Description of biotope or habitat type
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Cushion sponges and hydroids on turbid tide-swept variable salinity sheltered circalittoral rock
Physical habitat description
| Salinity | Variable (18-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn) |
| Substratum | Bedrock |
| 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 turbid, variable salinity water, on wave-sheltered bedrock in estuaries subject to strong tidal regimes where circalittoral communities occur in relatively shallow water (typically 5m to 8m water depth). Cushion sponges, hydroids and ascidians dominate the biotope. Large growths (often up to 50cm across) of the sponges Halichondria panicea mixed with Halichondria bowerbanki almost entirely cover the bedrock, appearing in places like a continuous cushion. Haliclona oculata, Suberites ficus, Leucosolenia botryoides, various hydroids such as Plumularia setacea, Nemertesia antennina, Nemertesia ramosa and various bryozoans such as Crisularia plumosa, Bugulina turbinata and Amathia pustulosa protude through the Halichondria spp. sponge growth. Colonial ascidians such as the lightbulb ascidian Clavelina lepadiformis and Morchellium argus may also be observed. Other more ubiquitous species include Balanus crenatus, Carcinus maenas, Asterias rubens, Metridium senile, Cylista elegans and Ophiothrix fragilis.
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 |
|---|---|---|---|
| Hymeniacidon perlevis | 11 | Frequent | 61-80% |
| Balanus crenatus | 10 | Common | 41-60% |
| Clavelina lepadiformis | 10 | Frequent | 61-80% |
| Halichondria panicea | 10 | Frequent | 61-80% |
| Suberites ficus | 7 | Occasional | 61-80% |
| Carcinus maenas | 5 | Occasional | 41-60% |
| Asterias rubens | 4 | Occasional | 41-60% |
| Halichondria bowerbanki | 4 | Frequent | 21-40% |
| Plumularia setacea | 4 | Frequent | 41-60% |
| Crisularia plumosa | 3 | Occasional | 41-60% |
| Leucosolenia botryoides | 3 | Frequent | 21-40% |
| Metridium senile | 3 | Occasional | 21-40% |
| Nemertesia antennina | 3 | Frequent | 21-40% |
| Nemertesia ramosa | 2 | Frequent | 21-40% |
| Sagartia troglodytes | 2 | Occasional | 21-40% |
| Amathia pustulosa | 1 | Frequent | 21-40% |
| Bugulina turbinata | 1 | Common | 21-40% |
| Haliclona oculata | 1 | Occasional | 1-20% |
| Morchellium argus | 1 | Occasional | 21-40% |
| Ophiothrix fragilis | 1 | Occasional | 21-40% |
Similar biotopes or habitat types
CR.MCR.CFaVS.CuSpH.As
This sub-biotope occurs in more marine conditions in the outer parts of estuaries. A diverse range of cushion sponges and hydroids are present, unlike CuSp.VS, together with a number of colonial or small solitary ascidians.
