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Marine Habitat Classification

Description of biotope or habitat type

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   Seapens, including Funiculina quadrangularis, and burrowing megafauna in undisturbed circalittoral fine mud

Physical habitat description

Salinity Full (30-35 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
Other Features Burrows

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.SpnMeg.Fun Seapens, including <I>Funiculina quadrangularis</I>, and burrowing megafauna in undisturbed circalittoral fine 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.


Deep muds, especially in sealochs, support forests of the nationally scarce Funiculina quadrangularis, in addition to populations of the seapens Virgularia mirabilis and Pennatula phosphorea. The sediment is usually extensively burrowed by crustaceans, the most common of which is Nephrops norvegicus, but Calocaris macandreae and Callianassa subterranea may also be present (the latter is likely to be under-recorded by grab sampling because it is deep burrowing). The burrowing anemone Cerianthus lloydii is present in low numbers in this biotope and the rare anemone Pachycerianthus multiplicatus may also be found occasionally. Amphiura spp. are also often present in high densities.


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
Funiculina quadrangularis 23 Frequent 81-100 %
Virgularia mirabilis 10 Occasional 61-80 %
Pennatula phosphorea 14 Frequent 61-80 %
Cerianthus lloydii 8 Occasional 61-80 %
Terebellidae 1 Occasional 21-40 %
Nephrops norvegicus 13 Frequent 61-80 %
Pagurus bernhardus 3 Occasional 41-60 %
Munida rugosa 2 Occasional 41-60 %
Liocarcinus depurator 3 Occasional 41-60 %
Turritella communis 3 Frequent 21-40 %
Aequipecten opercularis 1 Occasional 21-40 %
Asterias rubens 6 Occasional 41-60 %
Amphiura filiformis 3 Abundant 21-40 %

Similar biotopes or habitat types

This biotope is distinguished from SpnMeg by the presence of the nationally scarce seapen Funiculina quadrangularis.

Classification history of this biotope or habitat type

Classification version Code
97.06 CMU.SpMeg.Fun

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