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) |
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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.

- 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.
Description
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).
Situation
No situation data available.
Temporal variation
Unknown
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 |
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2015 (15.03) | IR.LIR.K.Lsac |