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Marine Habitat Classification

Description of biotope or habitat type

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   Silted cape-form Laminaria hyperborea on very sheltered infralittoral rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock & boulders
Zone Infralittoral - upper
Depth Band 0-5 m, 5-10 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 IR.LIR.K.LhypCape Silted cape-form <I>Laminaria hyperborea</I> on very sheltered infralittoral 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.


Cape-form of the kelp Laminaria hyperborea on very silted rock, particularly in extremely sheltered sealochs of western Scotland. Below the huge kelp fronds (which often trail onto the seabed) foliose seaweeds form a silted understorey on the rock including Phycodrys rubens, Delesseria sanguinea, Cryptopleura ramosa and Plocamium cartilagineum as well as coralline crusts. At some sites the filamentous red seaweed Bonnemaisonia hamifera, Heterosiphonia plumosa and Vertebrata byssoides may carpet the seabed. Ascidians, particularly Ascidiella aspersa, Ascidia mentula, Ciona intestinalis and Clavelina lepadiformis thrive well in these conditions. The echinoderms Antedon bifida, Echinus esculentus and Asterias rubens are often present along with the gastropod Steromphala cineraria. An abundant growth of the hydroid Obelia geniculata can cover the silted kelp fronds along with the bryozoan Membranipora membranacea. The anthozoan Caryophyllia smithii can be present among the kelp holdfasts. The tube-building polychaete Spirobranchus triqueter can be present on the rock surface along with the crab Necora puber. This biotope generally occurs on shallow bedrock or boulder slopes or isolated rocks protruding through muddy sediment.


This biotope is often present on rocky outcrops surrounded by muddy sediments (such as VirOphPmax). Deeper, nearby rock, beyond the limit of foliose seaweeds, is often dominated by solitary ascidians (AmenCio).

Temporal variation


Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Laminaria hyperborea 18 Abundant 81-100%
Ascidia mentula 6 Frequent 81-100%
Phycodrys rubens 5 Occasional 61-80%
Asterias rubens 4 Occasional 61-80%
Clavelina lepadiformis 4 Frequent 61-80%
Steromphala cineraria 4 Occasional 61-80%
Echinus esculentus 4 Occasional 61-80%
Corallinaceae 3 Common 41-60%
Antedon bifida 3 Occasional 41-60%
Ascidiella aspersa 3 Occasional 41-60%
Delesseria sanguinea 3 Occasional 61-80%
Spirobranchus triqueter 3 Frequent 61-80%
Bonnemaisonia asparagoides 2 Occasional 41-60%
Caryophyllia smithii 2 Occasional 41-60%
Dictyota dichotoma 2 Occasional 41-60%
Obelia geniculata 2 Frequent 41-60%
Membranipora membranacea 1 Occasional 21-40%
Vertebrata byssoides 1 Frequent 21-40%
Ciona intestinalis 1 Occasional 41-60%
Cryptopleura ramosa 1 Occasional 21-40%
Desmarestia aculeata 1 Occasional 21-40%
Heterosiphonia plumosa 1 Occasional 21-40%
Necora puber 1 Rare 41-60%
Plocamium cartilagineum 1 Frequent 41-60%

Similar biotopes or habitat types

Occurs on moderately exposed rock and supports a dense understorey of foliose red seaweeds beneath the kelp canopy. L. hyperborea is not found in cape-form. A more diverse range of fauna such as sponges and anthozoans are also present in IR.MIR.KR.Lhyp.Ft.

S. latissima and L. hyperborea generally occur together in predominantly "sheltered" sites. Large solitary ascidians (Ascidiella spp.) are more prevalent in IIR.LIR.K.LhypCape.

Occurs in similar sheltered conditions but there are fewer species present in IR.LIR.K.Slat.Ft, particularly fewer red seaweeds and no L. hyperborea.

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