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Marine Habitat Classification

Description of biotope or habitat type

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   Sublittoral mud in low or reduced salinity (lagoons)

Physical habitat description

Salinity Reduced (18-30ppt), Low (<18ppt)
Wave exposure Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Mud and sandy mud
Zone Infralittoral, Sublittoral fringe
Depth Band 0-5 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.SMu.SMuLS Sublittoral mud 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, typically anoxic, muddy and sandy mud sediments in areas of low or reduced, although stable, salinity (may vary annually) with largely ephemeral faunal communities. Characterised by Arenicola marina and blue-green algae with other species, including mysids, Carcinus maenas and Corophium volutator which commonly occur in lagoons. Important infaunal species may include Hediste diversicolor, Heterochaeta costata and chironomids; however infaunal records for this biotope are limited.


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
Hediste diversicolor 44 Abundant 61-80 %
Pygospio elegans 3 41-60 %
Arenicola marina 45 Frequent 41-60 %
Heterochaeta costata 34 Abundant 61-80 %
Mysidae 13 Frequent 21-40 %
Corophium volutator 8 Frequent 21-40 %
Crangon crangon 8 Occasional 21-40 %
Carcinus maenas 8 Occasional 21-40 %
Chironomida 15 Common 61-80 %
Hydrobia ulvae 1 Common 21-40 %
Hydrobia ulvae 3 Occasional 21-40 %
Ruppia 4 Occasional 21-40 %

Similar biotopes or habitat types

Not applicable or unknown.

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