Scientists have warned that the recent discovery of the Quagga mussel in the UK may be just the tip of the iceberg, with at least four other invasive species from the Ponto-Caspian region likely already present undetected. The Quagga mussel, found in the River Wraysbury on 1 October, is part of a group of freshwater species spreading westward from south-east Europe, posing a serious threat to native wildlife and infrastructure.
A study by the University of Cambridge modelled the likelihood of 23 Ponto-Caspian species arriving in the UK, focusing on five already present, including the demon shrimp and killer shrimp. Their models suggest that four additional species, such as the predatory shrimps Echinogammarus ischnus and Limnomysis benedeni, are likely already in Britain but undetected. These shrimps prey on native species, including insect larvae and fish eggs, and could significantly alter ecosystems.
Dr David Aldridge, co-author of the study, explained that the first wave of invaders, including the Quagga mussel, can facilitate further invasions. For example, the killer shrimp thrives alongside the zebra mussel, feeding on its waste and hiding among its shells. The Quagga mussel itself is a major concern, as it can smother native mussels, filter out algae, and clog water pipes, causing economic damage to power plants and irrigation systems.
The invaders are most likely to arrive via ships from the Netherlands, which has 14 of the 23 species established and is a major trading partner with the UK. The south-east of England is particularly at risk. Aldridge emphasised that while it is not too late to contain the Quagga mussel, urgent action is needed to prevent further invasions. “Unless we do something dramatic to change the UK’s biosecurity strategy, these things will come,” he said, calling for policy changes to stop the spread.
