New invading mussel in Lough Derg

A new invasive mussel has been discovered in the River Shannon system, including in Lough Derg.

The Quagga Mussel, originally from Ukraine, was discovered in large numbers earlier this month in Lough Ree by a team from UDC led by Dr Jan Robert Baars. It has been found in smaller numbers in Lough Derg, where it is expected that numbers will increase.

The discovery in Lough Derg resulted from the co-operation of the Lough Derg Science Group, its co-founder Dr Dan Minchin having worked on the project with Dr Baars on the Shannon since 2016

This species, Dreissena Rostriformis Bugensis, commonly known as the Quagga Mussel, is expected to expand and supress the numbers of the closely-related Zebra Mussel that arrived in Ireland in 1994.

It is thought the Zebra Mussel arrived as fouling on imported leisure craft ferried from the Midlands of Britain. It is not known how the Quagga Mussel arrived in Ireland, but may also have been with fouled craft. The Zebra Mussel looks very similar to the invader, with which it can be easily confused.

The Quagga Mussel is an aggressive invader. In other areas in Europe and in North America where it was introduced, it appears to have a preference for cooler water conditions, explaining its occurrence in deeper water. Together with its capability of living over silty bottoms, this is likely to lead to an increase in biomass in the deeper regions of lakes, and so further modify the ecology of deep-water bodies such as lakes and reservoirs.

This mussel is also capable of spawning over a wider range of temperatures than the Zebra Mussel, which increases the risk of the fouling of pipework used for abstracting water.

The climatic conditions in Ireland are suitable for this new species to expand further. While currently restricted from Lough Ree southwards in the Shannon River, it is expected to spread to the northern Shannon, and through the Shannon-Erne Waterway to the Erne, through the fouling on boats.

It is also expected to spread to other water bodies with the overland transmission of trailered boats, as has already happened with the spread of the Zebra Mussel.

There are no known practical ways of eliminating either the Quagga or Zebra Mussel, except using local treatment methods and practices preventing it from spreading elsewhere. Anyone moving boats from the Shannon should be aware that they could spread this species