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Providing evidence to improve practice

Action: Asian clams: Clean equipment Control of Freshwater Invasive Species

Key messages

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  • A study in Portugal found that mechanical removal and regular cleaning of industrial pipes or addition of a sand filter were effective methods of permanently removing or reducing numbers of Asian clams, respectively.


Supporting evidence from individual studies


A study conducted in 1980-2010 at a power station and drinking water treatment plant in Portugal (Rosa et al. 2011) found that subjecting structures infested by the Asian clam Corbicula fluminea to cleaning, maintenance and sand filtration prevented or reduced re-infestation. At the power station, cleaning and maintenance procedures completely removed clam populations from the bypass channel of the power station and prevented re-infestation. At the treatment plant, installation of a multilayer sand-filter downstream from the raw water reservoir significantly reduced the amount of Asian clams passing through into the waterworks. Of the facilities managers interviewed, three out of 420 drinking water plants and two out of six power plants provided details on clam control. Managers were interviewed about past or current occurrence of clam infestation episodes, the types of structures affected, interventions in place and their degree of success. Interventions included mechanically removing and washing out clams, shortening the period between filter maintenance and regularly replacing sand in the multilayer sand filter.

Referenced papers

Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2019) Some aspects of control of freshwater invasive species. Pages 569-602 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.