Asian clam

Corbicula fluminea


Photo credit: ©GBNNSS
Corbicula fluminea
  • Freshwater lakes and streams of all sizes with mud, silt, sand and gravel benthic substrate (The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers). 

  • Typically this bivalve grows up to 25 mm in length but larger forms are know which can grow up to 50 to 65 mm.
  • C. fluminea has a yellowish brown to black shell with concentric, evenly spaced ridges on the shell surface.
  • This species is hermaphroditic, and has a high level of reproduction.

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Origin and Distribution:
  • Originated in China, Korea, south-eastern Russia, and the Ussuri Basin. Now widespread in Europe and the United States.

  • Asian clam reaches high densities and colonises suitable substrates.
  • It has similar impacts to the zebra mussel, competing with other species for food and space.
  • Water based industries, such as hydroelectric power stations and water abstraction for household use may be faced with higher costs due to the clogging of intake pipes by this species.
  • In the US one estimate from 1980 put the costs of correcting this problem at an estimated 1 billion dollars annually (ISSG).
  • They can also negatively impact on sand/gravel abstraction.

Is it found in Northern Ireland?
  • C. fluminea is present Northern Ireland and Ireland.
  • It is now known to be present in the River Foyle, the River Shannon, Keeldra Lough (Leitrim), Lough Derg, The River Barrow and the River Nore.
  • More distribution information can be found on the NBN Atlas NI 

You can help by reporting any sightings: @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.

How did it get here?
  • C. fluminea could have been introduced to Northern Ireland in boat bilge water as live bait or as a result of escapes from the aquarium trade. C. fluminea are known as "pygmy" or "gold" clams in the aquarium trade.

For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email:


Species Related Files:

Invasive Species Northern Ireland

Invasive Species Northern Ireland