Intertidal mixed sediments

Seashores made of a mixture of stones, gravels, sand and mud

Seashores made of a mixture of stones, gravels, sands and mud © JNCC

Mixed sediments are comprised of unsorted pebbles, gravels, sands and mud, and they may also include rocks and a few large boulders.  This type of shoreline tends to occur in more sheltered locations, and is not found where there is strong wave action.

With such a broad range of seabed types on a single shoreline, the animal and plant communities are very diverse.  Brown and green seaweeds can live on the larger rocks, and barnacles may also be abundant on any hard surfaces. 

Animals living on or in the sand and mud or between the pebbles include many worms such as ragworms, mud shrimps and sandhoppers, cockles and other bivalve shells, as well as the spire shell snail.

This habitat is very vulnerable to physical disturbance such as bait digging as it takes a long time to recover.

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


European distribution

This is an uncommon broad habitat, found at a few scattered sites in the British Isles – in the south-west and north-east of England, East Anglia, west Wales and in north-western Europe.

Seashores made of a mixture of stones, gravels, sands and mud fact


Official habitat definition

EUNIS habitat A2.4 Littoral mixed sediments


Further information

JNCC Marine Habitat Classification

Marine Life Information Network

JNCC EUNIS habitat correlations table