First discovery of population of Quagga mussel in Ireland

The National Biodiversity Data Centre has issued an Invasive Species Alert for Quagga mussel (Dreissena rostriformis bugensis) in Ireland.

As this is also a potential threat to catchments in Northern Ireland, DAERA have upgraded the Potential status on the Invasive Species Ireland website to Established and also added to their Species Alerts 

DAERA will also be promoting the CHECK CLEAN DRY campaign on all their managed water bodies and as widely to all public water users as possible.

The Quagga mussel has been found in both Lough Ree (abundant over a wide range of depths) and Lough Derg, and is also present in the Shannon river between these two lakes. This first discovery of Quagga mussel in Ireland was detected in early summer 2021, with surveillance ongoing at this time – July 2021.
It has not been recorded in Northern Ireland but the Shannon-Erne waterway provides a direct route for spread.

© John Boldt, CC BY-NC 4.0.
© Gavin Noyes, CC BY-NC 4.0.

Potential impacts:

        • due to its filtering capacity and ability to produce dense populations it can alter whole freshwater ecosystems, reducing native plant, invertebrate and fish populations
        • it can have significant economic impacts, e.g. when growing in pipes of water treatment plants and hull fouling

The Quagga mussel has a wide ecological tolerance, is suited to Irish climatic conditions and has the ability to survive on both muddy and hard substrate e.g. stones, shells, wooden posts, hulls, concrete; therefore it is likely that its distribution will increase. Unlike zebra mussel it can become established on finer sediments and as a result may have a much greater impact (compared to zebra mussel) on soft or muddy lakes, e.g. Lough Neagh.

Field signs:

        • Quagga mussel occupy lakes, rivers and estuarine habitats
        • as adults attach to hard substrata, they may also be seen on rocks, native mussel shells, timber, hulls of boats, pipes or other man-made structures in the water
        • they typically occur in freshwater but can also be found in estuarine areas
        • when established Quagga mussel can occur in high densities
        • a thin shell and a high breakup rate can result in large quantities of dead shell washing up on the edge of an affected water body

Preventing spread:

        • Quagga mussel is likely to be spread by boats to the upper Shannon and through the Shannon-Erne Waterway to the Erne
        • it could also be spread overland by trailered craft – owners of boats should be made aware they could spread this species from the Shannon to other water bodies if they don’t follow strict biosecurity protocols
        • anglers and other water users could unintentionally carry it on their equipment from infested water bodies to new ones
        • following the Check Clean Dry guidance is the most effective way to help prevent further spread and introduction to new sites
        • natural dispersal is most likely to occur in the infested waterbody/catchment


Invasive Species Ireland

Invasive Species Ireland