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Marine Habitat Classification

Description of biotope or habitat type

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   Crustose sponges on extremely wave-surged infralittoral cave or gully walls

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Very exposed, Exposed
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; massive boulders
Zone Infralittoral - upper, Sublittoral fringe
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features Extreme wave surge and scour on

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.CrSp Crustose sponges on extremely wave-surged infralittoral cave or gully walls

  • 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.


Walls, or massive boulders, in caves or gullies that are subject to severe wave-surge and characterised by extensive thin crusts of the sponge Halichondria panicea with smaller patches of other sponges such as Amphilectus fucorum or Clathrina coriacea. Small turfs of robust hydroids, such as Diphasia rosacea and Ventromma halecioides, and patches of the barnacle Balanus crenatus, coralline crusts and tube-building spirorbid polychaetes may be present. The starfish Henricia spp., the brittlestar Ophiopholis aculeata and the crabs Cancer pagurus and Necora puber can be present. The anemones Cylista elegans, Urticina felina and Actinia equina can be found in cracks and crevices or under boulders. The mussel Mytilus edulis may be present in low densities.


This surge-tolerant biotope of low-growing fauna is typically confined to the mid or rear section of caves (or the narrowest part of gullies) where the wave-surge is intensified. It generally abuts the less surged ascidian-sponge communities (CrSpAsAn, DenCcor and CrSpAsDenB). A highly scoured zone of barnacles and calcareous tubeworms often form a zone below, abutting the cave/gully floor (CC.BalPom).

Temporal variation


Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Halichondria panicea 20 Abundant 41-60%
Corallinaceae 13 Frequent 41-60%
Spirorbinae 8 Common 21-40%
Henricia 7 Occasional 21-40%
Clathrina coriacea 6 Frequent 41-60%
Pachymatisma johnstonia 5 Occasional 41-60%
Balanus crenatus 4 Frequent 21-40%
Leuconia nivea 4 Common 21-40%
Porifera indet crusts 4 Occasional 21-40%
Cancer pagurus 3 Occasional 21-40%
Dendrodoa grossularia 3 Occasional 21-40%
Necora puber 3 Occasional 21-40%
Ophiopholis aculeata 3 Frequent 21-40%
Urticina felina 3 Occasional 21-40%
Actinia equina 2 Occasional 21-40%
Cylista elegans 2 Frequent 21-40%

Similar biotopes or habitat types



Classification history of this biotope or habitat type

Classification version Code
1997 (97.06) EIR.SC

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