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Marine Habitat Classification

Description of biotope or habitat type

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   Mixed Laminaria hyperborea and Saccharina latissima on sheltered infralittoral rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; boulders
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 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.LhypSlat Mixed <I>Laminaria hyperborea</I> and <I>Saccharina latissima</I> on 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.


Mixed Laminaria hyperborea and Saccharina latissima on bedrock and boulders in sheltered infralittoral habitats. Typically subject to weak tidal streams and rather silty conditions. Beneath the kelp is an associated under-storey flora of foliose red seaweeds including Plocamium cartilagineum, Cryptopleura ramosa and Metacallophyllis laciniata as well as the brown seaweeds Dictyota dichotoma, Cutleria multifida and Desmarestia aculeata. The stipes of L. hyperborea may be densely covered with red seaweeds such as Phycodrys rubens and Delesseria sanguinea as well as the solitary ascidian Clavelina lepadiformis and the featherstar Antedon bifida. The fronds are often epiphytised by the hydroid Obelia geniculata and the bryozoan Membranipora membranacea. Beneath the kelp canopy, the faunal component is generally less diverse than the more exposed kelp forests, dominated by the echinoderms Echinus esculentus and Asterias rubens, but the tops shells Steromphala cineraria and Calliostoma zizyphinum can be common as well. The crab Necora puber and the brittlestar Ophiothrix fragilis can be found in cracks and crevices, while the tube-building polychaete Spirobranchus triqueter and coralline crusts are present on the rock surface. Although there is a reduced number of species by comparison to the more exposed L. hyperborea forests (Lhyp.Ft), there are considerably more algae species than occur in the more sheltered L. saccharina forests (Lsac.Ft). This biotope is predominately found in the shelter of fjordic sealochs in Scotland. Where it does occur in south-west Britain the mixed kelp forest may also include the southern kelp Laminaria ochroleuca. Three variants has been described: The kelp forest in the upper infralittoral (LhypLsac.Ft), grading to a kelp park with increasing depth (LhypLsac.Pk) as well as a grazed variant (LhypLsac.Gz).


No situation data available.

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 15 Common 81-100%
Saccharina latissima 10 Frequent 81-100%
Corallinaceae 6 Common 61-80%
Spirobranchus triqueter 6 Frequent 61-80%
Steromphala cineraria 5 Frequent 61-80%
Echinus esculentus 5 Occasional 61-80%
Asterias rubens 4 Occasional 61-80%
Delesseria sanguinea 3 Occasional 41-60%
Phycodrys rubens 3 Frequent 41-60%
Plocamium cartilagineum 3 Occasional 41-60%
Calliostoma zizyphinum 2 Occasional 41-60%
Clavelina lepadiformis 2 Occasional 41-60%
Obelia geniculata 2 Occasional 41-60%
Membranipora membranacea 1 Occasional 21-40%
Metacallophyllis laciniata 1 Occasional 41-60%
Cryptopleura ramosa 1 Occasional 41-60%
Cutleria multifida 1 Frequent 21-40%
Desmarestia aculeata 1 Occasional 21-40%
Dictyota dichotoma 1 Occasional 41-60%
Necora puber 1 Occasional 41-60%
Ophiothrix fragilis 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
2015 (15.03) IR.LIR.K.LhypLsac

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