Biodiversity & Conservation

Ostrea edulis beds on shallow sublittoral muddy sediment



Image Bernard Picton - Ostrea edulis beds on shallow sublittoral muddy sediment. Image width ca 25 cm.
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Distribution map

SS.SMx.IMx.Ost recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

For a list of 2004 characterising species please see the JNCC website.

Species indicative of sensitivity

To assess the sensitivity of the biotope, the sensitivity of component species is reviewed. Those species that are considered to be particularly indicative of the sensitivity of the biotope, and for which research has been undertaken in detail are shown below (see selection criteria). The biology of other component species of the biotope is also taken into account wherever information is known to the researcher.

Species found especially in this biotope

  • Ostrea edulis
  • Ascidiella aspersa
Community Importance Species name Common Name
Key structural Ostrea edulis Native oyster


The native oyster forms beds providing substratum and interstices for a diversity of other organisms. Accumulation of shell material, faeces and pseudofaeces further modify and enrich the sediment. The other characterizing members of the biotope have a widespread distribution and take advantage of the substratum or stabilized sediment provided by the population of Ostrea edulis. The ascidian Ascidiella aspersa is commonly found on oyster beds but is generally regarded as a competitor with the oysters and is not restricted to this biotope. Therefore, only Ostrea edulis has been chosen to indicate the sensitivity of the biotope, as loss or damage to populations of the native oyster will affect the biotope as a whole.
In undertaking an assessment of sensitivity of this biotope, account is taken of knowledge of the biology of all characterizing species in the biotope. However, the selected 'indicative species' is particularly important in undertaking the assessment because it has been subject to detailed research.

Additional information

The MNCR recorded a total of 246 species within this biotope, although not all occurred in a single record. Studies of the fauna of native oyster have been reported for the Oosterschelde (Korringa, 1951), Scottish waters (Millar, 1961), Loch Ryan (Millar, 1963; Howson et al., 1994); and the Essex oyster beds (Mistakidis, 1951). Korringa (1951) listed over 250 species of epifauna on the shells of Ostrea edulis in the Oosterschelde.

This review can be cited as follows:

Tyler-Walters, H. 2001. Ostrea edulis beds on shallow sublittoral muddy sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 27/11/2015]. Available from: <>