Alien species invades Lough MacNean

Boat owners were today warned of the economic and ecological dangers of Zebra Mussels after a new discovery at Lough MacNean, Co Fermanagh.

Adult Zebra mussels, an Invasive Alien Species, were found attached to the shell of a native mussel during monitoring by the Northern Ireland Environment Agency (NIEA) on Lower Lough MacNean.

The Government’s Zebra Mussel Control Group has warned that Zebra mussels can cause blocked intake pipes, which increases costs to both water treatment plants and to boat users. They also warn of the threat they pose to the natural functioning of a lake system.

John Early, of the NIEA and The Zebra Mussel Control Group, said: “Zebra mussels, native to the lakes of south east Russia, attach themselves on the stony lake bottom but also to any hard surface, such as boats, buoys and water intake pipes, where they can form very dense clusters and are principally spread by recreational water use.

"It is important that water users are aware of the environmental impacts of Zebra mussels. The impacts that have been recorded at Lough Erne emphasise the importance of preventing them from spreading to other unconnected lakes. Prevention of spread is an issue of shared responsibility and we are asking all water users to follow the guidance issued.

"Signage has been placed at slipways around Lough Erne and at Lough MacNean highlighting that boats and equipment should be carefully cleaned, bilge water drained and any plant material attached to the engine or trailer should be removed.

“I would encourage water users to be aware of their presence and if they do find them outside the Lough Erne and Lough Neagh system to report them to NIEA. Reports of all invasive species, including Zebra mussels, can be made through the ‘Alien Watch’ section of the invasivespeciesireland website

Zebra mussels filter water resulting in improved clarity, as a result of the clearer water there have been changes to fish communities in Lough Erne and hence are a major risk to the future of some freshwater fisheries. This may result in a decline in income to commercial fisheries and to the recreational tourist industry.

Additionally, the improved water clarity has resulted in excessive growth of native aquatic plants in Lough Erne. This excessive growth of aquatic plants has caused serious problems for recreational water users and has affected the tourism trade.

Guidance and advice on preventing the spread of the zebra mussel is available on the NIEA website .

Notes to editors:

1. Invasive Alien Species are organisms from abroad which establish themselves in local habitats where they can damage native species by out-competing with them for food, predating on them, altering their habitat or by introducing disease.
2. The Zebra mussel is a small stripy, freshwater mussel native to the Caspian Sea area of eastern Europe. They form large colonies that attach to almost any hard surface and have already affected private and public water abstraction stations on Lough Erne, resulting in modifications at the Killyhevlin Water Treatment Plant costing over £100,000.
3. Lower Lough MacNean is a large freshwater lake in County Fermanagh. The lake is fed by a small river which flows from Upper Lough MacNean into the lough at a bridging point between the villages of Belcoo and Blacklion, County Cavan. The river forms the border between County Fermanagh and County Cavan in the Republic of Ireland.
4. The Zebra mussel invasion of Lough Erne has altered nutrient cycling, increased water clarity, reduced the abundance of phytoplankton - the basis of the food chain. As a result the fish populations have changed. One of the most noticeable impacts has been on the native Swan mussel whose populations became extinct. Similar impacts have been reported for Lough Derg, Lough Key and Lough Ree.
5. In November 2005, Zebra Mussels were discovered in Lough Neagh.In December 2009, Zebra Mussels were discovered at Lough Bresk, County Fermanagh. They are also known to occur in Lough Carron near Derrygonnelly, Co.Fermanagh.
6. The Zebra Mussel Control Group consists of representatives from NIEA (DOE), Agri-food and Biosciences Institute (AFBI), Northern Ireland Water, Inland Fisheries (DCAL), Waterways Ireland, Queens University Belfast and the National Parks and Wildlife Service (DOEHLG). The group aims to co-ordinate raising awareness among water users with the aim of preventing the further spread of zebra mussels.
7. Media enquiries should be directed to the DOE Press Office on 028 9054 0003. Out of office hours, please contact the duty press officer on pager 07699 715 440 and your call will be returned.