Mussel in Derg could have high impact
Fears have been expressed that an invasive mussel found in Lough Derg could spread to lakes such as Lough Corrib in the west of the country.
The Quagga Mussel found in Lough Derg and Lough Ree has been classed as an invasive species that could have a high impact on water courses where it establishes. Galway City Council has issued a warning about the invasive mussel and the need to prevent it spreading to the Corrib.
The warning coincides with a call by Inland Fisheries Ireland, which has asked users of the River Shannon and its tributaries to take action to halt the proliferation of non-native species that may cling to boats and spread to other waters.
IFI is recommending that anglers, and motorised and non-motorised watercraft owners/users, do not move boats or craft from the Shannon, and its lakes, tributaries and interconnected canals to other water bodies.
The Quagga Mussel has been discovered in the River Shannon catchment, including Lough Derg, and Galway City Council has warned about the importance of trying to block it from spreading to the River Corrib system.
Angling and water sports have been identified as key risk activities for potentially spreading the mussel.
The city council summarised the potential impacts of allowing the Quagga Mussel to spread:
“Quagga mussel is a filter feeder removing planktonic organisms from the water column. It has a high filtration rate likely to result in further changes to water quality and nutrient dynamics of, in particular, lakes.
“The Quagga Mussel is likely to compete with native mussel species and with the alien invasive Zebra Mussel (Dreissena polymorpha).
“The presence of the Quagga Mussel is likely to lead to a further surge in fouling, including of man-made structures in the water, of boats and water craft.
“It may have additional impacts on water quality and the ecological integrity of Irish aquatic ecosystems. In invaded areas, it can significantly reduce native plant, invertebrate and fish populations.
“Having a wide ecological tolerance and suited to Irish climatic conditions, it is expected to become widely distributed in time.
“It appears to have a preference for cooler water and can settle on finer sediments than the Zebra Mussel, explaining its greater abundance at depth in some colonised lakes elsewhere. It can produce up to one million eggs per year.”
Indigenous to the Dnieper River in Ukraine, the Quagga Mussel has been steadily progressing across Europe since the early 2000s.
In Ireland it was first discovered in Lough Derg and Lough Ree in the early summer of 2021, and is assessed as having a potential high impact as an invasive species.
Further advice for anglers, boaters, and other water users on how to minimise the risk of spreading an invasive species is available at: invasives.ie/check-clean-dry-resources.
Meanwhile, Chairperson of the Angling Council of Ireland Martin McEnroe says the invasive mussel species has now been sighted across a number of Irish lakes.
He says the means by which it has spread to Ireland are still unknown, but he believes the most likely scenario is that boats from countries like France and Italy are coming to the River Shannon to cruise for long periods of time.