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.
Cushion sponges, hydroids and ascidians on turbid tide-swept sheltered circalittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Bedrock, boulders |
| Zone | Circalittoral |
| Depth Band | 0-5 m, 5-10 m, 10-20 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.
- 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
This sub-biotope typically occurs in a mixture of turbid, full and variable salinity water, on wave-sheltered and moderately exposed bedrock or boulders. Tidal streams are typically moderately strong but may vary considerably. This sub-biotope occurs in relatively shallow water (typically 5m to 11m water depth) and is dominated by cushion sponges, hydroids and ascidians. On the silty, rocky substrata, large growths of sponge are usually associated with this biotope (Suberites ficus, Hymeniacidon perlevis, Cliona celata, Halichondria panicea, Raspailia ramosa). The tasselled form of Amphilectus fucorum is also notably present. Other epifauna present includes silty hydroids such as Nemertesia antennina, Nemertesia ramosa, Plumularia setacea, Hydrallmania falcata and Halecium halecinum. Individual colonies of dead mans fingers Alcyonium digitatum and plumose anemones Metridium senile may be seen attached to the tops of boulders and ridges. At some sites, whole sides of rocks may be colonised by the anemones Cylista elegans, Sagartia troglodytes and Actinothoe sphyrodeta. Within crevices in the rocky substratum and at the base of boulders Urticina felina and Cereus pedunculatus may be found. Ascidians such as Clavelina lepadiformis, Morchellium argus, Dendrodoa grossularia, Diplosoma listerianum and Distomus variolosus may all be observed. Other ubiquitous species which may be recorded include Polydora, terebellid worms, Balanus crenatus, Alcyonidium diaphanum and Asterias rubens.
Situation
No situation data available.
Temporal variation
Not known.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Suberites ficus | 10 | Frequent | 81-100% |
| Nemertesia antennina | 7 | Frequent | 61-80% |
| Clavelina lepadiformis | 5 | Occasional | 61-80% |
| Hymeniacidon perlevis | 5 | Occasional | 61-80% |
| Morchellium argus | 4 | Occasional | 61-80% |
| Alcyonium digitatum | 3 | Occasional | 41-60% |
| Cliona celata | 3 | Occasional | 61-80% |
| Halichondria panicea | 3 | Frequent | 41-60% |
| Metridium senile | 3 | Frequent | 41-60% |
| Nemertesia ramosa | 3 | Occasional | 41-60% |
| Plumularia setacea | 3 | Occasional | 41-60% |
| Urticina felina | 3 | Frequent | 41-60% |
| Actinothoe sphyrodeta | 2 | Occasional | 41-60% |
| Balanus crenatus | 2 | Frequent | 21-40% |
| Cereus pedunculatus | 2 | Occasional | 41-60% |
| Dendrodoa grossularia | 2 | Frequent | 41-60% |
| Amphilectus fucorum | 2 | Frequent | 41-60% |
| Polydora | 2 | Common | 41-60% |
| Seraphsidae | 2 | Frequent | 41-60% |
| Alcyonidium diaphanum | 1 | Occasional | 21-40% |
| Asterias rubens | 1 | Occasional | 41-60% |
| Diplosoma listerianum | 1 | Rare | 41-60% |
| Distomus variolosus | 1 | Frequent | 21-40% |
| Halecium halecinum | 1 | Occasional | 41-60% |
| Hydrallmania falcata | 1 | Occasional | 41-60% |
| Raspailia ramosa | 1 | Occasional | 41-60% |
| Cylista elegans | 1 | Occasional | 41-60% |
| Sagartia troglodytes | 1 | Frequent | 21-40% |
Similar biotopes or habitat types
CR.MCR.CFaVS.HbowEud
This biotope occurs on reduced salinity circalittoral bedrock and boulders subject to strong to weak tidal streams. Verylimited species diversity, unlike CR.MCR.CFaVS.CuSpH.As.