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Marine Habitat Classification

Description of biotope or habitat type

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   Ruppia maritima in reduced salinity infralittoral muddy sand

Physical habitat description

Salinity Reduced (18-30ppt)
Wave exposure Extremely sheltered
Tidal streams Very weak (negligible)
Substratum Muddy fine sand to mud
Zone Infralittoral
Depth Band 0-5 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.Rup <I>Ruppia maritima</I> in reduced salinity infralittoral muddy sand

  • 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.


In sheltered brackish muddy sand and mud, beds of Ruppia maritima and more rarely Ruppia spiralis may occur. These beds may be populated by fish such as Gasterosteus aculeatus which is less common on filamentous algal-dominated sediments. Seaweeds such as Chaetomorpha spp., Ulva spp., Cladophora spp., and Chorda filum are also often present in addition to occasional fucoids. In some cases, the stoneworts Lamprothamnium papulosum and Chara aspera can occur. Infaunal and epifaunal species may include mysid crustacea, the polychaete Arenicola marina, the gastropod Peringia ulvae, the amphipod Corophium volutator and oligochaetes such as Baltidrilus costatus. In some areas Zostera subg. Zostera marina may also be interspersed with the Ruppia beds.


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
Ruppia 43 Abundant 61-80%
Chironomidae 43 Abundant 61-80%
Baltidrilus costatus 27 Super abundant 61-80%
Mysidae 13 Frequent 41-60%
Corophium volutator 12 Abundant 41-60%
Arenicola marina 5 Occasional 21-40%
Carcinus maenas 4 Occasional 21-40%
Idotea balthica 3 21-40%
Enchytraeidae 3 41-60%
Filamentous green algae 3 Frequent 21-40%
Gasterosteus aculeatus 3 Rare 21-40%
Ruppia maritima 2 Abundant 1-20%
Gammarus zaddachi 2 1-20%
Lamprothamnium papulosum 2 Frequent 21-40%
Chaetomorpha linum 2 Occasional 21-40%
Ectocarpaceae 2 Occasional 21-40%
Ulva 2 Occasional 21-40%
Ulva intestinalis 2 Frequent 21-40%
Hediste diversicolor 2 Super abundant 21-40%
Pygospio elegans 2 Abundant 21-40%
Zostera marina 1 1-20%
Capitella capitata 1 21-40%
Gammarus locusta 1 21-40%

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.Rup Ruppia maritima in reduced salinity infralittoral muddy sand
2004 (04.05) SS.SMp.SSgr.Rup Ruppia maritima in reduced salinity infralittoral muddy sand
1997 (97.06) SS.IMS.Sgr.Rup Ruppia maritima in reduced salinity infralittoral muddy sand

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