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Marine Habitat Classification

Description of biotope or habitat type

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   Anemones, including Corynactis viridis, crustose sponges and colonial ascidians on very exposed or wave surged vertical infralittoral 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
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m, 20-30 m
Other Features Wave surged vertical rock; in surge gullies and caves.

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 IR.FIR.SG.CrSpAsAn Anemones, including <I>Corynactis viridis</I>, crustose sponges and colonial ascidians on very exposed or wave surged vertical infralittoral 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.


Vertical very exposed and exposed bedrock gullies, tunnels and cave entrances subject to wave-surge dominated by sponge crusts such as Clathrina coriacea, Myxilla incrustans, Pachymatisma johnstonia and Halichondria panicea and anthozoans such as Cylista elegans, Urticina felina, Alcyonium digitatum, Corynactis viridis and dwarf Metridium senile generally dominate the area; the anthozoans often appearing to protrude through the sponge layer. There may be dense aggregations of the hydroid Tubularia indivisa, the cup coral Caryophyllia smithii and the colonial ascidians Botrylloides leachii and Polyclinum aurantium. There may be a short crisiid turf, interspersed with Cradoscrupocellaria reptans. Encrusting coralline algae may occur on well-illuminated rock faces. The echinoderms Asterias rubens, Marthasterias glacialis, Echinus esculentus, Antedon bifida and Ophiothrix fragilis, the topshell Calliostona zizphinum and the calcareous tubeworm Spirobranchus triqueter may also be present on the rock face. The crabs Cancer pagurus and Necora puber may also be recorded. Due to the wave-surged nature and vertical orientation of these biotopes, kelps are rare and certainly never dominate.


No situation data available.

Temporal variation


Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Corynactis viridis 14 Common 81-100%
Alcyonium digitatum 5 Occasional 61-80%
Cylista elegans 5 Frequent 61-80%
Asterias rubens 4 Occasional 61-80%
Calliostoma zizyphinum 4 Occasional 61-80%
Metridium senile 4 Frequent 41-60%
Tubularia indivisa 4 Frequent 61-80%
Corallinaceae 3 Frequent 41-60%
Bryozoa indet crusts 3 Frequent 41-60%
Cancer pagurus 3 Occasional 61-80%
Clathrina coriacea 3 Occasional 61-80%
Pachymatisma johnstonia 3 Occasional 21-40%
Botrylloides leachii 2 Occasional 41-60%
Caryophyllia smithii 2 Occasional 41-60%
Crisiidae 2 Frequent 41-60%
Didemnidae 2 Frequent 21-40%
Myxilla incrustans 2 Frequent 41-60%
Porifera indet crusts 2 Frequent 41-60%
Cradoscrupocellaria reptans 2 Common 41-60%
Echinus esculentus 2 Occasional 41-60%
Antedon bifida 1 Occasional 41-60%
Halichondria panicea 1 Frequent 41-60%
Marthasterias glacialis 1 Occasional 41-60%
Necora puber 1 Occasional 41-60%
Ophiothrix fragilis 1 Occasional 21-40%
Polyclinum aurantium 1 Frequent 41-60%
Spirobranchus triqueter 1 Occasional 21-40%
Urticina felina 1 Occasional 41-60%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
1996 (6.95) ELR.BPat.Lpyg

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