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Marine Habitat Classification

Description of biotope or habitat type

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   Suberites spp. with a mixed turf of crisiids and Bugula spp. on heavily silted moderately wave-exposed shallow circalittoral rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn)
Substratum Bedrock, boulders
Zone Circalittoral - lower, Circalittoral - upper
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features Extremely shallow

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.HCR.XFa.SubCriTf <I>Suberites</I> spp. with a mixed turf of crisiids and <I>Bugula</I> spp. on heavily silted moderately wave-exposed shallow circalittoral 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'
  • 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 is found on heavily silted, moderately wave-exposed circalittoral bedrock and boulders (often limestone) that are subject to moderately strong tidal streams. A very high silt loading in the water column means that this 'circalittoral' biotope occurs at unusually shallow depths (1 - 10 m BCD). It is characterised by a mixed faunal turf and `massive' examples of the sponges Suberites ficus, Suberites carnosus and Hymeniacidon perlevis. Other sponges recorded in this biotope are Cliona celata, Halichondria panicea, Amphilectus fucorum, Raspailia ramosa, Polymastia mamillaris, Dysidea fragilis, Sycon ciliatum, Stelligera montagui and Haliclona oculata. Also characteristic of this biotope is a dense bryozoan turf with one or more crisiid species, Flustra foliacea and Crisularia plumosa. The polychaete Polydora spp. and the rock-boring bivalve Hiatella arctica are able to bore into the relatively soft limestone. There is an ascidian component to the biotope, with Morchellium argus and Clavelina lepadiformis among the most abundant. There may be scattered clumps of the hydroids Abietinaria abietina and Hydrallmania falcata. Other species present include the anemones Metridium senile, Cylista elegans and Urticina felina, the starfish Asterias rubens, the crab Necora puber, the nudibranch Antiopella cristata and the soft coral Alcyonium digitatum. This biotope has currently only been recorded off the east coast of Anglesey, Wales.


No situation data available.

Temporal variation

Not known

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Metridium senile 6 Common 81-100%
Asterias rubens 5 Frequent 81-100%
Cliona celata 5 Frequent 81-100%
Hiatella arctica 5 Frequent 81-100%
Polydora 5 Frequent 81-100%
Suberites ficus 5 Frequent 81-100%
Alcyonium digitatum 4 Frequent 81-100%
Crisiidae 4 Frequent 81-100%
Amphilectus fucorum 4 Frequent 81-100%
Halichondria panicea 4 Frequent 81-100%
Morchellium argus 4 Occasional 81-100%
Cylista elegans 4 Frequent 81-100%
Urticina felina 4 Occasional 81-100%
Hymeniacidon perlevis 3 Frequent 61-80%
Suberites carnosus 3 Occasional 81-100%
Abietinaria abietina 2 Frequent 61-80%
Crisularia plumosa 2 Frequent 61-80%
Clavelina lepadiformis 2 Occasional 61-80%
Dysidea fragilis 2 Frequent 61-80%
Flustra foliacea 2 Frequent 61-80%
Hydrallmania falcata 2 Occasional 61-80%
Antiopella cristata 2 Occasional 61-80%
Necora puber 2 Occasional 61-80%
Polymastia mamillaris 2 Frequent 61-80%
Raspailia ramosa 2 Occasional 61-80%
Sycon ciliatum 2 Occasional 61-80%
Stelligera montagui 2 Frequent 61-80%
Haliclona oculata 1 Occasional 61-80%

Similar biotopes or habitat types

This biotope is similar to CR.HCR.XFa.SubCriTf but is found in slighty more wave-sheltered sites, and at deeper depths. It also does not have 'massive' examples of Suberites spp. present in CR.HCR.XFa.SubCriTf.

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