02 February 2010 - Zebra Mussels invade Lough Bresk

The Zebra Mussel, an Invasive Alien Species, has been found for the first time at Lough Bresk, Co Fermanagh. NIEA officials confirmed the finding after it was reported by concerned local anglers.

Invasive Alien Species are organisms from abroad which establish themselves in local habitats and damage native species by out-competing with them for food, preying on them, altering their habitat or by introducing disease.

Zebra Mussels, native to the lakes of southeast Russia, attach themselves on the stony lake bottom but also to any hard surface, such as boats, buoys and water intake pipes, where they form very dense clusters and are principally spread via recreational water use. The first sighting in Northern Ireland was in 1994 at Lough Erne and they have since been reported in Lough Neagh.

The Government’s Zebra Mussel Control group has warned that they can cause blockages in intake pipes which increases costs to both water treatment plants and to boat users.

Zebra Mussel’s have significantly altered 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, excessive weed growth in Lough Erne, as a result of zebra mussels, has caused serious problems for boat users and has affected the tourism trade.

Bob Davidson of NIEA, who chairs the Zebra Mussel Control Group, said: "It is important that water users are aware of the impacts of Zebra Mussels. Impacts that have been recorded at Lough Erne emphasise the importance of preventing them from spreading to other lakes. Prevention of spread is an issue of shared responsibility and we are asking all water users to follow the guidance issued.

“Unfortunately Zebra Mussels have spread to a number of unconnected lakes since their first arrival in the Erne system in 1994. 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, as the anglers did in this case."

Guidance and advice on preventing the spread of the zebra mussel is on the Northern Ireland Environment Agency’s website

Notes to editors:

1. Species that have been introduced to a place where they do not naturally occur are known as 'non-native species'. Many of these live happily in the UK and Ireland without causing problems but a few become what are called 'invasive species'. These upset the balance of the ecosystem as they are commonly bigger, faster-growing and more aggressive than 'native species'.
2. Commonly invasive species have no natural predators to control their numbers. The native species are often unable to compete and quickly the ‘invasive species’ takes over.
3. ‘Invasive species can alter ecological relationships among native species. They can affect the whole ecosystem function, economic value of ecosystems and human health.
4. Whilst the majority of introduced species pose neither economic nor ecological problems, a few species become invasive and damaging to their new habitat.
5. Invasive species can be spread in many ways. Introductions can be either accidental or intentional. Many invasive plant species have been spread through deliberate introductions as the species was perceived to have a value in agriculture or ornamental gardening. However, many have also been unintentional introductions, either through planting of impure seed mixes that contain the invasive species, or by hitching a ride on a vehicle or in cargo.
6. The zebra mussel is a 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.
7. 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 and the fish populations have started to change. 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.
8. In November 2005, Zebra Mussels were discovered in Lough Neagh. A PhD student at Queen's University Belfast is currently researching their growth and impact on the Lough.
9. 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.
10. Alien species invasions are the second biggest threat to native biodiversity after habitat destruction and the zebra mussel is ranked among the worlds' 100 worst invasive species.
11. Zebra mussels first invaded Ireland in 1994 and spread rapidly throughout the Shannon-Erne waterway and connected navigable waters.
12. Zebra mussels can change fish populations by colonising spawning grounds and changing the populations of animals which fish eat. Research in other lakes has found a reduction in mid-water species and a shift towards bottom-dwelling species. The most common way of spreading zebra mussels is through recreational water activities such as boating and angling. Zebra mussels attach to boat hulls and movement of infested boats and equipment by water users is of great concern.
13. NIEA has issued guidance to water users on preventing spread of zebra mussels. Boats and equipment should be carefully cleaned, bilge water drained and any plant material attached to the engine or trailer should be removed.
14. Further information on invasive species can be found at www.invasivespeciesireland.com
15. 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.