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Marine Habitat Classification

Description of biotope or habitat type

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   Laminaria saccharina and Chorda filum on sheltered upper infralittoral muddy sediment

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Sandy mud and gravel
Zone Infralittoral - upper, 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.KSwSS.LsacCho <I>Laminaria saccharina</I> and <I>Chorda filum</I> on sheltered upper infralittoral muddy sediment

  • 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 kelp community found on sandy mud and gravelly sandy mud, in sheltered or extremely sheltered conditions, with very weak tidal currents. The community is characterised by a reasonable covering of Laminaria saccharina and Chorda filum. Beneath the kelp canopy, Ulva lactuca is often frequent and some filamentous and foliose red algae may be present, along with filamentous brown ectocarpoid algae although in much lower abundance than in the LsacR biotopes. At the sediment surface ubiquitous fauna such as Asterias rubens, crabs such as Pagurus bernhardus, Carcinus maenas, and the gastropod Gibbula cineraria may be visable and in some areas Sabella pavonina may be present. Given the nature of the sediment it is likely that a wide range of infaunal bivalves and polychaetes are present including Arenicola marina, Mediomastus fragilis and Anaitides mucosa. In more tideswept areas with coarser and generally less muddy sediments SMP.LsacCho may be replaced by one of the sub biotopes of SMP.LsacR.


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
Hydractinia echinata 3 Occasional 41-60 %
Anaitides mucosa 50 81-100 %
Mediomastus fragilis 50 81-100 %
Arenicola marina 5 Frequent 41-60 %
Balanus crenatus 1 Occasional 21-40 %
Pagurus bernhardus 5 Occasional 41-60 %
Liocarcinus depurator 2 Occasional 21-40 %
Carcinus maenas 9 Occasional 61-80 %
Gibbula cineraria 2 Occasional 21-40 %
Buccinum undatum 2 Occasional 21-40 %
Asterias rubens 4 Occasional 41-60 %
Ascidiella aspersa 2 Frequent 21-40 %
Polyides rotundus 2 Occasional 21-40 %
Chorda filum 18 Frequent 81-100 %
Laminaria saccharina 23 Frequent 81-100 %
Enteromorpha 1 Occasional 21-40 %
Ulva 3 Occasional 21-40 %

Similar biotopes or habitat types

Not applicable or unknown.

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