Alien mussels!

Alien Quagga Mussels discovered in England 

Top Invasive Non-Native Species discovered in the Thames

A species identified by the Government as one of the most destructive invasive non-native species has been found at Wraysbury Reservoir and in the nearby River Colne system, a tributary of the River Thames.  Known to alter whole freshwater ecosystems, a mature adult can filter one or more litres of water a day, feeding on zooplankton which is the base of the food chain that all fish need to survive on and produce 1 million eggs in one season, so they can spread very rapidly. 

Quagga mussels (scientific name Dreissena bugensis) originate from the Caspian and Black Sea region which is the same part of the world as the Killer Shrimp and the Demon Shrimp which both arrived in the UK over the last 4 years.  The rapid breeding of the Quagga results in large numbers being established very quickly and has caused extensive damage in the areas it has already reached; The Great Lakes, Mississippi & Ohio rivers in America, Main river in Germany, the Netherlands and the Volga river in Russia.  Quagga mussels also have an impact on water supply and sewage infrastructure, canal lock gates, boat propellors and any other hard surfaces. 

Quagga mussel (Dreissena bugensis)

Quagga mussel (Dreissena bugensis)

There are no known methods for eradicating mussels once they have got into waterbodies.  The Angling Trust has called for concerted action by government and its agencies to stop this damaging species spreading to other rivers by alerting all water users and urging them to follow the Check, Clean, Dry guidelines for biosecurity and to report all sightings on the GB NNSS website at

The EU Invasive Alien Species Regulation was approved finally by the European Council on Monday 29 September, which will require Member States to take action to prevent and eradicate invasive alien species of most concern.  The Angling Trust will be lobbying the UK government to ensure that these types of species are included in the lists.

Mark Owen, Head of Freshwater at the Angling Trust said: 'It’s vitally important that all water users, including anglers, take every possible precaution to stop this species spreading throughout the UK.  Quagga mussels could do untold damage to freshwater and estuarine environments if they are allowed to spread which could have a significant impact on marine and freshwater fish stocks.'