Moderate energy infralittoral rock

Shallow water rock, below the tides, with some shelter from waves and currents

Shallow water rock, below the tides, with some shelter from waves and currents © Lin Baldock

Where rocky cliffs and boulder seascapes are found in areas of moderate wave action and fairly benign tidal currents, the marine life is dominated by seaweeds, which will extend as far below the surface as the penetration of sunlight allows. 

In shallow underwater areas, the top of which may be exposed on the lowest tides, there is often a narrow band of oarweed above a forest of tangle kelp.  These large seaweeds provide a home for all sorts of small marine creatures, which shelter and feed amongst the leaf-like fronds and within the holdfast by which the kelp attaches to the seabed.

Amongst and below the kelp are different kinds of red seaweed, including more of the delicate thread-like seaweeds that cannot colonise areas with stronger waves or tides.  The red seaweeds are grazed by animals including top shells, sea urchins and sea slugs.

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

 

European distribution

Exposed rocky and boulder shores are found on the south-west and west coasts of Britain and Ireland, where they are exposed to the prevailing south-westerly wind.  They are also found on the north-east English coast.  In mainland Europe, they are associated with south and west facing headlands and rocky coastlines.

Slightly sheltered shallow water rock fact

 

Official habitat definition

EUNIS habitat A3.2 Atlantic and Mediterranean moderate energy infralittoral rock

 

Further information

JNCC Marine Habitat Classification

JNCC EUNIS habitat correlations table