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Marine Habitat Classification

Description of biotope or habitat type

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   Circalittoral Sabellaria reefs (on rock)

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed
Tidal streams Moderately strong (1-3 kn)
Substratum Bedrock, boulders, cobbles, pebbles
Zone Circalittoral - lower
Depth Band 10-20 m, 20-30 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 CR.MCR.CSab Circalittoral <I>Sabellaria</I> reefs (on rock)

  • 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.


This biotope complex occurs on moderately wave-exposed, circalittoral bedrock, boulders and cobbles subject to moderately strong tidal streams. It is characterised by dense crusts of the polychaete Sabellaria spinulosa covering the substratum. Other fauna present in many cases reflects the biotopes found on nearby rock, so to a certain extent, is quite variable. Species typically present include the bryozoans Flustra foliacea, Alcyonidium diaphanum and Pentapora foliacea, the hydroid Nemertesia antennina, the sponges Tethya aurantium and Phorbas fictitius, the anemones Urticina felina and Cylista elegans, and the ascidians Distomus variolosus, Polycarpa pomaria and Polycarpa scuba. The barnacle Balanus crenatus, the polychetes Spirobranchus triqueter and Salmacina dysteri, the starfish Crossaster papposus, and Alcyonium digitatum may also be recorded. Two variants of the Sspi biotope have been identified: Sspi.ByB and Sspi.As (characterised by didemnid ascidians).


No situation data available.

Temporal variation

No temporal variation data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Sabellaria spinulosa 32 Common 81-100%
Didemnidae 10 Frequent 41-60%
Flustra foliacea 8 Occasional 61-80%
Asterias rubens 7 Occasional 61-80%
Urticina felina 5 Occasional 41-60%
Alcyonium digitatum 3 Frequent 21-40%
Distomus variolosus 3 Common 21-40%
Spirobranchus triqueter 3 Frequent 21-40%
Crossaster papposus 2 Occasional 21-40%
Pentapora foliacea 2 Occasional 21-40%
Polycarpa pomaria 2 Common 21-40%
Alcyonidium diaphanum 1 Occasional 21-40%
Balanus crenatus 1 Frequent 21-40%
Nemertesia antennina 1 Occasional 21-40%
Phorbas fictitius 1 Occasional 21-40%
Polycarpa scuba 1 Common 21-40%
Cylista elegans 1 Occasional 21-40%
Salmacina dysteri 1 Occasional 21-40%
Tethya aurantium 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
1997 (97.06) CR.MCR.CSab

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