Underwater rock surfaces are very often completely smothered in an animal ‘turf’ of sea mats, hydroids, sponges and anemones. Species vary depending on the water depth, topography of the rock, which direction it faces, wave and tide exposure, and the type of rock (geology). Limestone reefs found off the south Pembrokeshire coast for example have a softer rock surface that can be pitted and contain cracks and crevices for animals to live in. Some animals can even bore into the rock.
Living amongst these sedentary reef species are mobile animals such as lobsters, starfish, sea slugs, sea urchins and territorial fish such as sex-changing wrasse.
As well as extensive areas of underwater rocky reef stretching offshore from the wild open coast, rocky reefs can also be found throughout the more sheltered environment of the Milford Haven waterway. Finding large amounts of rocky reef far upstream is one of the waterway’s special and unusual characteristics. Intertidal reef covers much of the shoreline within the site (offering plenty of opportunities for exciting rock pooling!).