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Marine Habitat Classification

Description of biotope or habitat type

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   Brachiopod and ascidian communities

Physical habitat description

Salinity Full (30-35 ppt), Reduced (18-30ppt)
Wave exposure Sheltered, Very sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock, boulders
Zone Circalittoral - lower, Circalittoral - upper
Depth Band 5-10 m, 10-20 m, 20-30 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.LCR.BrAs Brachiopod and ascidian communities

  • 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 the wave-sheltered, circalittoral bedrock and boulders subject to weak tidal streams. The biotopes within this complex are typically found in the Scottish sealochs (with the exception of LgAsSp, recorded off Ireland) and are characterised by brachipod and ascidian communities. Ascidians often recorded in this complex are Ciona intestinalis, Ascidia mentula, Ascidia virginea and Clavelina lepadiformis. The brachiopod Novocrania anomala is also characteristic of the biotopes within this complex recorded in Scottish sealochs. The polychaete Spirobranchus triqueter, the saddle oyster Pododesmus patelliformis, the cup coral Caryophyllia smithii and encrusting red algae are frequently recorded on the rocky substrata. Echinoderms such as the brittlestars Ophiothrix fraglis, Ophiocomina nigra and Ophiura albida, the starfish Asterias rubens, Crossaster papposus and Henricia oculata, the crinoid Antedon bifida and the urchin Echinus esculentus are all found in this complex. Other species present include the squat lobster Munida rugosa, the hermit crab Pagurus bernhardus, Alcyonium digitatum, the anemone Protanthea simplex and the hydroid Kirchenpaueria pinnata. Within this biotope complex, four biotopes have been identified: AmenCio, LgAsSp, AntAsH and NeoPro.


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
Corallinaceae 8 Common 41-60%
Ophiothrix fragilis 8 Frequent 61-80%
Spirobranchus triqueter 8 Frequent 61-80%
Echinus esculentus 7 Occasional 61-80%
Ascidia mentula 5 Occasional 61-80%
Asterias rubens 5 Occasional 61-80%
Ciona intestinalis 5 Occasional 61-80%
Ophiocomina nigra 4 Frequent 41-60%
Munida rugosa 3 Occasional 41-60%
Novocrania anomala 3 Frequent 21-40%
Pagurus bernhardus 3 Occasional 41-60%
Alcyonium digitatum 2 Occasional 21-40%
Caryophyllia smithii 2 Occasional 41-60%
Corella parallelogramma 2 Occasional 41-60%
Crossaster papposus 2 Occasional 41-60%
Ophiura albida 2 Occasional 21-40%
Pododesmus patelliformis 2 Occasional 21-40%
Protanthea simplex 2 Occasional 21-40%
Antedon bifida 1 Occasional 21-40%
Ascidia virginea 1 Occasional 21-40%
Clavelina lepadiformis 1 Occasional 21-40%
Henricia oculata 1 Rare 21-40%
Kirchenpaueria pinnata 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

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