Quagga mussel in the Thames


So by now you will have heard about quagga mussel (Dreissena rostriformis bugensis) and its arrival in the United Kingdom. For those who haven’t here is a summary of the key information.

The original population was found in a tributary of the River Colne by Environment Agency ecologists and confirmed on the 1st October 2014 by Dr David Aldridge of Cambridge University. Since then these further populations have been identified:

West of London:

  • Wraysbury Reservoir
  • Queen Mother Reservoir
  • Queen Elizabeth II / Bessbourough Reservoirs, and
  • Queen Mary Reservoir

North of London:

  • Warwick East Reservoir
  • Warwick West Reservoir, and
  • William Girling Reservoir

A population has also been identified in the Thames at Richmond, firmly confirming their presence in London.

The arrival of the quagga mussel has been anticipated for a number of years and is similar to the already present zebra mussel (Dreissena polymorpha).

Why is this a problem?

Quagga mussels are a major concern as they:

  • Are prolific biofoulers, meaning that they able to clog up pipes and other underwater structures which is a considerable concern to those in various water industries.
  • Have increased filtering capacity, which results in an altering of the whole freshwater ecosystem.
  • Can changes algal diversity which can increase the chance of algal blooms.
  • Can be a direct threat to other native slower growing mussels who can be smothered by the faster growing quagga mussels.

What now?

LISI held a workshop in November at London Zoo (Zoological Society of London) with key stakeholders to raise awareness of quagga mussel and to raise awareness of appropriate biosecurity options. As no effective removal or eradication method is known for quagga once established in open river systems, the best method of slowing the spread is carrying out effective biosecurity. This should be done in line with the Check, Clean, Dry method.

  1. Check your equipment and clothing for live organisms – particularly in areas that are damp or hard to inspect.
  2. Clean and wash all equipment, footwear and clothing thoroughly. Research has found that washing with warm water can increase the effectiveness of this step.
  3. Dry all equipment and clothing – some species can live for many days in moist conditions. And make sure you don’t transfer water elsewhere.

More considered biosecurity may be required for some people and organisations and further information on biosecurity planning can be found here.

LISI is able to provide Check Clean Dry posters, stickers and ID booklets to partners to encourage better biosecurity throughout London so do get in touch if you would like information about these resources.

Identification and Reporting:

It can be very difficult to tell the quagga and zebra mussels apart, so it is advised to refer to the identification sheets which can be downloaded from the Great Britain Non-Native Species Secretariat. If you suspect you have found some quagga mussels please take some pictures of the key identification features (on the ID sheet above) and send them to alertnonnative@ceh.ac.uk.

If you would like any further information on quagga mussels or other invasive non-native species please do get in touch with us at LISI