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Marine Habitat Classification

Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Kelp with cushion fauna and/or foliose red seaweeds

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Extremely exposed, Very exposed, Exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; stable boulders
Zone Infralittoral, Sublittoral fringe
Depth Band 0-5 m, 5-10 m, 10-20 m, 20-30 m, 30-50 m, Lower shore
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.HIR.KFaR Kelp with cushion fauna and/or foliose red seaweeds

  • 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.


Rocky habitats in the infralittoral zone subject to exposed to extremely exposed wave action or strong tidal streams. Typically the rock supports a community of kelp Laminaria hyperborea with foliose seaweeds and animals, the latter tending to become more prominent in areas of strongest water movement (LhypFa, LhypR and LhypR.Pk). The depth to which the kelp extends varies according to water clarity, exceptionally (e.g. St Kilda) reaching 45 m. In some areas, there may be a band of dense foliose seaweeds (reds or browns) below the main kelp zone (FoR). The sublitttoral fringe is characterised by dabberlocks Alaria esculenta (Ala biotopes). In very strong wave action the sublittoral fringe A. esculenta zone extends to 5 to 10 m depth, whilst at Rockall A. esculenta replaces L. hyperborea as the dominant kelp in the infralittoral zone (AlaAnCrSp).


Very exposed rocky coasts, from low water to depths up to 45m.

Temporal variation

Winter storms may remove patches of kelp, and fast-growing annuals may form a temporary forest (LsacSac).

Characterising species

Taxon Typical abundance - SACFOR scale % of core records where taxon was recorded
Alaria esculenta Common 41-60%
Alcyonium digitatum Occasional 21-40%
Asterias rubens Occasional 41-60%
Botryllus schlosseri Occasional 21-40%
Calliostoma zizyphinum Occasional 21-40%
Corallina officinalis Frequent 21-40%
Corallinaceae Common 61-80%
Corynactis viridis Frequent 21-40%
Cryptopleura ramosa Frequent 41-60%
Cylista elegans Occasional 21-40%
Delesseria sanguinea Frequent 41-60%
Dictyota dichotoma Frequent 41-60%
Echinus esculentus Occasional 21-40%
Laminaria hyperborea Common 41-60%
Metacallophyllis laciniata Occasional 21-40%
Plocamium cartilagineum Frequent 41-60%
Spirobranchus triqueter Occasional 21-40%
Urticina felina Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

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