Moderate energy intertidal rock

Rocky seashores, with some shelter from waves and currents

Rocky seashore, with some shelter from waves and currents © JNCC

The movement of the sea across moderate energy rocky shores is strong enough to prevent much sand or mud accumulating, but these shores are not subject to the full forces of the waves and tides, so many different seashore animals and seaweeds live here.

On these shores, there are places where plants and animals can find shelter from the waves – the landward sides of boulders, in cracks and crevices, and in rock pools.  Brown seaweeds are usually common everywhere on the shore, with different species occupying different zones according to how long they spend uncovered by the tide.  They do not, however, form such complete blanket coverage as is the case on more sheltered rocky shores.  Red seaweeds are also found on the lower shore, where they are only exposed to the air for relatively short periods.  Where freshwater streams cross the shore or the rock is scoured as sand is washed across it, the seaweed communities will tend to be dominated by red and green seaweeds, which come and go.  

Barnacles and blue mussels are common on these rocky shores, as are limpets, whelks and periwinkles.

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

 

European distribution

Moderately exposed rocky and boulder shores are found on the south-west and west coasts of Britain, 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 coastlines, where there are rocky cliffs.

Rockpool Fact

 

Official habitat definition

EUNIS habitat A1.2 Moderate energy littoral rock

 

Further information

JNCC Marine Habitat Classification

JNCC EUNIS habitat correlations table