Description of biotope or habitat type
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Mussels and fucoids on moderately exposed shores
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Exposed, Moderately exposed |
| Tidal streams | |
| Substratum | Bedrock; large boulders |
| Zone | Eulittoral - lower, Eulittoral - mid |
| Depth Band | |
| 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.
- 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'
Point data based on records in the UK Marine Recorder Snapshot.
Description
Mid and lower eulittoral exposed to moderately exposed bedrock, often with nearby sediment, may be densely covered by large individuals of the mussel Mytilus edulis. Three biotopes have been described: In the mid eulittoral, the mussels may form a band or large patches with scattered bladder wrack Fucus vesiculosus (MytFves). In the lower eulittoral a range of red seaweeds including Mastocarpus stellatus and Palmaria palmata occur amongst the mussels (in higher abundance than the mid eulittoral) (MytFR). Clay outcrops in the mid to lower eulittoral may be bored by a variety of piddocks including Pholas dactylus, Barnea candida and Petricolaria pholadiformis, while the surface is characterised by small clumps of the mussel M. edulis, the barnacle Austrominius modestus and the winkle Littorina littorea (MytPid). Ephemeral green seaweeds such as Ulva intestinalis and Ulva lactuca commonly occur on the shells of the mussels. Barnacles are common on both the mussel valves and on patches of bare rock, where the limpet Patella vulgata is found as well, often at high abundance. The whelk Nucella lapillus and a range of littorinids also occur within the mussel bed. A dense M. edulis community may be found on more sheltered coasts on mixed substrata (Myt).
Situation
Above this biotope complex is a M. edulis and S. balanoides dominated zone (MF) or a F. vesiculosus dominated biotope (FvesB). In the lower eulittoral zone below is a zone dominated by the wrack Fucus serratus, M. edulis and a variety of red seaweeds (BF) while kelp dominate the sublittoral fringe.
Temporal variation
No temporal variation data available.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Mytilus edulis | 30 | Abundant | 81-100% |
| Semibalanus balanoides | 12 | Common | 81-100% |
| Patella vulgata | 7 | Frequent | 61-80% |
| Nucella lapillus | 7 | Frequent | 61-80% |
| Ulva intestinalis | 5 | Frequent | 41-60% |
| Littorina littorea | 4 | Frequent | 41-60% |
| Fucus vesiculosus | 4 | Common | 21-40% |
| Fucus serratus | 3 | Common | 41-60% |
| Mastocarpus stellatus | 3 | Frequent | 41-60% |
| Ulva lactuca | 3 | Occasional | 41-60% |
| Corallinaceae | 2 | Occasional | 41-60% |
| Palmaria palmata | 2 | Frequent | 41-60% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | MLR.MF |
| 1996 (6.95) | MLR.Myt |