The Asian clam (Corbicula fluminea) in the River Thames, London, England

The Asian Clam, Corbicula fluminea (Muller, 1774) invaded British waters in 1998. It remained confined to an isolated network or rivers in Eastern Britain until 2004, when it was discovered in low densities in the River Thames, London. We report that C. fluminea has now been discovered at three more sites on the tidal River Thames. Surveys indicate that the clam has now established dense populations of up to 648±352 m -2 at Ham on the River Thames, with evidence of annual recruitment. Given the substantial connectedness of the Thames to many of Britain’s other rivers, it is likely that C. fluminea will now continue to spread through Britain’s waterways.