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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.

   Serpula vermicularis reefs on very sheltered infralittoral muddy sand

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 Calcareous tubes; pebbles; shells; gravel on sandy mud
Zone Infralittoral - lower, Circalittoral
Depth Band 0-5 m, 5-10 m, 10-20 m, 20-30 m
Other Features

Biotope origin

Derived using data from Various
Faunal group Epifauna

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.SBR.PoR.Ser <I>Serpula vermicularis</I> reefs on very sheltered infralittoral muddy sand

  • 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.


Large clumps (mini 'reefs') of the calcareous tubes of Serpula vermicularis, typically attached to stones on muddy sediment in very sheltered conditions in sea lochs and other marine inlets. A rich associated biota attached to the calcareous tube may include Amphilectus fucorum, thin encrusting sponges, and the ascidians Ascidiella aspersa, Ascidia mentula, Dendrodoa grossularia and Diplosoma listerianum. The echinoderms Ophiothrix fragilis and Psammechinus miliaris and the queen scallop (Aequipecten opercularis) are also found throughout this biotope. In shallow water dense Phycodrys rubens may grow on the 'reefs'. This biotope has been recorded in the U.K. from Loch Creran, where these reefs have been well studied (Moore 1996), and Loch Sween, where they are reported to have deteriorated. The only other known sites for this biotope are Salt Lake, Cliffden and Killary Harbour, Co. Galway.


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
Serpula vermicularis 25 Common 81-100%
Psammechinus miliaris 16 Frequent 81-100%
Ophiothrix fragilis 8 Occasional 81-100%
Ascidiella aspersa 5 Frequent 61-80%
Aequipecten opercularis 4 Occasional 61-80%
Asterias rubens 4 Occasional 61-80%
Pagurus bernhardus 4 Occasional 61-80%
Ascidia mentula 3 Rare 61-80%
Dendrodoa grossularia 3 Common 41-60%
Spirobranchus triqueter 3 Common 41-60%
Corallinaceae 2 Occasional 41-60%
Buccinum undatum 2 Occasional 41-60%
Carcinus maenas 2 Rare 61-80%
Diplosoma listerianum 2 Frequent 41-60%
Amphilectus fucorum 2 Frequent 41-60%
Steromphala cineraria 2 Occasional 41-60%
Phycodrys rubens 2 Occasional 41-60%
Ciona intestinalis 1 Occasional 41-60%
Corella parallelogramma 1 Frequent 41-60%
Lithothamnion glaciale 1 Occasional 21-40%
Nemertesia antennina 1 Occasional 41-60%
Sabella pavonina 1 Occasional 41-60%

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.SBR.PoR.Ser Serpula vermicularis reefs on very sheltered circalittoral muddy sand
2004 (04.05) SS.SBR.PoR.Ser Serpula vermicularis reefs on very sheltered circalittoral muddy sand
1997 (97.06) SS.CMS.Ser Serpula vermicularis reefs on very sheltered circalittoral muddy sand
1996 (6.95) SCR.Sver

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