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Marine Habitat Classification

Description of biotope or habitat type

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   Sublittoral mixed sediment in low or reduced salinity (lagoons)

Physical habitat description

Salinity Low (<18ppt)
Wave exposure
Tidal streams Weak (>1 kn)
Substratum Muddy mixed sediment
Zone Infralittoral, Sublittoral fringe
Depth Band 0-5 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.SMx.SMxLS Sublittoral mixed sediment in low or reduced salinity (lagoons)

  • 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.


Shallow, muddy mixed sediments in areas of low or reduced, although stable, salinity (may vary annually) with largely ephemeral faunal communities. Characterised by infaunal oligochaetes, including Baltidrilus costatus and Enchytraeidae, polychaetes such as Hediste diversicolor, Polydora ciliata and Pygospio elegans, bivalves such as Mya arenaria, Abra tenuis, and the lagoon cockle Cerastoderma glaucum as well as surface dwelling snails including Peringia ulvae. Other infauna can vary but can include very high numbers of amphipods Aoridae, Monocorophium insidiosum and other Corophium species, isopods Idotea spp. and seasonally occurring Chironomid larvae. Some sites with higher organic content also have very high numbers of Tubificoides oligochaetes and to a lesser extent Capitella capitata.


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
Enchytraeidae 34 Abundant 61-80%
Hediste diversicolor 31 Frequent 81-100%
Hediste diversicolor 25 Super abundant 61-80%
Baltidrilus costatus 20 Abundant 61-80%
Baltidrilus costatus 17 Frequent 61-80%
Chironomidae 16 Occasional 61-80%
Pomatoschistus microps 14 Common 41-60%
Mya arenaria 6 Super abundant 41-60%
Cerastoderma glaucum 6 Common 21-40%
Pygospio elegans 5 Common 41-60%
Peringia ulvae 4 Common 41-60%
Mya arenaria 4 Rare 41-60%
Palaemon varians 3 Occasional 21-40%
Polydora ciliata 3 Abundant 41-60%
Cerastoderma glaucum 3 Common 41-60%
Lekanesphaera hookeri 2 Occasional 21-40%
Neomysis integer 2 Rare 21-40%
Alkmaria romijni 2 Rare 21-40%
Peringia ulvae 1 Rare 21-40%
Cladophora 1 Rare 21-40%
Corophium volutator 1 41-60%

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.SMx.SMxLS Sublittoral mixed sediment in low or reduced salinity (lagoons)
2004 (04.05) SS.SMx.SMxLS Sublittoral mixed sediment in low or reduced salinity (lagoons)

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