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Marine Habitat Classification

Description of biotope or habitat type

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   Caryophyllia smithii and sponges with Pentapora foliacea, Porella compressa and crustose communities on wave-exposed circalittoral rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed, Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock, boulders
Zone Circalittoral
Depth Band 10-20 m, 20-30 m, 30-50 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.EcCr.CarSp.PenPcom <I>Caryophyllia smithii</I> and sponges with <I>Pentapora foliacea</I>, <I>Porella compressa</I> and crustose communities on wave-exposed 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 variant is typically found on the upper faces and vertical sides of wave-exposed bedrock or boulders subject to moderately strong to weak tidal streams. The fauna is often sparse with the frequently observed Echinus esculentus giving it a grazed appearance, but the community may also be affected by violent storm action working into deep water during winter storms. Despite this spartan appearance, the community is relatively diverse and contains a wide range of sponges, hydroids, bryozoans and echinoderms. This variant is found on open coasts or offshore, and is characterised by the cup-coral Caryophyllia smithii, Alcyonium digitatum, the sea urchin Echinus esculentus, large specimens of the sponge Cliona celata, encrusting bryozoans and encrusting red algae. Although this variant tends to occur in deep water (depth range of 20-30m), a high degree of water clarity allows some red algae to grow at these depths. Other species recorded include large specimens of Haliclona viscosa, the bryozoans Parasmittina trispinosa, Porella compressa and Pentapora foliacea, the sea cucumbers Holothuria (Panningothuria) forskali and Aslia lefevrei and sparse hydroids such as Abietinaria abietina, Nemertesia antennina, Nemertesia ramosa and Halecium halecinum. Anemones such as Corynactis viridis, Cylista elegans and Urticina felina are also frequently seen. Various other species characteristic of wave-exposed rock include the sponges Pachymatisma johnstonia, Stelligera stuposa, the starfish Luidia ciliaris, Marthasterias glacialis, Asterias rubens, Henricia oculata, the crinoid Antedon bifida, the barnacle Balanus crenatus, the top shell Calliostoma zizyphinum and the polychaete Spirobranchus triqueter. The majority of the records within this variant originate from the west coast of Ireland.


Exposed kelp forest and park biotopes such as LhypR with species such as Laminaria hyperborea are typically found shallower than this biotope. Deeper, this biotope is believed to graduate into PhaAxi (deep erect sponges), as both these biotopes are common around the west coast of Ireland.

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
Caryophyllia smithii 10 Common 81-100%
Alcyonium digitatum 6 Frequent 81-100%
Cliona celata 6 Frequent 81-100%
Echinus esculentus 6 Occasional 81-100%
Corynactis viridis 5 Frequent 61-80%
Luidia ciliaris 4 Occasional 61-80%
Marthasterias glacialis 4 Occasional 81-100%
Parasmittina trispinosa 4 Frequent 61-80%
Asterias rubens 3 Occasional 61-80%
Calliostoma zizyphinum 3 Occasional 61-80%
Haliclona viscosa 3 Occasional 61-80%
Holothuria (Panningothuria) forskali 3 Frequent 61-80%
Nemertesia antennina 3 Occasional 61-80%
Corallinaceae 2 Frequent 41-60%
Abietinaria abietina 2 Frequent 41-60%
Aslia lefevrei 2 Occasional 41-60%
Henricia oculata 2 Occasional 61-80%
Pachymatisma johnstonia 2 Occasional 41-60%
Urticina felina 2 Occasional 41-60%
Antedon bifida 1 Frequent 41-60%
Balanus crenatus 1 Occasional 41-60%
Halecium halecinum 1 Occasional 41-60%
Nemertesia ramosa 1 Occasional 41-60%
Spirobranchus triqueter 1 Occasional 41-60%
Porella compressa 1 Occasional 41-60%
Cylista elegans 1 Occasional 41-60%
Stelligera stuposa 1 Occasional 41-60%

Similar biotopes or habitat types

This biotope occurs in slightly more sheltered shallower sites with stronger tidal streams. However, they are both found on similar substratum. CR.MCR.EcCr.FaAlCr has a much less diverse, impoverished fauna than CR.MCR.EcCr.CarSp.PenPcom possibly due to grazing pressure from E. esculentus. CR.MCR.EcCr.CarSp.PenPcom also has a more diverse range of sponges, hydroids and bryozoans.

This biotope occurs on similar wave-exposed upward-facing bedrock subject to stronger tides than CR.MCR.EcCr.CarSp.PenPcom. The characterising feature of CR.HCR.XFa.CvirCri are dense aggregations of jewel anemones C. viridis and cup corals C. smithii with an underlying crisiid turf. CR.MCR.EcCr.CarSp.PenPcom has larger amounts of brittle and encrusting bryozoans such as P. compressa, P. foliacea and P. trispinosa.

This biotope occurs on similar substratum in similar exposed conditions as CR.MCR.EcCr.CarSp.PenPcom, but is subject to stronger tidal streams and occurs only on upper-facing substratum. It is characterised by the abundant Ophiothrix fragilis and common Ophiocomina nigra, and there is typically a lower abundance of C. smithii.

This biotope occurs under similar conditions as CR.MCR.EcCr.CarSp.PenPcom, although it tends to be found at significantly deeper depths. Although high abundances of C. smithii are recorded in this biotope, CR.HCR.DpSp.PhaAxi has a much more diverse sponge fauna, especially erect sponges.

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