Description of biotope or habitat type

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   Fucoids in variable salinity

Physical habitat description

Salinity	Reduced (18-30ppt), Variable (18-35 ppt), Low (<18ppt)
Wave exposure	Sheltered, Very sheltered, Extremely sheltered
Tidal streams	Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum	Bedrock, boulders and cobbles
Zone	Eulittoral - lower, Eulittoral - mid, Eulittoral - upper, Eulittoral
Depth Band	Lower shore, Mid shore, Upper 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.

• 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.

Description

Blankets of fucoid seaweeds dominating sheltered to extremely sheltered rocky shores with variable salinity. The wrack Pelvetia canaliculata (PelVS) occurs on the upper shore, with the wrack Fucus spiralis (FspiVS) below. The middle shore is dominated by vast areas of the wrack Ascophyllum nodosum or the wrack Fucus vesiculosus (AscVS, FvesVS) or a mixture of both. The wrack Fucus serratus covers lower shore bedrock and boulders (FserVS). Fucus ceranoides can be found on extremly sheltered shores with variable or low salinity (Fcer). The variable salinity communities are species impoverished compared to fucoids in full salinity or in tide-swept conditions as red seaweeds and sponges are usually absent. Underneath the canopy are a few green seaweeds including Ulva intestinalis and Cladophora spp., while the red seaweed Vertebrata lanosa can be found as an epiphyte on A. nodosum. On the rock and among the boulders are the winkles Littorina littorea and Littorina saxatilis, the crab Carcinus maenas, the barnacles Semibalanus balanoides and Austrominius modestus and even the occasional mussel Mytilus edulis.