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CR.HCR.XFa.CvirCri
Corynactis viridis and a mixed turf of crisiids, Bugula, Scrupocellaria, and Cellaria on moderately tide-swept exposed circalittoral rock

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Very exposed, Exposed, Moderately exposed 
 Tidal streams: Strong (3-6 kn), Moderately strong (1-3 kn) 
 Substratum: Bedrock; very large boulders 
 Zone: Circalittoral - lower, Circalittoral - upper 
 Depth Band: 10-20 m, 20-30 m 
 Other Features: Often on vertical or steep rock 

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.

Previous code

This biotope occurred in previous versions of the classification as:
CR.ECR.EFa.CorCri - Version: 97.06

Distribution of habitat CR.HCR.XFa.CvirCri  Corynactis viridis and a mixed turf of crisiids, Bugula, Scrupocellaria, and Cellaria on moderately tide-swept exposed circalittoral rock
Distribution of habitat CR.HCR.XFa.CvirCri Corynactis viridis and a mixed turf of crisiids, Bugula, Scrupocellaria, and Cellaria on moderately tide-swept exposed circalittoral rock, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

This biotope typically occurs on wave-exposed, vertical or steep, circalittoral bedrock or large boulders, usually subject to moderate or strong tidal streams. It is characterised by dense aggregations of the anemone Corynactis viridis and the cup coral Caryophyllia smithii intermixed with a short bryozoan turf of one or more Crisia spp., Scrupocellaria spp., Bugula spp. and Cellaria spp. Occasionally, this turf obscures the underlying C. virdis and C. smithii. Cushion and encrusting sponges, particularly Pachymatisma johnstonia, Cliona celata, Esperiopsis fucorum and Dysidea fragilis, are present in moderate amounts at many sites. The axinellid sponges Stelligera spp. and Raspailia spp. are less frequently recorded. Clumps of large hydroids such as Nemertesia antennina and Nemertesia ramosa as well as the soft coral Alcyonium digitatum and the bryozoan Alcyonidium diaphanum may be found covering the hard substratum. The anemones Actinothoe sphyrodeta and Sagartia elegans are typically present in low numbers, while the hard `coral' Pentapora foliacea is also occasionally observed. The most frequently recorded echinoderms are Marthasterias glacialis and Asterias rubens, although other species such as Echinus esculentus may also be seen. The rocky substratum may have a patchy covering of encrusting red seaweeds/algae. The crabs Necora puber and Cancer pagurus may be seen in crevices or under overhangs. This biotope is regularly recorded around south west England and Wales, often on vertical rock faces.

Situation

Due to its wave-exposed nature, kelp park and forest biotopes (LhypR and Ala) are commonly found in the infralittoral zone shallower than this biotope, and feature species such as Laminaria hyperborea, Sacchoriza polyschides and Alaria esculenta.

Temporal variation

Not known.

Similar biotopes

CR.HCR.XFa.ByErSp.SagThis variant is found on slightly less exposed coasts and in slightly weaker tides than CvirCri. In addition, ByErSp.Sag is characterised by a greater diversity of sponges, hydroids and anemones and also has small amounts of polyclinid ascidians, which in CvirCri are rare. ByErSp.Sag may sometimes be found below CvirCri.
CR.MCR.EcCr.CarSp.PenPcomThis variant is subject to weaker tides than CvirCri, but is found on similar wave-exposed upward-facing bedrock. The general appearance of CarSp.PenPcom is of a fairly sparse but diverse fauna and it lacks the bryozoan turf of CvirCri, having larger amounts of brittle and encrusting bryozoans such as Porella compressa and Parasmittina trispinosa.
CR.HCR.XFa.ByErSp.EunThis variant occurs under similar conditions as CvirCri. It is characterised by the presence of Eunicella verrucosa and Alcyonium glomeratum, in combination with diverse sponges and hydroids. It also contains a much wider range of ascidians than CvirCri.
CR.HCR.XFa.ByErSp.DysActThis sub-biotope occurs on similar wave-exposed bedrock and boulders as CvirCri, but is found in slightly stronger tidal streams. The sponge D. fragilis and the anemone A. sphyrodeta are present in much higher abundances than in CvirCri. A more diverse range of ascidians is present in ByErSp.DysAct.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Porifera O 1
Pachymatisma johnstonia O 2
Cliona celata O 5
Esperiopsis fucorum O 1
Raspailia ramosa O 1
Dysidea fragilis O 2
Nemertesia antennina C 3
Nemertesia ramosa O 2
Alcyonium digitatum C 10
Sagartia elegans O 1
Actinothoe sphyrodeta O 3
Corynactis viridis C 9
Caryophyllia smithii F 8
Cancer pagurus R 1
Necora puber O 2
Bryozoa F 3
Crisiidae C 4
Alcyonidium diaphanum O 2
Scrupocellaria C 1
Cellaria sinuosa F 1
Pentapora foliacea O 2
Asterias rubens F 4
Marthasterias glacialis F 4
Echinus esculentus O 2
Corallinaceae O 1

Example photographs of biotope


Dense corynactis on steep rock, Top of Hand Deeps reef, Plymouth., Paul Brazier, © JNCC Sloping bedrock ridges covered by Corynactis, W of Wagland Reef, Coverack., Eleanor Murray, © JNCC Dense corynactis on steep bedrock, Near Seals Rock, East coast of Lundy, Keith Hiscock, © JNCC
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Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901