Concern for NI waterways as invasive mussel detected

A highly invasive species of mussel which can cause extensive environmental damage to waterways has been detected in Northern Ireland for the first time.

The quagga mussel is a non-native mollusc from eastern Europe which breeds extremely quickly, often out-competing and replacing other mussels.

Quantities of quagga were collected during routine surveys in Lower Lough Erne and on 10 December the species was formally identified through DNA analysis.

Stormont's Agriculture and Environment Minister Andrew Muir said its detection is "another significant pressure to our already beleaguered freshwater system".

"Increased vigilance and surveillance is critical," the minister said in a statement.

"My officials are engaging with stakeholders and public agencies to alert them to this arrival and the need for enhanced biosecurity measures."

Quagga mussels are considered a costly environmental threat because they can affect water quality, disrupt ecosystems and clog up pipes.

They were first detected in the UK more than a decade ago and are also present in the Republic of Ireland, but this is the first confirmed detection in Northern Ireland, Daera said.

According to the UK Environment Agency the tiny creatures are usually the size of a thumbnail, but they can grow up to up to about 1.5 in (4cm).

An adult female can produce up to 1m eggs per year, making them prolific breeders, and their eggs are so small they are not visible to the naked eye.

Quagga mussels are similiar to zebra mussels - another non-native mollusc which has already extensively damaged Northern Ireland's biggest lake - Lough Neagh.

Both invasive species feed on microscopic organisms and while eating they can filter a litre or more of water each day.

This process of filtration makes the water clearer, which in turn can allow other species to grow and disrupt delicate habitats.

The zebra mussel is believed to have contributed to the conditions which has allowed potentially toxic blue-green algae to bloom in Lough Neagh.

Last year, more than 44,000 fish had to be culled at a fish farm in County Antrim due to the presence of zebra mussels, as the fish could not be used to stock waters.

Quagga mussels are capable of even higher water filtration rates than zebra mussels and they can also survive in a wider range of depths.

Daera said it expects quagga mussels will "eventually outcompete and displace" zebra mussels.

Daera added that it is "plausible that quagga are already present but undetected in intermediate water bodies, including Upper Lough Erne".

The Northern Ireland Environment Agency (NIEA) said there is "no effective control or eradication method for quagga mussel once it has established in a water body".

However, there are ways to slow the spread of the creatures and reduce the risk of them entering other waterways.

Rose Muir from NIEA's Invasive Non Native Species team said the best way to do this is through biosecurity measures known as the "check, clean, dry approach".

This involves asking all anglers and boaters to thoroughly clean any equipment before using any waterway.

"We are urging all water users to follow this protocol strictly when moving between water bodies," Ms Muir said.