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Marine Habitat Classification

Description of biotope or habitat type

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   Circalittoral faunal communities in variable salinity

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Bedrock, cobbles
Zone Circalittoral - lower, Circalittoral - upper
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 CR.MCR.CFaVS Circalittoral faunal communities in variable salinity

  • 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.


This biotope complex occurs on wave-sheltered, variable salinity bedrock and cobbles, subject to moderately strong to weak tidal streams. This complex contains a suite of sponges able to tolerate the variable salinity conditions like Hymeniacidon perlevis, Suberites ficus, Halichondria panicea, Halichondria bowerbanki, Cliona celata and Leucosolenia botryoides. The barnacle Balanus crenatus is frequently recorded in this complex. A sparse hydroid/bryozoan turf composed primarily of Nemertesia antennina, Nemerteis ramosa, Plumularia setacea, Alcyonidium diaphanum and Crisularia plumosa is often recorded. Other species recorded are the ascidians Clavelina lepadiformis, Morchellium argus and Dendrodoa grossularia, the anemones Metridium senile and Sagartia troglodytes, the starfish Asterias rubens and the crab Carcinus maenas. Two biotopes have been identified within this complex: CuSpH (cushion sponges with hydroids) and HbowEud.


No situation data available.

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
Balanus crenatus 9 Common 41-60%
Clavelina lepadiformis 8 Frequent 41-60%
Hymeniacidon perlevis 8 Frequent 41-60%
Suberites ficus 8 Frequent 61-80%
Halichondria panicea 6 Frequent 41-60%
Halichondria bowerbanki 5 Frequent 41-60%
Nemertesia antennina 5 Frequent 41-60%
Asterias rubens 4 Occasional 41-60%
Carcinus maenas 4 Occasional 41-60%
Plumularia setacea 4 Occasional 41-60%
Metridium senile 3 Occasional 21-40%
Crisularia plumosa 2 Occasional 21-40%
Morchellium argus 2 Occasional 21-40%
Nemertesia ramosa 2 Frequent 21-40%
Alcyonidium diaphanum 1 Occasional 21-40%
Cliona celata 1 Occasional 21-40%
Dendrodoa grossularia 1 Occasional 21-40%
Leucosolenia botryoides 1 Frequent 21-40%
Sagartia troglodytes 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

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