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Marine Habitat Classification

Description of biotope or habitat type

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   Cushion sponges, hydroids and ascidians on turbid tide-swept sheltered circalittoral rock

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Bedrock, boulders
Zone Circalittoral
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 CR.MCR.CFaVS.CuSpH.As Cushion sponges, hydroids and ascidians on turbid tide-swept sheltered circalittoral 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 sub-biotope typically occurs in a mixture of turbid, full and variable salinity water, on wave-sheltered and moderately exposed bedrock or boulders. Tidal streams are typically moderately strong but may vary considerably. This sub-biotope occurs in relatively shallow water (typically 5m to 11m water depth) and is dominated by cushion sponges, hydroids and ascidians. On the silty, rocky substrata, large growths of sponge are usually associated with this biotope (Suberites ficus, Hymeniacidon perlevis, Cliona celata, Halichondria panicea, Raspailia ramosa). The tasselled form of Amphilectus fucorum is also notably present. Other epifauna present includes silty hydroids such as Nemertesia antennina, Nemertesia ramosa, Plumularia setacea, Hydrallmania falcata and Halecium halecinum. Individual colonies of dead mans fingers Alcyonium digitatum and plumose anemones Metridium senile may be seen attached to the tops of boulders and ridges. At some sites, whole sides of rocks may be colonised by the anemones Cylista elegans, Sagartia troglodytes and Actinothoe sphyrodeta. Within crevices in the rocky substratum and at the base of boulders Urticina felina and Cereus pedunculatus may be found. Ascidians such as Clavelina lepadiformis, Morchellium argus, Dendrodoa grossularia, Diplosoma listerianum and Distomus variolosus may all be observed. Other ubiquitous species which may be recorded include Polydora, terebellid worms, Balanus crenatus, Alcyonidium diaphanum and Asterias rubens.


No situation data available.

Temporal variation

Not known.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Suberites ficus 10 Frequent 81-100%
Nemertesia antennina 7 Frequent 61-80%
Clavelina lepadiformis 5 Occasional 61-80%
Hymeniacidon perlevis 5 Occasional 61-80%
Morchellium argus 4 Occasional 61-80%
Alcyonium digitatum 3 Occasional 41-60%
Cliona celata 3 Occasional 61-80%
Halichondria panicea 3 Frequent 41-60%
Metridium senile 3 Frequent 41-60%
Nemertesia ramosa 3 Occasional 41-60%
Plumularia setacea 3 Occasional 41-60%
Urticina felina 3 Frequent 41-60%
Actinothoe sphyrodeta 2 Occasional 41-60%
Balanus crenatus 2 Frequent 21-40%
Cereus pedunculatus 2 Occasional 41-60%
Dendrodoa grossularia 2 Frequent 41-60%
Amphilectus fucorum 2 Frequent 41-60%
Polydora 2 Common 41-60%
Seraphsidae 2 Frequent 41-60%
Alcyonidium diaphanum 1 Occasional 21-40%
Asterias rubens 1 Occasional 41-60%
Diplosoma listerianum 1 Rare 41-60%
Distomus variolosus 1 Frequent 21-40%
Halecium halecinum 1 Occasional 41-60%
Hydrallmania falcata 1 Occasional 41-60%
Raspailia ramosa 1 Occasional 41-60%
Cylista elegans 1 Occasional 41-60%
Sagartia troglodytes 1 Frequent 21-40%

Similar biotopes or habitat types

This biotope occurs on reduced salinity circalittoral bedrock and boulders subject to strong to weak tidal streams. Verylimited species diversity, unlike CR.MCR.CFaVS.CuSpH.As.

This biotope is closely related to CR.MCR.CFaVS.CuSpH.As, but tends to be found in areas that experience less stable, lower salinity seawater. CR.MCR.CFaVS.CuSpH.As has a more diverse range of sponges, hydroids and bryozoans than CR.MCR.CFaVS.CuSpH.VS.

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