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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.

   Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed, Sheltered, Extremely sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Clean stone gravel with pebbles
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features

Biotope origin

Derived using data from Video/still
Faunal group Epifauna

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 SS.SCS.ICS.HchrEdw <I>Halcampa chrysanthellum</I> and <I>Edwardsia timida</I> on sublittoral clean stone gravel

  • 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.


Periodically disturbed sublittoral stone gravel with small pebbles characterised by the presence of the anemones Halcampa chrysanthellum and Edwardsia timida. Associated species are often typical of a hydroid/bryozoan turf with polychaetes such as Spirobranchus spp. encrusting larger pebbles and low numbers of syllid and phyllodocid polychaetes living interstitially. In some areas this biotope may also contain opportunistic red seaweeds and infauna such as Sabella pavonina. It should be noted that this habitat may show considerable variation in community composition and it is possible that it is a sub-biotope of other gravel biotopes.


This biotope tends to occur at the entrance to marine inlets where tidal currents are moderately strong.

Temporal variation

The faunal composition and species richness of this biotope may vary seasonally as a result of disturbance from increased wave or tidal action.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Edwardsia timida 18 Frequent 61-80%
Halcampa chrysanthellum 11 Rare 61-80%
Asterias rubens 6 Occasional 41-60%
Spirobranchus triqueter 6 Frequent 41-60%
Cylista elegans 6 Occasional 41-60%
Alcyonidium diaphanum 5 Occasional 41-60%
Lanice conchilega 4 Occasional 41-60%
Pagurus bernhardus 4 Rare 41-60%
Pholis gunnellus 3 Frequent 21-40%
Bryozoa 2 Occasional 21-40%
Carcinus maenas 2 Occasional 21-40%
Cerianthus lloydii 2 Occasional 21-40%
Edwardsia claparedii 2 21-40%
Obelia 2 Occasional 21-40%
Obelia geniculata 2 21-40%
Urticina felina 2 Occasional 21-40%
Alcyonium digitatum 1 Occasional 21-40%
Amphipholis squamata 1 21-40%
Chondrus crispus 1 21-40%
Chorda filum 1 21-40%
Clavelina lepadiformis 1 Rare 21-40%
Crossaster papposus 1 21-40%
Cryptopleura ramosa 1 21-40%
Desmarestia aculeata 1 21-40%
Dilsea carnosa 1 21-40%
Eudendrium 1 Rare 21-40%
Eupolymnia nebulosa 1 21-40%
Steromphala cineraria 1 21-40%
Saccharina latissima 1 21-40%
Nemertesia antennina 1 Rare 21-40%
Nitophyllum punctatum 1 21-40%
Pecten maximus 1 Rare 21-40%
Polysiphonia stricta 1 21-40%
Sabella pavonina 1 Rare 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code Habitat name
2015 (15.03) SS.SCS.ICS.HchrEdw Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel
2004 (04.05) SS.SCS.ICS.HchrEdw Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel
1997 (97.06) SS.IGS.FaG.HalEdw Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

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