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CR.HCR.XFa.ByErSp
Bryozoan turf and erect sponges on tide-swept circalittoral rock

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Habitat (physical) description

Distribution

 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; boulder 
 Zone: Circalittoral - lower, Circalittoral - upper 
 Depth Band: 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.ByErSp  Bryozoan turf and erect sponges on tide-swept circalittoral rock
Distribution of habitat CR.HCR.XFa.ByErSp Bryozoan turf and erect sponges on tide-swept 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 is typically found on wave-exposed circalittoral bedrock or boulders subject to tidal streams ranging from moderately strong to strong. It often has a thin layer of silt covering the seabed, and is characterised by a bryozoan/hydroid turf with erect sponges. Typical bryozoans to be found include crisiids, Alcyonidium diaphanum, Flustra foliacea, Pentapora foliacea, Bugula plumosa and Bugula flabellata, while typical hydroids include Nemertesia antennina, Nemertesia ramosa and Halecium halecinum. The soft coral Alcyonium digitatum is frequently recorded on the tops of boulders and rocky outcrops. Characteristic erect sponges include Raspailia ramosa, Stelligera stuposa and Stelligera rigida; other sponges present include Cliona celata, Dysidea fragilis, Pachymatisma johnstonia, Polymastia boletiformis, Hemimycale columella, Esperiopsis fucorum, Polymastia mamillaris and Tethya aurantium. Other species present include Caryophylia smithii, Actinothoe sphyrodeta, Corynactis viridis, Urticina felina, Balanus crenatus, Asterias rubens, Marthasterias glacialis, Henricia oculata, Echinus esculentus, Clavelina lepadiformis, Calliostoma zizyphinum and Necora puber. Three variants of this biotope have been described, but all are characterised by a bryozoan turf with erect sponges. ByErSp.Eun is found primarily on circalittoral bedrock and is dominated by the seafan Eunicella verrucosa. ByErSp.DysAct is found under slightly stronger tide-swept conditions, and is characterised particularly by the sponge D. fragilis and the anemone A. sphyrodeta. Finally ByErSp.Sag is characterised by the anemone Sagartia elegans.

Situation

No situation data available.

Temporal variation

No temporal variation data available.

Similar biotopes

Not applicable or unknown.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Pachymatisma johnstonia O 2
Tethya aurantium O 1
Polymastia boletiformis F 2
Polymastia mamillaris O 1
Stelligera rigida O 1
Stelligera stuposa O 2
Cliona celata O 4
Esperiopsis fucorum F 2
Hemimycale columella O 2
Raspailia ramosa O 2
Dysidea fragilis F 3
Halecium halecinum F 1
Nemertesia antennina F 4
Nemertesia ramosa O 2
Alcyonium digitatum F 5
Urticina felina O 1
Actinothoe sphyrodeta O 2
Corynactis viridis F 2
Caryophyllia smithii F 4
Balanus crenatus O 2
Necora puber O 1
Calliostoma zizyphinum O 2
Crisiidae F 1
Alcyonidium diaphanum F 3
Flustra foliacea F 2
Bugula flabellata O 1
Bugula plumosa F 2
Pentapora foliacea O 1
Henricia oculata O 1
Asterias rubens F 3
Marthasterias glacialis O 1
Echinus esculentus O 2
Clavelina lepadiformis O 2

Example photographs of biotope


Erect branching sponge and Caryophyllia, Sligneach Mor, Sunart, Rohan Holt, © JNCC
Click on an image for a larger view


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