Moderate energy circalittoral rock

Deeper water rock, with some shelter from waves and currents

Seaweeds tend to dominate shallow coastal areas, but as the water depth increases and there is insufficient sunlight for seaweed growth, animal communities are able to prevail.

The types of animals that live in this zone vary enormously.  The strength of the waves and the speed of the tidal stream are two important factors that affect where the different animals set up home.

Where bedrock and boulder seascapes are affected by moderate wave action and fairly strong tidal streams, the animal communities can include cup coral, sea-fans, and anemones, or they may be dominated by sponges.  Mobile animals in this environment include starfish, brittlestars, and sea urchins.  It is also possible to find rock borers and piddocks, which are both types of bivalves (with paired, hinged shells) that burrow into soft rocks such as limestone. 

Mussel beds and worm reefs can also occur in the moderate wave and tide environment of these rocky areas.

For the official habitat definition please see the documents listed below.


European distribution

On exposed rocky headlands and coastlines, mainly on the south-west and west coasts of Britain and Ireland, where they are exposed to the prevailing south-westerly wind.


Official habitat definition

EUNIS habitat A4.2 Atlantic and Mediterranean moderate energy circalittoral rock


Further information

JNCC Marine Habitat Classification

JNCC EUNIS habitat correlations table

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