‘Serious threat to our waterways’: First quagga mussel Found in Northern Ireland

Quagga Mussels (left) and Zebra Mussels (right) - (1.5x magnification)

The first confirmed case of the highly invasive quagga mussel in Northern Ireland has been detected in Lower Lough Erne, triggering alarm among environmental scientists, politicians and local communities who depend on the lough for livelihoods, recreation and drinking water.

The discovery has prompted sharp criticism of the Department of Agriculture, Environment and Rural Affairs (DAERA) from Fermanagh and South Tyrone Ulster Unionist Party MLA Diana Armstrong, who warned that the species poses a serious threat to fragile freshwater ecosystems and water quality across the region.

“I am shocked by the first confirmed case of the highly invasive Quagga Mussel in Lower Lough Erne. This is a serious threat to our ecosystems and water quality,” she said.

Ms Armstrong highlighted what she described as a lack of preparedness and oversight within the department, linking the latest discovery to wider concerns about invasive species management.

“It was only recently that Minister Muir confirmed to me he didn’t even know how many Zebra Mussels existed in Lough Neagh, now this. That lack of awareness and oversight speaks volumes about the failure to prioritise biosecurity.”

Lower Lough Erne is a vital natural asset for local communities, supporting tourism, angling, boating and wildlife, and fears are growing that the arrival of quagga mussels could have long-term ecological and economic consequences.

Unlike zebra mussels, quagga mussels can colonise deeper waters and softer substrates, allowing them to spread more widely and outcompete native and existing invasive species.

Ms Armstrong said the discovery exposed what she called a failure to put adequate safeguards in place.

“This alarming development highlights a complete failure by DAERA to implement robust biosecurity measures. The absence of guidance on power-washing facilities and effective regulation of watercraft movements is unacceptable and has left our waterways exposed.

“Our lakes and rivers are vital natural assets, and DAERA must urgently step up to protect them. Biosecurity must become a top priority before it’s too late.”

Scientific confirmation and spread risk

The presence of the quagga mussel (Dreissena rostriformis bugensis) was confirmed following routine surveys carried out by scientists from the Agri-Food and Biosciences Institute (AFBI).

Suspected samples collected from Lower Lough Erne were confirmed on 10 December after DNA analysis at Queen’s University Belfast.

Originally native to the Ponto-Caspian region around the Black and Caspian Seas, the quagga mussel has spread rapidly across Western Europe, North America and Mexico in recent decades. It was first recorded in Britain in 2014 and detected in the Shannon system, including Loughs Ree and Derg, in 2021.

Scientists warn that quagga mussels are particularly damaging due to their high filtration rates, which can drastically alter food webs, reduce nutrients available to native species and cause significant infrastructure fouling.

Dr Kevin Gallagher, Senior Scientific Officer at AFBI, said:

“The confirmation of quagga mussel in Lower Lough Erne is significant given the connectivity of major water bodies. Once established, this species can spread rapidly and cause substantial ecological and economic impacts, including altered food webs and infrastructure fouling. This underlines the need for enhanced surveillance across connected systems, including Lough Neagh, and strict biosecurity to limit further spread.”

With quagga mussels now confirmed in both the Shannon system and Lower Lough Erne, officials believe a connected invasion along the Shannon–Erne corridor is the most likely explanation.

It is considered plausible that the species may already be present, but undetected, in intermediate water bodies, including Upper Lough Erne.

Calls for vigilance and public action

DAERA Minister Andrew Muir described the discovery as another serious challenge for Northern Ireland’s freshwater environment.

“This confirmation that the highly invasive Quagga mussel has arrived in Northern Ireland represents another significant pressure to our already beleaguered freshwater system,” he said.

“Increased vigilance and surveillance is critical. My officials are engaging with stakeholders and public agencies to alert them to this arrival and the need for enhanced biosecurity measures. Cross-border engagement also continues through the Shared Island Biosecurity and Invasive Species Initiative.”

Officials have contacted key stakeholders and are planning additional monitoring to assess the extent of the population and identify other water bodies at risk, based on likely pathways of spread. These include recreational boating, angling, trailered craft and the transfer of equipment such as paddle boards and canoes between catchments.

Rose Muir from the Northern Ireland Environment Agency’s Invasive Non Native Species team warned that once established, eradication is not possible.

“There is no effective control or eradication method for quagga mussel once it has established in a water body. The best method of slowing the spread and reducing the risk to other water bodies is by applying better biosecurity through the Check, Clean, Dry approach. We are urging all water users to follow this protocol strictly when moving between water bodies.”

For communities around Lower Lough Erne, the discovery has heightened fears for the future health of the lough and the livelihoods tied to it, reinforcing calls for swift, coordinated action to prevent further spread across Northern Ireland’s interconnected waterways.