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Marine Habitat Classification

Description of biotope or habitat type

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   Capitella capitata and Tubificoides spp. in reduced salinity infralittoral muddy sediment

Physical habitat description

Salinity Reduced (18-30ppt), Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered, Extremely sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Very weak (negligible)
Substratum Cohesive muddy sediment, sandy mud
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features Possible organic enrichment or physical disturbance

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.SMuVS.CapTubi <I>Capitella capitata</I> and <I>Tubificoides</I> spp. in reduced salinity infralittoral muddy sediment

  • 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.


Reduced or variable salinity muddy sediment characterised by the Capitella capitata species complex with a relatively low species richness. Large numbers of the oligochaetes Tubificoides spp. may be found in conjunction with C. capitata, along with other species such as Marenzellaria sp, Macoma balthica, Arenicola marina and Eteone longa. In some estuaries this biotope may also include high numbers of the polychaete Ophryotrocha. This biotope usually has a moderate organic content, and is found away from tidal channels in estuaries. The presence of dense Capitella has classically been associated with organically enriched and physically disturbed habitats in the marine environment (Warren 1977; Pearson & Rosenberg 1978) and areas of higher organic loads in estuaries will typically fall into the biotope Cap. Where Capitella is less abundant and accompanied by other typical estuarine species the dominance of Capitella may be associated with other natural factors including the occurrence of a competitive refuge for C. capitata in the reduced-salinity environment (Wolff 1973).


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 Typical abundance - (count per m2) % of core records where taxon was recorded
Nematoda 1 2 21-40 %
Eteone longa 2 Common 6 21-40 %
Neanthes virens 1 5 1-20 %
Marenzelleria 7 Common 79 21-40 %
Pygospio elegans 1 5 21-40 %
Capitella capitata 60 Frequent 119 81-100 %
Arenicola marina 3 6 21-40 %
Oligochaeta 3 Frequent 129 41-60 %
Tubificoides benedii 10 Frequent 84 21-40 %
Corophium volutator 1 8 21-40 %
Macoma balthica 4 4 41-60 %

Similar biotopes or habitat types

OlVS can be separated from CapTubi by a swap in the dominant species from C. capitata to Tubificoides spp. and OlVS frequently occurs in lower salinity.

MoMu may contain a similar suite of species to CapTubi although in lower abundance. Only a description of the sediment consistency in the field would allow positive classification

Cap tends to occur in fully marine conditions or in estuarine areas of high organic enrichment and can be distinguished by the reduced species richness as compared to CapTubi.

Classification history of this biotope or habitat type

Classification version Code
97.06 IMU.CapTub

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