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Marine Habitat Classification

Description of biotope or habitat type

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   Arenicola marina in infralittoral mud

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Mud
Zone Infralittoral
Depth Band 0-5 m, 5-10 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.IFiMu.Are <I>Arenicola marina</I> in infralittoral 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 very shallow, extremely sheltered, very soft muds Arenicola marina may form very conspicuous mounds and casts. This biotope may also contain synaptid holothurians such as Labidoplax media and Leptosynapta bergensis or L. inhaerens. However these species may be under recorded (possibly due to periodicity in feeding) and are not considered characteristic of this biotope. Other conspicuous fauna may include Carcinus maenas, Asterias rubens and Pagurus bernhardus whilst the scallop Pecten maximus and the turret shell Turritella communis may also be present in some areas.


This biotope typically occurs in waters shallower than about 5 m in sheltered basins of sealochs and lagoons that may be partially separated from the open sea by tidal narrows or rapids.

Temporal variation

Sediment surfaces may become covered by a diatom film at certain times of the year

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Arenicola marina 34 Common 81-100 %
Terebellidae 1 21-40 %
Pagurus bernhardus 5 41-60 %
Liocarcinus depurator 3 41-60 %
Carcinus maenas 27 Frequent 81-100 %
Turritella communis 2 21-40 %
Pecten maximus 2 21-40 %
Chlamys 1 21-40 %
Asterias rubens 6 Rare 61-80 %
Gobiidae 2 21-40 %
Diatoms - film 5 41-60 %
Laminaria saccharina 3 41-60 %

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
96.7 LMU.Are in part

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