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Marine Habitat Classification

Description of biotope or habitat type

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   Laminaria hyperborea and red seaweeds on exposed vertical rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed, Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features Vertical 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.

Distribution of habitat IR.HIR.KFaR.LhypRVt <I>Laminaria hyperborea</I> and red seaweeds on exposed vertical rock

  • 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.


On exposed coasts with moderately strong to weak tidal currents generally at depths of 0-10m, vertical rock communities dominated by frequent Laminaria hyperborea and its commonly associated red seaweeds Delesseria sanguinea, Cryptopleura ramosa and Plocamium cartilagineum can be found. Within this biotope the jewel anemone Corynactis viridis is frequently found in dense aggregations attached to the vertical rock surface. This biotope contains 5 sub-biotopes, distinguished by their biogeography. On the west coast of Scotland, the Northern Isles and the Isle of Man on extremely exposed coasts a variant of this biotope characterised by frequent Metridium senile and occasional Cylista elegans can be found. Further south on the west coast of Ireland, southern Scotland, Wales, and south west England a second variant characterised by frequent Alcyonium digitatum and occasional Cliona celata can be distinguished. A third variant has been recorded from Northern Ireland characterised by the red seaweeds Lithophyllum and Ptilota gunneri, the sea squirt Dendrodoa grossularia and the bryozoan Membranipora membranacea. South from the Isle of Man, on the Welsh Coast, and on the south west and southern English coasts a fourth variant of this biotope is found, which is characterised by the barnacle Balanus crenatus, which may be more frequent in this sub-biotope, and the rarity of Alcyonium digitatum, a species which is more frequent in other variants. This variant has mainly been recorded in shallow water (0-5m). The final biogeographic variant of this biotope is, as with the previous variant, found on the coasts of Wales and south west England. It can be distinguished from the previous variant by the frequent Diplosoma listerianum and occasional Lissoclinum perforatum, although these species are not always present.


Open rocky coasts of the south-west, west and north-west.

Temporal variation

No temporal data available

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Corynactis viridis 5 Frequent 61-80%
Delesseria sanguinea 5 Frequent 61-80%
Laminaria hyperborea 5 Frequent 61-80%
Plocamium cartilagineum 5 Occasional 61-80%
Cryptopleura ramosa 4 Frequent 61-80%
Alcyonium digitatum 3 Occasional 41-60%
Caryophyllia smithii 3 Occasional 41-60%
Dictyota dichotoma 3 Frequent 41-60%
Corallinaceae 2 Frequent 41-60%
Asterias rubens 2 Occasional 41-60%
Botryllus schlosseri 2 Occasional 41-60%
Metacallophyllis laciniata 2 Occasional 41-60%
Cancer pagurus 2 Rare 41-60%
Clavelina lepadiformis 2 Occasional 41-60%
Dysidea fragilis 2 Occasional 41-60%
Hypoglossum hypoglossoides 2 Occasional 41-60%
Cylista elegans 2 Occasional 41-60%
Calliostoma zizyphinum 1 Occasional 41-60%
Corallina officinalis 1 Occasional 21-40%
Crisiidae 1 Frequent 21-40%
Erythroglossum laciniatum 1 Frequent 21-40%
Amphilectus fucorum 1 Occasional 21-40%
Halichondria panicea 1 Occasional 21-40%
Kallymenia reniformis 1 Occasional 41-60%
Marthasterias glacialis 1 Occasional 41-60%
Pachymatisma johnstonia 1 Occasional 41-60%
Phyllophora crispa 1 Occasional 21-40%
Echinus esculentus 1 Occasional 21-40%

Similar biotopes or habitat types

Much more species poor, with red algae sparse or absent.

Classification history of this biotope or habitat type

Classification version Code
1995 LRK.CAT

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