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Marine Habitat Classification

Description of biotope or habitat type

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   Fucus serratus on full salinity sheltered lower eulittoral rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Bedrock
Zone Eulittoral - lower
Depth Band 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 LR.LLR.F.Fserr.FS <I>Fucus serratus</I> on full salinity sheltered lower eulittoral 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'

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


Sheltered lower eulittoral rock subject to fully marine conditions characterised by a dense canopy of the wrack Fucus serratus. There is a wide range of associated species found on the surface of the rock underneath the canopy, including the barnacle Semibalanus balanoides, limpets Patella vulgata, winkles Littorina littorea, and even mussels Mytilus edulis can be present in cracks and crevices. These species are usually found in higher abundance further up on the shore. There may also be a number of other seaweeds present, including the red Corallina officinalis and Mastocarpus stellatus, the wrack Fucus vesiculosus and the green Ulva intestinalis, Ulva lactuca or Cladophora rupestris, though these usually are present in low numbers if present at all. The sponge Halichondria panicea can be present underneath the F. serratus canopy in moist cracks or minor overhangs. Polychaetes such as Spirobranchus triqueter and Spirorbis spp. are present in their white calcareous tubes on the rock.


This biotope usually occurs immediately below a Fucus vesiculosus-barnacle mosaic (FvesB) on moderately exposed shores or a dense canopy of F. vesiculosus (Fves) or Ascophyllum nodosum (Asc.FS) on sheltered shores; consequently low densities of these species (typically less than Frequent) may also occur in this biotope. The sub littoral fringe below on moderately exposed shores is dominated by the kelp Laminaria digitata (Ldig; Ldig.LdigBo), while the kelp Saccharina latissima may co-dominate on sheltered shores (Lsac.Ldig; Lsac.Ft).

Temporal variation

Fluctuations from year to year in the abundance of the F. serratus and the red seaweeds due to e.g. severe storms may convert this biotope into either Fser.R or into a red seaweed dominated biotope on moderately exposed shores.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Fucus serratus 44 Abundant 81-100%
Semibalanus balanoides 8 Frequent 41-60%
Patella vulgata 8 Occasional 41-60%
Cladophora rupestris 5 Frequent 41-60%
Ulva intestinalis 4 Frequent 21-40%
Littorina littorea 4 Occasional 41-60%
Mastocarpus stellatus 4 Frequent 41-60%
Spirobranchus triqueter 2 Occasional 21-40%
Spirorbinae 2 Common 21-40%
Spirorbis 2 Occasional 21-40%
Ulva lactuca 2 Occasional 21-40%
Corallina officinalis 1 Occasional 21-40%
Halichondria panicea 1 Frequent 21-40%
Mytilus edulis 1 Occasional 21-40%
Fucus vesiculosus 1 Occasional 21-40%

Similar biotopes or habitat types

Occurs on large boulders and in a wider exposure range. Has a high species richness and mobile species such as the crabs Porcellana platycheles and Cancer pagurus and the starfish Asterias rubens are present in low numbers.

Occurs in slightly more wave exposed conditions. The species diversity and abundance of red seaweeds are higher. D. pumila can form dense populations on the F. serratus fronds.

Occurs on bedrock and boulders in very sheltered conditions. It has a very high species diversity and sponges such as H. panicea and Hymeniacidon perlevis and bryozoans such as Electra pilosa or Alcyonidium gelatinosum are characteristic for this tide-swept biotope.

Occurs on variable salinity lower eulittoral rock. Similar species composition, but the individual M. edulis are large and the barnacle Austrominius modestus can be present in high numbers.

Classification history of this biotope or habitat type

Classification version Code


LR.LLR.F.Fserr.FS Fucus serratus on full salinity sheltered lower eulittoral rock, Long Taing of Newark, South Sanday. Sue Scott© JNCC
LR.LLR.F.Fserr.FS Fucus serratus on full salinity sheltered lower eulittoral rock, Long Taing of Newark, South Sanday. Sue Scott© JNCC

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