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Marine Habitat Classification

Description of biotope or habitat type

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   Polydora sp. tubes on moderately exposed sublittoral soft rock

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Moderately exposed
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Bedrock (soft)
Zone Circalittoral, Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m, Lower shore
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 CR.MCR.SfR.Pol <I>Polydora</I> sp. tubes on moderately exposed sublittoral soft rock

  • 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 patches of chalk and soft limestone are occasionally covered entirely by Polydora sp. tubes to the exclusion of almost all other species. This tends to occur in highly turbid conditions and spans the infralittoral and circalittoral in limestone areas such as the Great and Little Ormes (North Wales) and Gower (South Wales). It is even present on the lower shore in the Severn estuary. The boring form of the sponge Cliona celata often riddles the surface layer of the stone. Other sponges present include Halichondria panicea, Haliclona oculata and Hymeniacidon perlevis. Polydora sp. also frequently occurs in small patches as part of other biotopes (e.g. FluCoAs). Other species present include Alcyonium digitatum, Rolandia coralloides, the hydroids Halecium halecinum, Abietinaria abietina and Tubularia indivisa, the ascidians Clavelina lepadiformis, Botryllus schlosseri and Morchellium argus, the anemones Urticina felina, Metridium senile and Cylista elegans and the bryozoans Flustra foliacea and a crisiid turf. The starfish Asterias rubens, the crabs Inachus phalangium and Carcinus maenas, the polychaete Spirobranchus triqueter, the barnacle Balanus crenatus and the brittlestar Ophiothrix fragilis may also be seen. Please note: this biotope may extend into the infralittoral and littoral zone in areas where water turbidity is sufficiently high.


No situation data available.

Temporal variation

Not known.

Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Polydora 25 Abundant 81-100%
Alcyonium digitatum 8 Common 61-80%
Urticina felina 6 Occasional 61-80%
Halecium halecinum 5 Frequent 41-60%
Asterias rubens 4 Frequent 41-60%
Flustra foliacea 4 Frequent 41-60%
Clavelina lepadiformis 3 Occasional 61-80%
Halichondria panicea 3 Frequent 41-60%
Botryllus schlosseri 2 Occasional 41-60%
Haliclona oculata 2 Occasional 61-80%
Inachus phalangium 2 Occasional 41-60%
Metridium senile 2 Frequent 41-60%
Morchellium argus 2 Frequent 41-60%
Ophiothrix fragilis 2 Occasional 41-60%
Rolandia coralloides 2 Common 41-60%
Abietinaria abietina 1 Frequent 21-40%
Balanus crenatus 1 Frequent 21-40%
Carcinus maenas 1 Frequent 21-40%
Cliona celata 1 Occasional 61-80%
Crisiidae 1 Common 21-40%
Hymeniacidon perlevis 1 Occasional 41-60%
Spirobranchus triqueter 1 Occasional 41-60%
Cylista elegans 1 Frequent 41-60%
Tubularia indivisa 1 Frequent 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
1997 (97.06) CR.MCR.SfR.Pol


CR.MCR.SFR.Pol Polydora sp. tubes on moderately exposed sublittoral soft rock, E of Marshall Meadows, Berwick. Keith Hiscock© JNCC
CR.MCR.SFR.Pol Polydora sp. tubes on moderately exposed sublittoral soft rock, E of Marshall Meadows, Berwick. Keith Hiscock© JNCC

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