Biodiversity & Conservation

Macoma balthica and Abra alba in infralittoral muddy sand or mud


<i>%Macoma balthica%</i> and <i>%Abra alba%</i> in infralittoral muddy sand or mud
Distribution map

SS.IMS.FaMS.MacAbr recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland The IMS.MacAbr biotope is present in coastal inlets of south west Britain, patches through northern Irish Sea and patches throughout. Also present in the Southern Bight, North Sea and in the English Channel.
National importance Not available

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Near-shore shallow muddy sands and muds, and sometimes mixed sediments, may be characterized by the presence of the bivalve Macoma balthica and Abra alba. Lagis koreni and Donax vittatus may also be significant components although they may not necessarily all occur simultaneously. Fabulina fabula, Nephtys cirrosa, Echinocardium cordatum and Crangon crangon may also be present. The community is especially stable (Dewarumez et al., 1992). The substratum is typically rich in organic content and the community may occur in small patches or swathes in shallow waters parallel to the shore (Jones, 1950; Cabioch & Glaçon, 1975). This biotope is known to occur in patches between Denmark and the western English Channel. This community has been included in the 'Boreal Offshore Muddy Sand Association' of Jones (1950) and is also described by several other authors (Petersen, 1918; Cabioch & Glaçon, 1975). A similar community may occur in deep water in the Baltic (Thorson, 1957). This biotope may occur in slightly reduced salinity estuarine conditions where Mya sp. may become a significant member of the community (Thorson, 1957). Sites with IMS.MacAbr may give over to neighbouring Amphiura biotopes with time (E.I.S. Rees pers. comm. 1996). (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

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This review can be cited as follows:

Budd, G.C. 2007. Macoma balthica and Abra alba in infralittoral muddy sand or mud. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 30/11/2015]. Available from: <>