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Marine Habitat Classification

Description of biotope or habitat type

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   Sublittoral seagrass beds

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Medium to fine sandy muds
Zone Infralittoral, Sublittoral fringe
Depth Band 0-5 m, 5-10 m
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 SS.SMp.SSgr Sublittoral seagrass beds

  • 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.


Beds of seagrass (Zostera marina or Ruppia spp.) in shallow sublittoral sediments. These communities are generally found in extremely sheltered embayments, marine inlets, estuaries and lagoons, with very weak tidal currents. They may inhabit low, variable and full salinity marine habitats. Whilst generally found on muds and muddy sands they may also occur in coarser sediments, particularly marine examples of Zostera communities.


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
Anemonia viridis 1 Occasional 21-40 %
Nemertea 1 Common 21-40 %
Nematoda 1 Common 1-20 %
Hediste diversicolor 2 Super abundant 1-20 %
Pygospio elegans 4 Frequent 21-40 %
Capitella capitata 2 Frequent 21-40 %
Arenicola marina 5 Occasional 21-40 %
Lanice conchilega 2 Occasional 21-40 %
Heterochaeta costata 19 Super abundant 21-40 %
Tubificoides benedii 3 Frequent 21-40 %
Enchytraeidae 3 Common 21-40 %
Mysidae 6 Frequent 21-40 %
Idotea baltica 3 21-40 %
Pagurus bernhardus 1 Occasional 1-20 %
Carcinus maenas 5 Occasional 21-40 %
Chironomida 28 Abundant 41-60 %
Asterias rubens 1 Occasional 21-40 %
Ectocarpaceae 2 Frequent 1-20 %
Chorda filum 3 Frequent 21-40 %
Laminaria saccharina 1 Occasional 21-40 %
Enteromorpha 2 Occasional 1-20 %
Zostera marina 35 Abundant 61-80 %
Ruppia 13 Common 21-40 %

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
97.06 IMS.Sgr

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