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Exposed sublittoral fringe bedrock with an Alaria esculenta forest and an encrusting fauna of the mussel Mytilus edulis and barnacles such as Semibalanus balanoides. The kelp Laminaria digitata can be part of the canopy. Underneath the canopy are red seaweeds such as Mastocarpus stellatus and Palmaria palmata, while encrusting coralline red algae such as Lithothamnion graciale covers the rock surface. The limpet Patella vulgata can be found grazing the rock surface, while the whelk Nucella lapillus is preying on the limpets, barnacles and mussels. Two variants of this biotope are described. In more wave exposed conditions Laminaria digitata is absent and the rock surface is often characterised by dense patches of mussels (Ala.Myt). In slightly less exposed sites the A. esculenta is mixed with L. digitata (Ala.Ldig).

Very exposed sublittoral fringe bedrock characterised by the kelp Alaria esculenta and dense patches of small individuals of the mussel Mytilus edulis, both of which grow over a dense cover of encrusting coralline algae. Foliose red seaweeds may also be present, but the species composition and their abundance vary between sites. Species such as Corallina officinalis occur widely. The kelp Laminaria digitata is usually absent, although stunted plants may be present at a few sites. The limpet Patella vulgata and the barnacle Semibalanus balanoides are often common. Patches of anthozoans and the hydroid Tubularia spp. occur in more wave-surged areas. In extremely exposed areas the A. esculenta zone can extend as deep as 15 m, where it has less S. balanoides, M. edulis and greater densities of Tubularia spp. (e.g. Barra and shallow areas of Rockall).

Exposed sublittoral fringe bedrock characterised by a mixture of the kelps Laminaria digitata and Alaria esculenta with an understorey of red seaweeds including Palmaria palmata and Corallina officinalis with encrusting coralline algal on the rock surface. Anthozoans such as Halichondria panicea, the mussel Mytilus edulis and the barnacle Semibalanus balanoides can be found attached in cracks and crevices. The limpets Patella vulgata or on southern shores Patella ulyssiponensis can be found in their characteristic "scars" grazing the biofilm/algal crusts on the rock surface, while the limpet Patella pellucida is restricted to grazing the kelp fronds. Colonies of the bryozoan Electra pilosa can cover the red seaweeds Mastocarpus stellatus and Chondrus crispus or the rock surface.