Advice issued to boaters and anglers







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More invasive mussels have been discovered in rivers and reservoirs near the Thames. Quagga Mussels have now been discovered at nine locations.

The Environment Agency has now added to earlier advice from two boating organisations urging boaters, anglers and walkers to help stop the mollusc's spread.

The quagga mussel has now been confirmed at the following locations.

To the west of London:

·         Wraysbury Reservoir
·         River Wraysbury
·         The Queen Mother Reservoir, Datchet
·         Queen Elizabeth II Reservoir, Walton-on-Thames
·         Queen Mary Reservoir, near Staines
·         Bessborough Reservoir, Walton-on-Thames

In the Lee Valley:
·       Warwick East and West Reservoirs, Walthamstow
         William Girling Reservoir, Enfield

The EA is working with other organisations including Thames Water, the Angling Trust and local angling clubs, to ensure that people check, clean and dry any equipment that has been in contact with water.

The quagga mussel can significantly affect freshwater ecosystems, and can outcompete native mussels. It can also block water pipes and smother boats’ hulls.

Sarah Chare, head of fisheries, at the Environment Agency, said: “These newest discoveries only go to show just how prolific the quagga mussel is. We are monitoring the extent of its spread and working closely with partners to ensure they are aware of it and know what action to take.

“Everyone has an important role to play by following the simple steps of ‘check, clean, dry’. If you spot one then please report it to us through the online form.”

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.  Invasive species 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.”

Quagga mussels tend to be about the size of a human thumbnail but can grow to about 4cm. The larvae of quagga mussels are not visible to the naked eye which makes drying a critical step in applying good biosecurity. There's good evidence that rinsing or soaking equipment in hot water increases the chance of killing larvae and adults, and is a suggested addition to the check, clean, dry approach.

Further details on the quagga mussel and advice on how to slow its spread can be found on the Non native Species Secretariat web pages:

Checking, cleaning and drying equipment after use is important not only to help slow the spread of this species, but also other invasive species that might be present in waterways. It is especially important to prevent the spread of invasive non-native species to isolated, vulnerable or protected sites. 

There is specific biosecurity guidance for different water users on the non-native species secretariat check, clean, dry pages.

If you think you may have found a Quagga Mussel, you can also send an email with a photograph and location details to: