Fears of invasive species spreading to River Corrib system


Galway City Council has issued a warning about the invasive Quagga Mussel, and the need to prevent it spreading to the Corrib.

The invasive species has been discovered in the River Shannon catchment, including Lough Derg, and the 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 1 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 assess as having a potential high impact as an invasive species.

National Biodiversity Data Centre advice on the species is available at: biodiversityireland.ie/quagga-mussel-alert/.

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.