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Marine Habitat Classification

Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Hiatella-bored vertical sublittoral limestone rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock
Zone Circalittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features Vertical limestone or chalk.

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.SfR.Hia <I>Hiatella</I>-bored vertical sublittoral limestone 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.


Moderately exposed vertical and overhanging soft rock (typically chalk), subject to moderately strong to weak tidal streams, bored by the rock-boring mollusc Hiatella arctica. As with other biotopes in the soft rock complex, it is found in areas of high turbidity, where there is poor light penetration. There may be isolated clumps of the hydroid Nemertesia antennina and a sparse bryozoan turf formed by various crisiids, Crisularia plumosa and Bugula flabellate (often being grazed on by the nudibranch Antiopella cristata), Alcyonidium diaphanum, Flustra foliacea and Cellapora pumicosa. A patchy 'carpet' of the brittlestar Ophiothrix fragilis is often recorded along with other echinoderms such as Asterias rubens and Henricia sanguinolenta. Other species present include the colonial ascidians Polyclinum aurantium, Botrylloides leachii, Clavelina lepadiformis, Aplidium punctatum and Botryllus schlosseri, dead mans fingers Alcyonium digitatum and the crab Cancer pagurus. Sponges present include the boring sponge Cliona celata, Halichondria panicea, Myxilla incrustans, Leucosolenia botryoidesand Dysidea fragilis. Occasionally, the foliose red seaweed Delessaria sanguinea may be recorded.


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
Ophiothrix fragilis 10 Common 61-80%
Asterias rubens 9 Frequent 61-80%
Hiatella arctica 7 Common 61-80%
Crisiidae 5 Common 41-60%
Polyclinum aurantium 5 Frequent 61-80%
Botrylloides leachii 4 Frequent 41-60%
Crisularia plumosa 4 Frequent 41-60%
Alcyonidium diaphanum 3 Frequent 41-60%
Alcyonium digitatum 3 Common 41-60%
Aplidium punctum 2 Common 21-40%
Botryllus schlosseri 2 Occasional 21-40%
Bugulina flabellata 2 Frequent 41-60%
Cancer pagurus 2 Occasional 41-60%
Clavelina lepadiformis 2 Frequent 41-60%
Cliona celata 2 Frequent 21-40%
Delesseria sanguinea 2 Frequent 21-40%
Flustra foliacea 2 Common 21-40%
Halichondria panicea 2 Frequent 41-60%
Henricia sanguinolenta 2 Occasional 21-40%
Antiopella cristata 2 Frequent 21-40%
Leucosolenia botryoides 2 Frequent 41-60%
Cellepora pumicosa 1 Occasional 41-60%
Dysidea fragilis 1 21-40%
Myxilla incrustans 1 Occasional 21-40%
Nemertesia antennina 1 Frequent 21-40%
Sabellaria spinulosa 1 Frequent 21-40%

Similar biotopes or habitat types

Has seaweed community.

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