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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.

   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

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.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 subg. 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
Zostera marina 35 Abundant 61-80%
Chironomidae 28 Abundant 41-60%
Baltidrilus costatus 19 Super abundant 21-40%
Ruppia 13 Common 21-40%
Mysidae 6 Frequent 21-40%
Arenicola marina 5 Occasional 21-40%
Carcinus maenas 5 Occasional 21-40%
Pygospio elegans 4 Frequent 21-40%
Idotea balthica 3 21-40%
Enchytraeidae 3 Common 21-40%
Chorda filum 3 Frequent 21-40%
Tubificoides benedii 3 Frequent 21-40%
Capitella capitata 2 Frequent 21-40%
Ectocarpaceae 2 Frequent 1-20%
Ulva 2 Occasional 1-20%
Hediste diversicolor 2 Super abundant 1-20%
Lanice conchilega 2 Occasional 21-40%
Nematoda 1 Common 1-20%
Anemonia viridis 1 Occasional 21-40%
Asterias rubens 1 Occasional 21-40%
Saccharina latissima 1 Occasional 21-40%
Nemertea 1 Common 21-40%
Pagurus bernhardus 1 Occasional 1-20%

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.SMp.SSgr Sublittoral seagrass beds
2004 (04.05) SS.SMp.SSgr Sublittoral seagrass beds
1997 (97.06) SS.IMS.Sgr Seagrass beds (sublittoral / lower shore)

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