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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.

   Circalittoral sandy mud

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered, Very sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Mud with a significant fine to very fine sand fraction
Zone Circalittoral
Depth Band 5-10 m, 10-20 m, 20-30 m, 30-50 m, 50-100 m
Other Features

Biotope origin

Derived using data from Various
Faunal group Infauna

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.SMu.CSaMu Circalittoral sandy mud

  • 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.


Circalittoral, cohesive sandy mud, typically with over 20% silt/clay, generally in water depths of over 10 m, with weak or very weak tidal streams. This habitat is generally found in deeper areas of bays and marine inlets or offshore from less wave exposed coasts. Seapens such as Virgularia mirabilis and brittlestars such as Amphiura spp. are particularly characteristic of this habitat whilst infaunal species include the tube building polychaetes Lagis koreni and Owenia fusiformis, and deposit feeding bivalves such as Kurtiella bidentata and Abra spp.


No situation data available.

Temporal variation

No temporal data available.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Kurtiella bidentata 19 Common 61-80%
Amphiura filiformis 18 Super abundant 61-80%
Virgularia mirabilis 12 Occasional 61-80%
Cerianthus lloydii 9 Occasional 41-60%
Asterias rubens 8 Occasional 61-80%
Pagurus bernhardus 8 Occasional 41-60%
Pecten maximus 7 Occasional 41-60%
Abra nitida 6 Abundant 41-60%
Ophiura albida 6 Frequent 41-60%
Phoronis 5 Common 41-60%
Liocarcinus depurator 4 Occasional 41-60%
Nemertea 4 Common 41-60%
Ophiura ophiura 4 Frequent 41-60%
Lagis koreni 3 Common 41-60%
Lanice conchilega 3 Occasional 21-40%
Nephtys incisa 3 41-60%
Ophiuroidea 2 Abundant 21-40%
Amphiura filiformis 2 Frequent 21-40%
Cirratulidae 2 Abundant 21-40%
Diplocirrus glaucus 2 41-60%
Melinna palmata 2 21-40%
Owenia fusiformis 2 Common 41-60%
Pagurus prideaux 2 Rare 21-40%
Pariambus typicus 2 Frequent 21-40%
Pholoe inornata 2 Frequent 21-40%
Thysanocardia procera 2 Common 21-40%
Turritellinella tricarinata 2 Occasional 21-40%
Echinus esculentus 2 Occasional 21-40%
Abra alba 1 Common 21-40%
Aporrhais pespelecani 1 Rare 21-40%
Chaetopterus variopedatus 1 Occasional 21-40%
Kirchenpaueria pinnata 1 Occasional 21-40%
Hilbigneris gracilis 1 Common 21-40%
Nemertesia ramosa 1 Occasional 21-40%
Ennucula tenuis 1 Frequent 21-40%
Phaxas pellucidus 1 Common 21-40%
Spirobranchus triqueter 1 Occasional 21-40%
Scalibregma inflatum 1 Common 21-40%
Seraphsidae 1 Occasional 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.SMu.CSaMu Circalittoral sandy mud
2004 (04.05) SS.SMu.CSaMu Circalittoral sandy mud
1997 (97.06) Part of SS.CMS Circalittoral muddy sands

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