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Marine Habitat Classification

Description of biotope or habitat type

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   Saccharina latissima on very sheltered infralittoral rock

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Very sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; boulders
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 m, 20-30 m
Other Features Silty

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 IR.LIR.K.Slat <I>Saccharina latissima</I> on very sheltered infralittoral rock

  • 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.


Very sheltered infralittoral rock dominated by the kelp Saccharina latissima. Typically very silty and often with few associated seaweeds due to siltation, grazing or shading from the dense kelp canopy. The most commonly occurring red seaweeds are Delesseria sanguinea, Phycodrys rubens, Bonnemaisonia hamifera and coralline crusts. In addition to the kelp the brown seaweed Chorda filum and Ectocarpaceae are often present. As well as lacking Laminaria hyperborea, the Lsac biotopes have fewer foliose and filamentous red seaweed species by comparison to LhypLsac biotopes. A depauperate assemblage of animals is present (by comparison to Lhyp.Ft and Lhyp.Pk) predominantly consisting of the encrusting polychaetes Spirobranchus triqueter, the crabs Carcinus maenas and Pagurus bernhardus and the ubiquitous gastropod Steromphala cineraria. The echinoderms Antedon bifida, starfish Asterias rubens, brittlestar Ophiothrix fragilis and urchin Echinus esculentus occur in low abundance. Ascidians are commonly found in all the Lsac biotopes, but the large solitary ascidian Ascidia mentula are most prolific in very sheltered conditions of L. saccharina forests (Lsac.Ft). This biotope is most commonly associated with the sheltered fjordic sealochs of Scotland where sublittoral hard substrata can be found at the sheltered head of the lochs. Similarly the sheltered loughs of Ireland (Lough Hyne, Strangford Lough and Carlingford Lough). It is also found where suitable hard substrata exist in the sheltered inlets of south-west Britain, such as Milford Haven or Plymouth Sound. 4 variants has been described: A mixture of L. saccharina and Laminaria digitata (Lsac.Ldig), dense L. saccharina forest in the upper infralittoral (Lsac.Ft), sparse L. saccharina in the lower infralittoral (Lsac.Pk) and urchin-grazed (Lsac.Gz).


No situation data available.

Temporal variation


Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Saccharina latissima 30 Common 81-100%
Corallinaceae 8 Frequent 41-60%
Asterias rubens 5 Occasional 41-60%
Steromphala cineraria 4 Occasional 41-60%
Spirobranchus triqueter 4 Frequent 41-60%
Echinus esculentus 4 Occasional 41-60%
Chorda filum 3 Occasional 41-60%
Phycodrys rubens 3 Frequent 21-40%
Ascidia mentula 2 Occasional 21-40%
Carcinus maenas 2 Occasional 21-40%
Pagurus bernhardus 2 Occasional 21-40%
Bonnemaisonia hamifera 1 Frequent 21-40%
Clavelina lepadiformis 1 Occasional 21-40%
Delesseria sanguinea 1 Occasional 21-40%
Ectocarpaceae 1 Frequent 21-40%
Ophiothrix fragilis 1 Occasional 21-40%
Ulva lactuca 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
2015 (15.03) IR.LIR.K.Lsac

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