Description of biotope or habitat type
Mytilus edulis beds with hydroids and ascidians on tide-swept exposed to moderately wave-exposed circalittoral rock
Habitat (physical) description
|Salinity||Full (30-35 ppt)|
|Wave exposure||Extremely exposed, Exposed|
|Tidal streams||Strong (3-6 kn), Moderately strong (1-3 kn)|
|Substratum||Bedrock, shells, pebbles, gravel|
|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 the upper faces of tide-swept circalittoral bedrock, boulders and mixed substrata exposed to varying amounts of wave action. The mussel Mytilus edulis forms dense beds, to the exclusion of other species. The starfish Asterias rubens is frequently recorded, and it predates heavily on the mussels. Occasionally, the anemone Urticina felina may be seen within crevices in the rock or on gravel patches. Crabs such as Necora puber and Carcinus maenas may be seen on the rock or mussels whilst fauna observed in crevices typically consists of the lobster Homarus gammarus and the crab Cancer pagurus. The anemone Sargatia elegans can be seen attached to bedrock and cobbles, whereas the barnacle Balanus crenatus may be seen attached to the mussels themselves.
No situation data available.
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||% of core records where taxon was recorded|
|Urticina felina||8||Occasional||61-80 %|
|Sagartia elegans||3||Occasional||41-60 %|
|Balanus crenatus||1||Frequent||21-40 %|
|Homarus gammarus||1||Rare||21-40 %|
|Cancer pagurus||3||Rare||41-60 %|
|Necora puber||4||Occasional||41-60 %|
|Carcinus maenas||3||Common||21-40 %|
|Mytilus edulis||58||Abundant||81-100 %|
|Asterias rubens||12||Frequent||61-80 %|