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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.

   Infralittoral sandy mud

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Mud with a fine to very fine sand fraction
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 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.ISaMu Infralittoral 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.


Infralittoral, cohesive sandy mud, typically with over 20% silt/clay, in depths of less than 15-20 m. This habitat is generally found in sheltered bays or marine inlets and along sheltered areas of open coast. Typical species include a rich variety of polychaetes including Melinna palmate, tube building amphipods (Ampelisca spp.) and deposit feeding bivalves such as Macoma balthica and Kurtiella bidentata. Seapens such as Virgularia mirabilis and brittlestars such as Amphiura spp. may be present but not in the same abundances as found in deeper circalittoral waters.


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
Cylista undata 21 Occasional 61-80%
Nephtys hombergii 20 Common 61-80%
Carcinus maenas 16 Occasional 41-60%
Abra alba 8 Common 41-60%
Nucula nitidosa 8 Frequent 41-60%
Macoma balthica 7 Frequent 21-40%
Pagurus bernhardus 7 Occasional 41-60%
Ascidiella aspersa 6 Frequent 41-60%
Capitella capitata 5 Abundant 21-40%
Melinna palmata 5 Abundant 21-40%
Nematoda 4 Frequent 41-60%
Hydractinia echinata 4 Occasional 21-40%
Seraphsidae 4 Occasional 21-40%
Asterias rubens 3 Occasional 21-40%
Cerianthus lloydii 3 Occasional 21-40%
Liocarcinus depurator 3 Occasional 21-40%
Scoloplos armiger 3 Abundant 21-40%
Pomatoschistus 3 Occasional 21-40%
Arenicola marina 2 Occasional 1-20%
Magelona filiformis 2 Common 21-40%
Metridium senile 2 Rare 21-40%
Kurtiella bidentata 2 Frequent 21-40%
Myxicola infundibulum 2 Occasional 21-40%
Nemertea 2 Common 21-40%
Thyasira flexuosa 2 Frequent 41-60%
Chaetozone gibber 2 Abundant 21-40%
Ampelisca brevicornis 1 Frequent 21-40%
Ampelisca tenuicornis 1 Frequent 21-40%
Euclymene oerstedii 1 Abundant 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.ISaMu Infralittoral sandy mud
2004 (04.05) SS.SMu.ISaMu Infralittoral sandy mud
1997 (97.06) Part of SS.IMS.FaMS Shallow muddy sand faunal communities

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