI, said of the trial dregding: “It is imperative that every effort is made to control the expansion and spread of this highly adept invasive species.

"The results from these trials will inform future national management plans for this most unwelcome non-native species and will, at the very least, dramatically reduce the numbers of individuals in the test sites.

He added: "In tandem with these trials, research effort is being focused at producing other control methods that can be targeted as this species.”

Published in Inland Waterways

Irish Sailing Classes and Association – There’s no shortage of one-design classes from which to choose and each gives its enthusiasts great competition, fun and camaraderie, writes Graham Smith in this review of the classes. 

One-design racing is where it all starts. It is, after all, where all the top sailors earned their stripes, battling away for line honours without a thought for a handicapper’s calculator wiping away a hard-fought victory!

Indeed, you could count on less than one hand the number of top Irish sailors who didn’t cut their teeth in a one-design dinghy! Just think of Cudmore, Barrington, Watson, Wilkins, Hennessy and Dix to name a few and you realise that they honed their skills in everything from Enterprises to Lasers and a lot in between.

At present count, there are a little over 30 one-design classes in Ireland, split almost evenly between dinghies and keelboats, a statistic which might raise a few eyebrows. They range from the long-established Mermaids, IDRA14s and Dragons to the newer additions like Fevas, Topaz and RS Elite. They all fill a particular need and give their owners and crews considerable enjoyment.

Many have attracted their World or European Championships to Irish waters over the years and while 2009 is notable for a lack of such events here, the following year will see the Etchells Worlds at Howth and perhaps a few other international regattas too.

In addition to the review, we asked each class to complete a questionnaire giving details of their fleet numbers, whether they were on a growth pattern or holding their own, so we could highlight those ‘on the up’ and those remaining static in terms of numbers. The older traditional designs, as you might imagine, fall into the latter category, although that’s not a negative!

CLASS REVIEW  The State of the Classes – League Table (as at February 2009)

S = Static; U = Up/growing

275     Optimist   U

200+   Laser   S

189     Mermaid   S

160     Flying Fifteen   S

130     RS Feva   U

115     Shannon One Design    U

100+   Mirror   S

100+   Topper   U

99       Topaz   U

94       Laser SB3   U

87       GP14   U

85       Squib   S

70       Fireball   S

70       Ruffian   S

60       J24   S

60       Shipman   S

52       Dragon   S

50       RS400/200   S

50       420    U

43       Multihulls    U

42       Dragon    S

40       Water Wags    U

40       Wayfarer    S

34       IDRA14    U

33       Puppeteer    U

28       Etchells    S

27       E-Boat    U

26       Glen    S

25       Enterprise    S

18       Sigma 33    S

18       Howth 17    U

13       RS Elite    U