Rocky habitats in the infralittoral zone subject to exposed to extremely exposed wave action or strong tidal streams. Typically the rock supports a community of kelp Laminaria hyperborea with foliose seaweeds and animals, the latter tending to become more prominent in areas of strongest water movement (A3.113, A3.115 and A3.1152). The depth to which the kelp extends varies according to water clarity, exceptionally (e.g. St Kilda) reaching 45 m. In some areas, there may be a band of dense foliose seaweeds (reds or browns) below the main kelp zone (A3.116). The sublitttoral fringe is characterised by dabberlocks Alaria esculenta (A3.111). In very strong wave action the sublittoral fringe A. esculenta zone extends to 5 to 10 m depth, whilst at Rockall A. esculenta replaces L. hyperborea as the dominant kelp in the infralittoral zone (A3.112). Situation: Very exposed rocky coasts, from low water to depths up to 45m. Temporal variation: Winter storms may remove patches of kelp, and fast-growing annuals may form a temporary forest (A3.122).