Description of biotope or habitat type
To understand more about what this page is describing, see How to use the classification. See also How to cite.
Modiolus modiolus beds with Mimachlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Boulders, cobbles and shells on muddy sediment |
| Zone | Infralittoral - lower, Circalittoral |
| Depth Band | 5-10 m, 10-20 m, 20-30 m |
| Other Features |
Biotope origin
| Derived using data from | Various |
| Faunal group | Epifauna |
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
Dense Modiolus modiolus beds, covered by hydroids and bryozoans, on soft gravelly, shelly mud with pebbles in areas of slight or moderate tidal currents. The variable scallop (Mimachlamys varia) is frequently found in large numbers amongst the Modiolus shells. Hydroids such as Halecium spp. and Kirchenpaueria pinnata and ascidians such as Ascidiella aspersa, Corella parallelogramma and Ciona intestinalis may be found attached to pebbles or mussel shells. The echinoderms Ophiothrix fragilis and Antedon bifida are often frequent in this biotope as is the encrusting polychaete Spirobranchus triqueter. Similar communities have been found on cobble and pebble plains in stable, undisturbed conditions in some sea lochs, although not all these examples have Modiolus beds.
Situation
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 |
|---|---|---|---|
| Modiolus modiolus | 9 | Common | 81-100% |
| Ophiothrix fragilis | 7 | Frequent | 81-100% |
| Spirobranchus triqueter | 7 | Frequent | 81-100% |
| Antedon bifida | 5 | Frequent | 61-80% |
| Asterias rubens | 5 | Frequent | 81-100% |
| Echinus esculentus | 5 | Occasional | 81-100% |
| Mimachlamys varia | 4 | Occasional | 81-100% |
| Corallinaceae | 3 | Frequent | 41-60% |
| Ascidiella aspersa | 3 | Frequent | 41-60% |
| Buccinum undatum | 3 | Occasional | 81-100% |
| Hyas araneus | 3 | Occasional | 61-80% |
| Liocarcinus depurator | 3 | Occasional | 61-80% |
| Urticina felina | 3 | Occasional | 41-60% |
| Alcyonium digitatum | 2 | Occasional | 61-80% |
| Balanus balanus | 2 | Occasional | 41-60% |
| Cerianthus lloydii | 2 | Occasional | 41-60% |
| Ciona intestinalis | 2 | Occasional | 41-60% |
| Corella parallelogramma | 2 | Occasional | 41-60% |
| Laminaria hyperborea | 2 | Common | 41-60% |
| Ophiocomina nigra | 2 | Occasional | 61-80% |
| Pagurus bernhardus | 2 | Occasional | 41-60% |
| Protula tubularia | 2 | Frequent | 41-60% |
| Aequipecten opercularis | 1 | Occasional | 41-60% |
| Calliostoma zizyphinum | 1 | Occasional | 41-60% |
| Crossaster papposus | 1 | Rare | 41-60% |
| Steromphala cineraria | 1 | Occasional | 41-60% |
| Halecium halecinum | 1 | Frequent | 21-40% |
| Kirchenpaueria pinnata | 1 | Frequent | 41-60% |
| Ophiura albida | 1 | Occasional | 41-60% |
| Phycodrys rubens | 1 | Frequent | 41-60% |
Similar biotopes or habitat types
SS.SBR.SMus.ModHAs
SS.SBR.SMus.ModHAs is less species rich with far fewer sponges and hydroids growing on and amongst the Modiolus and few if any Mimachlamys varia.Classification history of this biotope or habitat type
| Classification version | Code | Habitat name |
|---|---|---|
| 2015 (15.03) | SS.SBR.SMus.ModCvar | Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata |
| 2004 (04.05) | SS.SBR.SMus.ModCvar | Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata |
| 1997 (97.06) | SS.CR.SCR.Mod.ModCvar | Modiolus modiolus beds with Chlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata |
| 1996 (6.95) | SCR.ModSHBy |