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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

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.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 Turritellinella tricarinata may also be present in some areas.


This biotope typically occurs in waters shallower than about 5 m in sheltered basins of sea lochs 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%
Carcinus maenas 27 Frequent 81-100%
Asterias rubens 6 Rare 61-80%
Diatoms - film 5 41-60%
Pagurus bernhardus 5 41-60%
Saccharina latissima 3 41-60%
Liocarcinus depurator 3 41-60%
Gobiidae 2 21-40%
Pecten maximus 2 21-40%
Turritellinella tricarinata 2 21-40%
Chlamys 1 21-40%
Seraphsidae 1 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.IFiMu.Are Arenicola marina in infralittoral mud
2004 (04.05) SS.SMu.IFiMu.Are Arenicola marina in infralittoral mud
1997 (97.06) SS.IMU.MarMu.AreSyn Arenicola marina and synaptid holothurians in extremely shallow soft mud
1996 (6.95) LMU.Are (part)

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