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Marine Habitat Classification

Description of biotope or habitat type

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   Mixed faunal turf communities

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed, Moderately exposed
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn)
Substratum Bedrock, boulders
Zone Circalittoral - lower, Circalittoral - upper
Depth Band 5-10 m, 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.HCR.XFa Mixed faunal turf communities

  • 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 wave-exposed circalittoral bedrock and boulders, subject to tidal streams ranging from strong to moderately strong. This complex is characterised by its diverse range of hydroids (Halecium halecinum, Nemertesia antennina and Nemertesia ramosa), bryozoans (Alcyonidium diaphanum, Flustra foliacea, Bugulina flabellata and Crisularia plumosa) and sponges (Sycon ciliatum, Pachymatisma johnstonia, Cliona celeta, Raspailia ramosa, Amphilectus fucorum, Hemimycale columella and Dysidea fragilis) forming an often dense, mixed faunal turf. Other species found within this complex are Alcyonium digitatum, Urticina felina, Cylista elegans, Actinothoe sphyrodeta, Caryophyllia smithii, Spirobranchus triqueter, Balanus crenatus, Cancer pagurus, Necora puber, Asterias rubens, Echinus esculentus and Clavelina lepadiformis. Nine biotopes have been identified within this complex: ByErSp, FluCoAs, FluHocu, CvirCri, SwiLgAs, Mol, SubCriTf, SpNemAdia and SpAnVt.


No situation data available.

Temporal variation

No temporal variation data available.

Characterising species

Taxon Typical abundance - SACFOR scale % of core records where taxon was recorded
Actinothoe sphyrodeta Occasional 41-60%
Alcyonidium diaphanum Frequent 61-80%
Alcyonium digitatum Frequent 81-100%
Amphilectus fucorum Occasional 41-60%
Asterias rubens Frequent 81-100%
Balanus crenatus Frequent 41-60%
Bugulina flabellata Occasional 41-60%
Calliostoma zizyphinum Occasional 41-60%
Cancer pagurus Occasional 41-60%
Caryophyllia smithii Frequent 41-60%
Clavelina lepadiformis Occasional 41-60%
Cliona celata Occasional 61-80%
Crisularia plumosa Frequent 41-60%
Cylista elegans Occasional 41-60%
Dysidea fragilis Occasional 41-60%
Echinus esculentus Occasional 41-60%
Flustra foliacea Frequent 61-80%
Halecium halecinum Occasional 41-60%
Hemimycale columella Occasional 41-60%
Necora puber Occasional 41-60%
Nemertesia antennina Frequent 61-80%
Nemertesia ramosa Occasional 41-60%
Pachymatisma johnstonia Occasional 41-60%
Raspailia ramosa Occasional 41-60%
Spirobranchus triqueter Occasional 41-60%
Sycon ciliatum Occasional 41-60%
Urticina felina Occasional 41-60%

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.XFa

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