Description of biotope or habitat type
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Caryophyllia smithii, Swiftia pallida and Alcyonium glomeratum on wave-sheltered circalittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Exposed, Moderately exposed, Sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock, boulders |
| Zone | Circalittoral |
| Depth Band | 10-20 m, 20-30 m, 30-50 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 variant typically occurs on sheltered, ridged, circalittoral bedrock or boulders subject to only weak tidal streams, but may be found in somewhat more exposed conditions. It is found in water depths ranging from 15m to 32m. Commonly occurring Swiftia pallida characterises this heavily silted biotope along with Caryophyllia smithii and frequent Alcyonium glomeratum. Under the silt, bryozoan crusts such as Parasmittina trispinosa may be found. There is a strong echinoderm component to the community, with the tentacles of Aslia lefevrei frequently seen protruding from crevices in the ridged bedrock. Holothuria (Panningothuria) forskali is often seen on the upper faces of boulders and bedrock. Marthasterias glacialis, Asterias rubens, Echinus esculentus, Henricia oculata and Luidia ciliaris may also be present. A sparse hydroid turf may also be present, with species such as Schizotricha frutescens, Halecium halecinum and Nemertesia antennina. In addition, there may be anthozoans such as Isozoanthus sulcatus and Corynactis viridis. The sponge Suberites carnosus is typically associated with a heavily silted habitat. Other sponges present include Cliona celata, Stelligera stuposa and Polymastia boletiformis. The only records are from the west coast of Ireland.
Situation
Usually found on bedrock ridges and outcrops surrounded by sand and muddy gravel.
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 |
|---|---|---|---|
| Caryophyllia smithii | 12 | Common | 81-100% |
| Swiftia pallida | 11 | Common | 81-100% |
| Aslia lefevrei | 8 | Frequent | 81-100% |
| Suberites carnosus | 8 | Occasional | 81-100% |
| Cliona celata | 6 | Occasional | 81-100% |
| Holothuria (Panningothuria) forskali | 6 | Occasional | 81-100% |
| Alcyonium glomeratum | 6 | Frequent | 81-100% |
| Asterias rubens | 5 | Occasional | 81-100% |
| Marthasterias glacialis | 5 | Occasional | 81-100% |
| Isozoanthus sulcatus | 4 | Occasional | 61-80% |
| Luidia ciliaris | 4 | Occasional | 61-80% |
| Schizotricha frutescens | 4 | Frequent | 61-80% |
| Echinus esculentus | 4 | Frequent | 61-80% |
| Halecium halecinum | 2 | Occasional | 41-60% |
| Henricia oculata | 2 | Occasional | 61-80% |
| Parasmittina trispinosa | 2 | Occasional | 41-60% |
| Polymastia boletiformis | 2 | Occasional | 41-60% |
| Stelligera stuposa | 2 | Occasional | 41-60% |
| Corynactis viridis | 1 | Occasional | 41-60% |
| Nemertesia antennina | 1 | Occasional | 41-60% |
Similar biotopes or habitat types
CR.MCR.EcCr.CarSwi.LgAs
This biotope is found over a broad range of sites with different wave-exposures, subject to moderately strong to very weak tidal streams. The substratum is typically similar to CR.MCR.EcCr.CarSwi.Aglo, but CR.MCR.EcCr.CarSwi.LgAs has a lower diversity of sponges and hydroids.
CR.HCR.XFa.SwiLgAs
This biotope occurs in slightly more wave-exposed and more tide-swept sites than CR.MCR.EcCr.CarSwi.Aglo. They both occur across similar depth bands. CR.HCR.XFa.SwiLgAs appears a lot more biologically diverse, with a greater range of sponges, hydroids, bryozoans and ascidians.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | CR.MCR.XFa.ErSSwi |