Invasion of the killer mussels from Russia
Alien mussels from southern Russia, are invading fresh territory across Northern Ireland and their strongholds are our lakes and rivers.
The Northern Ireland Environment Agency has reported that the invasive zebra species, which comes originally from lakes in the Caspian Sea area, has now conquered Lough Bresk in Co Fermanagh, after local anglers raised the alert.
It’s the fourth scalp for this damaging species which first reached Northern Ireland in 1994 when it invaded Lough Erne and has gone on to establish populations in Lough Neagh and Carron Lough near Derrygonnelly in Co Fermanagh.
Many plants and animals from abroad have established themselves in Northern Ireland without causing too much disruption, but zebra mussels are classed among the world’s top 100 invasive species, meaning they establish themselves in local habitats and endanger native species by outcompeting with them for food, preying on them, altering their habitat or introducing disease.
Zebra mussels not only attach themselves to the stony lake bottom in large colonies, but can clog up any hard surface including boats, buoys and water intake pipes.
The Government's Zebra Mussel Control group has warned that the mussels can cause blockages in intake pipes which can mean costly damage to water treatment plants and boats.
The stripey freshwater mussel has already damaged private and public water abstraction stations on Lough Erne — in one case it cost more than £100,000 to modify the state-of-the-art Killyhevlin Water Treatment Plant after the mussels made their presence felt.
They are also capable of causing sweeping changes to waterways and according to NIEA have already significantly altered fish communities in Lough Erne, threatening the future of some freshwater fisheries.
This could result in declining incomes to commercial fisheries and the recreational tourism industry.
The animals have altered nutrient cycling, increased water clarity, reduced phytoplankton which form the basis of the food chains and changed fish populations by colonising spawning grounds and changing the populations of species that are prey to fish.
One of the worst effects has been on the native swan mussels whose populations in Lough Erne, Lough Derg, Lough Key and Lough Ree have been driven to extinction.
Bob Davidson of the 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 in Northern Ireland.”
NIEA has issued guidance to water users on preventing the spread of zebra mussels by carefully cleaning boats and equipment, draining bilge water and removing any plant material attached to the engine or trailer.
More information is available on NIEA’s website.