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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.

   Burrowing megafauna and Maxmuelleria lankesteri in circalittoral mud

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Mud
Zone Circalittoral
Depth Band 10-20 m, 20-30 m, 30-50 m, 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.CFiMu.MegMax Burrowing megafauna and <I>Maxmuelleria lankesteri</I> in circalittoral 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 circalittoral stable mud distinctive populations of megafauna may be found. These typically include Nephrops norvegicus, Calocaris macandreae and Callianassa subterranea. Large mounds formed by the echiuran Maxmuelleria lankesteri are also frequent in this biotope. The seapen Virgularia mirabilis may occur occasionally in this biotope but not in the same abundance as SpnMeg to which MegMax is closely allied. Infaunal species may include Nephtys hystricis, Chaetozone setosa, Amphiura chiajei and Abra alba.


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
Virgularia mirabilis 6 Occasional 41-60 %
Cerianthus lloydii 4 Rare 41-60 %
Maxmuelleria lankesteri 13 Frequent 41-60 %
Ophiodromus flexuosus 1 1-20 %
Nephtys hystricis 43 41-60 %
Chaetozone setosa 21 41-60 %
Nephrops norvegicus 24 Frequent 61-80 %
Calocaris macandreae 15 Frequent 41-60 %
Jaxea nocturna 1 1-20 %
Callianassa subterranea 6 41-60 %
Pagurus bernhardus 4 41-60 %
Liocarcinus depurator 4 41-60 %
Carcinus maenas 1 21-40 %
Buccinum undatum 2 21-40 %
Mysella bidentata 3 21-40 %
Abra alba 7 21-40 %
Corbula gibba 2 1-20 %
Asterias rubens 2 Rare 21-40 %
Amphiura chiajei 23 41-60 %
Amphiura chiajei 2 Frequent 21-40 %
Lesueurigobius friesii 2 21-40 %
Pomatoschistus minutus 2 21-40 %

Similar biotopes or habitat types

MegMax is found in similar habitats but has reduced numbers of seapens and a wider range of megafauna. It is unclear from the data examined which environmental factors separate these two biotopes although MegMax often occurs in slightly deeper water than SpnMeg.

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