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Marine Habitat Classification

Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Offshore circalittoral coarse sediment

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Gravel and coarse sand.
Zone Circalittoral
Depth Band 20-30 m, 30-50 m, 50-100 m
Other Features

Biotope origin

Derived using data from Various
Faunal group Infauna

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.SCS.OCS Offshore circalittoral coarse 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.


Offshore (deep) circalittoral habitats with coarse sands and gravel or shell. This habitat may cover large areas of the offshore continental shelf although there is relatively little quantitative data available. Such habitats are quite diverse compared to shallower versions of this habitat and generally characterised by robust infaunal polychaete and bivalve species. Animal communities in this habitat are closely related to offshore mixed sediments and in some areas settlement of Modiolus modiolus larvae may occur and consequently these habitats may occasionally have large numbers of juvenile M. modiolus. In areas where the mussels reach maturity their byssus threads bind the sediment together, increasing stability and allowing an increased deposition of silt leading to the development of the biotope SS.SBR.SMus.ModMx.


No situation data available.

Temporal variation

No temporal data available.

Characterising species

Characterising species data not applicable.

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code Habitat name
2015 (15.03) SS.SCS.OCS Offshore circalittoral coarse sediment
2004 (04.05) SS.SCS.OCS Offshore circalittoral coarse sediment
1997 (97.06) Part of SS.COS Circalittoral offshore sediments

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