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Marine Habitat Classification

Description of biotope or habitat type

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   Amphiura filiformis and Nuculoma tenuis in circalittoral and offshore sandy mud

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Very weak (negligible)
Substratum Sandy mud
Zone Circalittoral
Depth Band 50-100 m
Other Features

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.AfilNten <I>Amphiura filiformis</I> and <I>Nuculoma tenuis</I> in circalittoral and offshore 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.


In cohesive and non-cohesive sandy mud, off moderately exposed coasts in deep water dense populations of Amphiura filiformis with the bivalve Nuculoma tenuis may occur. This biotope together with AfilMysAnit, ThyNten and OfusAfil may be part of the Amphiura filiformis dominated infralittoral etage described by Glemarec (1973) and part of the 'off-shore muddy sand association' described by other workers (Jones 1951; Mackie 1990). Other species characteristic of this biotope may include the echinoderms Ophiura albida and Echinocardium flavescens and the bivalve Mysella bidentata. Phaxas pellucidus, Owenia fusiformis and Virgularia mirabilis may also be present. At the sediment surface the hydroid Sertularia argentea may be present although only at very low abundances. Variations of this biotope exist in the northern North Sea (see below) and it is possible that more than one entity exists for this biotope.


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
Hydrallmania falcata 8 Rare 41-60 %
Sertularia argentea 26 Rare 61-80 %
Obelia longissima 57 Rare 81-100 %
Virgularia mirabilis 3 Abundant 41-60 %
Diplocirrus glaucus 2 61-80 %
Ophelina acuminata 2 Common 41-60 %
Scalibregma inflatum 2 41-60 %
Owenia fusiformis 3 Common 41-60 %
Lagis koreni 2 Common 41-60 %
Cylichna cylindracea 2 Common 41-60 %
Antalis entalis 2 Frequent 41-60 %
Nuculoma tenuis 15 Common 81-100 %
Mysella bidentata 9 Common 61-80 %
Phaxas pellucidus 3 Frequent 61-80 %
Abra nitida 2 41-60 %
Cellaria fistulosa 8 Rare 41-60 %
Amphiura filiformis 22 Super abundant 81-100 %
Ophiura albida 12 Super abundant 81-100 %
Echinocardium flavescens 10 Abundant 61-80 %

Similar biotopes or habitat types

AfilNten may be distinguished from AfilMysAnit by the abundance of the characterising species Nuculoma tenuis in AfilNten and by the importance of other characterising species such as Thysanocardia procera and Nephtys incise in AfilMysAnit. AfilNten is also generally found at greater depths and may be a deeper water extension of AfilMysAnit.

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