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IR.FIR.SG.CC.Mo
Coralline crusts and crustaceans on mobile boulders or cobbles in surge gullies

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Very exposed, Exposed, Moderately exposed 
 Tidal streams: Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) 
 Substratum: Boulders, cobbles, often with pebbles or gravel 
 Zone: Infralittoral 
 Depth Band: 0-5 m, 5-10 m, 10-20 m 
 Other Features: Mobile substrata 

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:
CC.Mob - Version: 97.06
EIR.Bcre - Version: 96.7

Distribution of habitat IR.FIR.SG.CC.Mo  Coralline crusts and crustaceans on mobile boulders or cobbles in surge gullies
Distribution of habitat IR.FIR.SG.CC.Mo Coralline crusts and crustaceans on mobile boulders or cobbles in surge gullies, 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

Highly mobile and scoured boulders and cobbles found on cave and gully floors and which often appear bare. Where there is sufficient light and stability, however, the boulders are encrusted by coralline algal crusts. Barnacles Balanus crenatus and keelworms Pomatoceros triqueter may survive in areas protected from severe abrasion. Crabs such as Cancer pagurus and Carcinus maenas may occur, often beneath and between the rocks, along with the gastropod Calliostoma zizyphinum. The anemone Actinia equina may be present in low numbers.

Situation

The slightly less-scoured walls often found above this biotope in caves and gullies are generally characterised by a similar, but richer community of scour-tolerant Balanus crenatus, Pomatoceros triqueter, coralline crusts and spirorbid worms (CC.BalPom). This impoverished biotope may form an intermediate between barren gravel and slightly more stable larger pebbles and cobbles which are covered by algae that are often found in the mouths of caves (FoSwCC).

Temporal variation

Winter storms periodically mobilise the boulders and cobbles, causing abrasion to any seasonal biota that may have developed over the calmer summer months.

Similar biotopes

IR.HIR.KSed.DesFilROccurs in similar conditions as CC.Mob but has a higher species diversity and has a high abundance of the brown seaweed Desmarestia aculeata.
IR.FIR.SG.CC.BalPomSeverely scoured vertical infralittoral rock with B. crenatus and/or P. triqueter with spirorbid worms and coralline crusts. Often occurs on nearby vertical rock.
IR.FIR.SG.FoSwCCThis biotope occurs in surge gully entrances on bedrock. The less scoured, more stable substrata allow foliose seaweeds develop.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Urticina felina O 12
Cancer pagurus O 11
Carcinus maenas R 23
Calliostoma zizyphinum O 13
Corallinaceae C 23
Rhodophycota indet.(non-calc.crusts) F 18

Example photographs of biotope

No characteristic photos currently available. If you are able to provide a photograph of this biotope please contact .


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