Quagga mussels on the march in the UK (Image: David Aldridge, University of Cambridge)

The quagga mussel, which is native to eastern Europe, has been found in the UK, in the Wraysbury river near London’s Heathrow Airport. It has invaded rivers and lakes across Europe over the past 20 to 30 years and is now also reaching the US. We do not yet know how it got to the UK.

“It’s only in one place so far, but we have yet to check the River Thames and all its associated reservoirs,” says David Aldridge of the University of Cambridge. According to Aldridge, there are five major reasons why it creates havoc wherever it invades, plus one thing that could keep it in check.

It’s hugely invasive

The notorious zebra mussel has clogged up the Great Lakes in the US, but the quagga mussel is even more invasive and aggressive – so much so that it is even now displacing the zebras from their Great Lake strongholds.


It keeps bad company

The quagga mussel’s faeces provides food for other invasive organisms from its native lakes and rivers of eastern Europe, and the Black, Caspian and Azov seas. That includes so-called killer shrimp – dubbed the “pink peril” because they kill and eat most native shrimp wherever they invade. These co-evolved with the quagga and frequently co-invade with them, says Aldridge. They have spread across mainland Europe and have already reached the UK.

It shows no mercy

Quagga mussels literally suffocate other mussel species. They sit on their shells and physically push them into underlying silt or sediment. Native UK mussel species that could be at risk include depressed river mussel, Pseudanodonta complanata.

It gets very busy

At 5 centimetres long or less, quaggas are far from the largest mussel. But they breed incredibly fast, and can rapidly block pipes and other water inlets and outlets, costing the water industry millions to manage, usually by having to physically dislodge them.

It messes up the neighbourhood

The quagga mussel upsets ecosystems by filtering and cleaning water, allowing light to penetrate to the riverbed and nuisance weeds to grow and flourish in lakes and rivers.

…but we may have a secret weapon

There is no way to completely eradicate quagga mussels once they have settled into a river or reservoir. But there is one thing that may help keep them, plus zebra mussels, in check.

Aldridge and his colleagues have developed a “poison pill”, a capsule made from the same material that the mussels eat. Once inside the mussel’s stomach, the outer layers dissolve away, releasing salts that kill the molluscs.

“They swallow this poison pill, called a BioBullet, and that kills them straight away,” says Aldridge. “It contains a salt, and because quaggas have dilute body fluids, it comes as an osmotic shock that kills them.”

Aldridge says his Biobullet is designed to be harmless to other aquatic life, and that native mussel species seem to be more discerning and reject the pill. Biobullets have been successfully tested against zebra mussels in the UK and the Netherlands.

When this article was first published it rooted mussels in the wrong part of the taxonomic tree of life. This has now been corrected.