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Marine Habitat Classification

Description of biotope or habitat type

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   Fucoids in tide-swept conditions

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Very strong (>6 kn), Strong (3-6 kn), Moderately strong (1-3 kn)
Substratum Bedrock, stable boulders, cobbles
Depth Band Lower shore, Mid 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 LR.HLR.FT Fucoids in tide-swept conditions

  • 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'

Point data based on records in the UK Marine Recorder Snapshot.


Biotope complex description Fucoid seaweeds in tide-swept conditions on sheltered to extremely sheltered mid eulittoral to lower eulittoral rocky shores, such as narrow channels in sea lochs. The middle shore can be dominated by the wrack Ascophyllum nodosum (AscT), while Fucus serratus is dominating the lower shore (FserT, FserTX). The high levels of water movement encourages a rich associated fauna including several filter-feeding groups. These include the sponges Grantia compressa, Halichondria panicea and Hymeniacidon perlevis which frequently occur on steep and overhanging faces of boulders and bedrock. It also includes the sea squirts Dendrodoa grossularia and Ascidiella scabra, which occur on steep surfaces and beneath boulders. Hydroids such as the pink Clava multicornis can form colonies on A. nodosum while Dynamena pumila is more often found on Fucus vesiculosus or F. serratus. Underneath the canopy formed by the brown seaweeds is a diverse community of the red seaweeds Gelidium pusillum, Chondrus crispus, Lomentaria articulata, Membranoptera alata and coralline crusts, but the green seaweeds Ulva intestinalis, Ulva lactuca and Cladophora rupestris can be present. The filamentous red seaweed Vertebrata lanosa can usually be found growing on A. nodosum. On the rock beneath are the limpet Patella vulgata and the barnacle Semibalanus balanoides, while the crab Carcinus maenas and a variety of winkles including Littorina littorea, Littorina fabalis and Littorina obtusata can be found on or among the boulders. The whelk Nucella lapillus can either be found in cracks and crevices.


Sheltered tide-swept shores (i.e. estuaries and sea lochs) below the Fucus spiralis and F. vesiculosus band and above the kelp dominated zone in the sublittoral.

Temporal variation

No temporal variation data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Fucus serratus 10 Common 81-100%
Ascophyllum nodosum 6 Abundant 41-60%
Corallinaceae 5 Frequent 61-80%
Dynamena pumila 5 Frequent 61-80%
Littorina 5 Occasional 61-80%
Patella vulgata 5 Occasional 61-80%
Ulva intestinalis 4 Occasional 61-80%
Halichondria panicea 4 Occasional 61-80%
Ulva lactuca 4 Occasional 61-80%
Nucella lapillus 4 Occasional 61-80%
Semibalanus balanoides 3 Frequent 41-60%
Carcinus maenas 3 Occasional 41-60%
Chondrus crispus 3 Frequent 41-60%
Mastocarpus stellatus 3 Frequent 41-60%
Cladophora rupestris 2 Frequent 21-40%
Dendrodoa grossularia 2 Frequent 41-60%
Steromphala cineraria 2 Frequent 41-60%
Hymeniacidon perlevis 2 Occasional 41-60%
Littorina littorea 2 Occasional 41-60%
Lomentaria articulata 2 Occasional 41-60%
Vertebrata lanosa 2 Frequent 21-40%
Spirobranchus triqueter 2 Occasional 41-60%
Spirorbinae 2 Frequent 21-40%
Fucus vesiculosus 2 Occasional 41-60%
Mytilus edulis 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

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