This CAISIE project update comes on the day the Central Fisheries Board and the seven Regional Fisheries Boards are re-structured into a single organisation now known as Inland Fisheries Ireland (Iascach Intíre Éireann).
Research & control of Lagarosiphon major
Research on approaches to controlling the Lagarosiphon weed in Lough Corrib and the efficacy of these measures is continuing apace. Indeed, the CAISIE team has just got a scientific paper published in a leading international aquatic invasive species journal Aquatic Invasions about the novel approach being used to control this problematic weed (http://www.aquaticinvasions.net/2010/AI_2010_5_2_Caffrey_etal.pdf). The method employs an environmentally friendly biodegradable jute matting which additionally has been demonstrated to rehabilitate the previously extirpated native plant communities. Indeed, these plants are an important keystone habitat for the native macroinvertebrates and fish in the lake.
The distribution of the weed in Lough Corrib is being monitored as an ongoing concern. An extensive survey of the lower lake to assess whether it has become established has just been completed. Fortunately, no Lagarosiphon was found to be present, however, a number of habitat ‘hot spots’ were identified that are considered ideal for the weed to colonise. These areas will be monitored regularly in future to facilitate an early detection should the weed attempt to establish in this part of the lake.
The strategy to control the Lagarosiphon major infestation in the lake has shifted from mechanical cutting in the autumn to spring period to large-scale and small-scale jute matting application during the summer months. This is because the weed typically collapses in late spring reverting from its characteristic erect canopy forming phase.
The mechanical cutting of Rinnerroon Bay earlier this year has been very successful in locally controlling the Lagarosiphon infestation. A recent survey showed no significant re-growth to date. Before the cutting, this bay had become almost completely clogged up by the weed, inhibiting its use as a boating and angling amenity. The ongoing status of weed in the bay will be monitored going forward.
Education and awareness, and stakeholder engagement
We held a highly successful technical workshop in Athlone in April 2010 beside Lough Ree (this lake has recently been invaded by the bloody-red shrimp). The primary aim of this workshop was to further inform the development of the CAISIE project action plans. As well as the very informative presentations, many useful and interesting discussions were held throughout the day. Around 100 people attended this event including both national and international aquatic invasive species scientists and policymakers, staff from the relevant state agencies and other public bodies, and representatives of angling and boating federations.
This was followed by a public forum on aquatic invasive species held in Galway city at the end of April 2010. Members of the CAISIE project from the Central Fisheries Board as well as representatives of the Western Regional Fisheries Boards were on hand to inform the participants and answer questions on the latest research and control of Lagarosiphon major in Lough Corrib. In addition, aquatic invasive specimens were on display and this included Ireland’s new invasive species, the Asian clam, recently discovered in part of our other study area on the River Barrow system. Over 50 people attended this event including concerned members of the public, Galway city and county councillors, and local angling and boating federations. The feedback received was most valuable and this was added to by some excellent contributions from the audience.
Arising from this meeting, representations have just been made to Galway county council to reiterate the seriousness of the Lagarosiphon major infestation in Lough Corrib to impact on both current and future angling and recreational amenity use of the lake as well as the potential of the weed to contribute to significant flooding problems in the Corrib catchment should it become established in the lower lake.
On a lighter note, CAISIE held a demonstration stand for Fisheries Awareness Week and International Biodiversity Day at the Western Regional Fisheries Board HQ beside the salmon weir in Galway city in early May. It really was a fun day and the weather was superb. We met many interested members of the public and were encouraged by their knowledge on the topic of invasive species in Ireland. We showed them some of the problematic aquatic species that we now have in Ireland, including a preserved specimen of the Chinese mitten crab which was found in the lower Barrow estuary in 2008.
One of the roles of CAISIE is to promote the education and awareness of aquatic invasive species in Ireland. In addition to the above, we have had articles published in both local and national media outlets since the project commenced. These have included RTÉ’s EcoEye, TG4 nuacht, The Irish Times, The Examiner, The Connaught Tribune and Connaught Telegraph, Galway Independent and Galway Bay Fm among others. It was nice to see some underwater video footage we had taken of the Lagarosiphon weed with our digital camera shown on the TG4 nuacht!
What else?
The water level in Lough Corrib is now at its lowest since last October. Indeed, a local paper here in Galway reported last week that the River Corrib is now at its lowest level in 15 years. There is currently only one sluice gate open at the salmon weir in the city itself. Many shallows in the lake that are usually covered are now partly exposed. This includes the sighting of exposed boulders above the water line at the aptly named ‘long shallow’ in the middle of the southern part of the upper lake. This comes after the worst flooding in over 850 years which occurred back in November and the unusual prolonged cold snap in late winter which was the harshest since the early 1960s.
With the water levels so low, it certainly is awe-inspiring on a calm day when transversing the lake on the boat to the various fieldwork sites where you can see right down into the lake bottom and wonder about the large wild fish that grace these waters. Majestic Atlantic salmon and freshwater eels passing through, returning to the tributaries or out to sea, beautiful Lough Corrib brown trout and their ferox relatives, as well as specimen predatory pike. Sometimes we have looked up when sampling underwater, only to see one of these fish staring right at us for a moment before scampering off in an instant into the great abyss.
Some interesting finds in the lake while sampling recently include an old fyke net riddled with zebra mussels, freshwater sponges and charophyte plants and a fairly expensive fly fishing rod, complete with reel, line and fly. As it turned out the rod had fallen off a lake boat four days earlier, unbeknown where to its English owner, as he travelled in from a day’s fishing. Owner and the rod are now happily reunited.
The CAISIE project offices are now fully set up on the lake shore. Many thanks to the local staff of the Western Regional Fisheries Board and the FAS team who helped us get off the ground.
Lagarosiphon major at Bob’s Island © CAISIE
The growing crown of Lagarosiphon major © CAISIE
Jute matting application © Joe Caffrey
Native plant re-establishment on the jute matting at Ard Point © Joe Caffrey
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