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Marine Habitat Classification

Description of biotope or habitat type

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   Ostrea edulis beds on shallow sublittoral muddy mixed sediment

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Sandy mud with some shells and occasionally gravel
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Distribution of habitat SS.SMx.IMx.Ost <I>Ostrea edulis</I> beds on shallow sublittoral muddy mixed sediment

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.


Dense beds of the oyster Ostrea edulis can occur on muddy fine sand or sandy mud mixed sediments. There may be considerable quantities of dead oyster shell making up a substantial portion of the substratum. The clumps of dead shells and oysters can support large numbers of Ascidiella aspersa and Ascidiella scabra. Sponges such as Halichondria bowerbanki may also be present. Several conspicuously large polychaetes, such as Chaetopterus variopedatus and terebellids, as well as additional suspension-feeding polychaetes such as Myxicola infundibulum and Sabella pavonina may be important in distinguishing this biotope, whilst the Opisthobranch Philine aperta may also be frequent in some areas. A turf of seaweeds such as Plocamium cartilagineum, Nitophyllum punctatum and Spyridia filamentosa may also be present. This biotope description may need expansion to account for oyster beds in England.


No situation data available.

Temporal variation

No temporal data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Cliona celata 1 Occasional 41-60 %
Halichondria bowerbanki 4 Occasional 61-80 %
Esperiopsis fucorum 3 Occasional 41-60 %
Chaetopterus variopedatus 5 Occasional 81-100 %
Terebellidae 4 Frequent 41-60 %
Myxicola infundibulum 4 Frequent 41-60 %
Sabella pavonina 5 Common 41-60 %
Pomatoceros triqueter 1 Occasional 41-60 %
Balanus crenatus 1 Occasional 41-60 %
Pagurus bernhardus 5 Occasional 61-80 %
Philine aperta 2 Frequent 41-60 %
Ostrea edulis 16 Common 81-100 %
Aplidium punctum 4 Occasional 61-80 %
Ascidiella aspersa 8 Frequent 61-80 %
Ascidiella scabra 3 Frequent 41-60 %
Corallinaceae 1 Frequent 41-60 %
Plocamium cartilagineum 5 Frequent 61-80 %
Lomentaria clavellosa 1 Rare 41-60 %
Compsothamnion thuyoides 1 Occasional 41-60 %
Spyridia filamentosa 4 Frequent 41-60 %
Nitophyllum punctatum 3 Occasional 41-60 %
Polysiphonia elongata 1 Occasional 41-60 %
Dictyota dichotoma 2 Occasional 41-60 %
Laminaria saccharina 2 Rare 41-60 %

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
97.06 IMX.Ost

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