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Marine Habitat Classification

Description of biotope or habitat type

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   Capitella capitata in enriched sublittoral muddy sediments

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt), Low (<18ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn)
Substratum Muddy sediment
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features

Biotope origin

Derived using data from Various
Faunal group Infauna

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.ISaMu.Cap <I>Capitella capitata</I> in enriched sublittoral muddy sediments

  • 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.


The polychaete Capitella capitata (agg.) a widely occurring opportunist species complex that is particularly associated with organically enriched and polluted sediments (Warren 1977; Pearson & Rosenberg 1978) where it may be superabundant. In very polluted/disturbed areas only Capitella, nematodes and occasional Malacoceros fuliginosus may be found whilst in slightly less enriched areas and estuaries species such as Tubificoides, Cirriformia tentaculata, Pygospio elegans and Polydora ciliata may also be found. In some areas, e.g. the Tees Estuary and Firth of Clyde, high numbers of the polychaete Ophryotrocha may also be present. SS.SMu.ISaMu.Cap may become established as a result of anthropogenic activities such as fish farming and sewerage effluent but may also occur with natural enrichment as a result of, for example, coastal bird roosts. This biotope may also occur to some extent in the intertidal and in estuaries and have a varied sediment composition; where shell fragments are present then some epifaunal species may occur.


This biotope typically occurs in marine inlets, embayments or estuaries where organic enrichment allows C. capitata to out compete other taxa, although the species may also occur in enriched muddy coastal sediments and also offshore where there is a high organic input from adjacent oil drilling platforms (SS.SMu.OMu.CapThy & SS.SMu.OMu.CapThy.Odub).

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
Capitella capitata 83 Abundant 5155 81-100%
Malacoceros fuliginosus 7 Common 506 61-80%
Tubificoides benedii 3 Frequent 316 21-40%
Nematoda 2 Frequent 201 41-60%
Polydora ciliata 2 329 41-60%
Oligochaeta 1 Common 109 41-60%

Similar biotopes or habitat types

SS.SMu.ISaMu.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 SS.SMu.SMuVS.CapTubi.

Classification history of this biotope or habitat type

Classification version Code Habitat name
2015 (15.03) SS.SMu.ISaMu.Cap Capitella capitata in enriched sublittoral muddy sediments
2004 (04.05) SS.SMu.ISaMu.Cap Capitella capitata in enriched sublittoral muddy sediments
1997 (97.06) SS.IMS.SaMS.Cap Capitella capitata in enriched sublittoral muddy sediments

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