Description of biotope or habitat type
Balanus crenatus and Tubularia indivisa on extremely tide-swept circalittoral rock
Habitat (physical) description
|Salinity||Full (30-35 ppt)|
|Wave exposure||Extremely exposed, Very exposed, Exposed, Moderately exposed, Sheltered, Very sheltered, Extremely sheltered|
|Tidal streams||Very strong (>6 kn), Strong (3-6 kn)|
|Substratum||Bedrock, boulder, cobble|
|Zone||Circalittoral - lower, Circalittoral - upper|
|Depth Band||0-5 m, 5-10 m, 10-20 m, 20-30 m|
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
This biotope typically occurs on upward-facing, extremely tide-swept, circalittoral bedrock, boulders and cobbles found in a broad spectrum of wave-exposures. It is characterised by a few species that are capable of maintaining a foothold in strong tides. These species either form a flat, adherent crust in the case of the barnacle Balanus crenatus, or have strong attachment points and are flexible, bending with the tide, such as the turf of the hydroid Tubularia indivisa. Other species able to tolerate these very strong tides, or just situated slightly out of the main force of the current, include the sponge Halichondria panicea, the robust hydroid Sertularia argentea and current-tolerant anemones such as Sagartia elegans, Urticina felina and Metridium senile. Mobile species such as the starfish Asterias rubens, the crab Cancer pagurus and the whelk Nucella lapillus may also be present.
This biotope is typically occurs in deep, very tide-swept straights, sounds and narrows with a bedrock/boulder/cobble slope. Kelp forest (LhypT) occurs in shallower water.
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||% of core records where taxon was recorded|
|Halichondria panicea||1||Common||21-40 %|
|Tubularia indivisa||18||Frequent||81-100 %|
|Sertularia argentea||5||Frequent||41-60 %|
|Urticina felina||4||Occasional||61-80 %|
|Metridium senile||3||Occasional||41-60 %|
|Sagartia elegans||10||Frequent||61-80 %|
|Balanus crenatus||28||Abundant||81-100 %|
|Cancer pagurus||5||Occasional||61-80 %|
|Nucella lapillus||1||Common||21-40 %|
|Alcyonidium diaphanum||3||Occasional||41-60 %|
|Flustra foliacea||2||Occasional||41-60 %|
|Asterias rubens||7||Occasional||61-80 %|