Subtidal sandbanks

This habitat feature consists of soft sediment types that are permanently covered by shallow sea water (generally less than 20m deep). The species found in this habitat type vary according to the sediment type and local physical conditions. Dunes, waves and ripples are important sandbank micro-niches.

There are several major sandbanks within the SAC, including Bais Bank, Turbot Bank, sandbanks in the vicinity of Skokholm (Wild Goose Race and The Knoll), and sandbanks associated with Grassholm Island. There are also deeper sandbanks associated with the Bishops & Clerks, Hats & Barrels and St Govan’s Shoals reefs and in the north-west and south-west of St Bride’s Bay.

Each sandbank is unique and has its own characteristic communities of species. Shallow sandy sediments are typically colonised by burrowing animals such as worms, crustaceans, bivalve shells, and echinoderms (starfish and urchins). Prawns, crabs, snails and fish (such as sand eels – an important food for birds) may live on the surface. These banks can be important nursery areas for fish and feeding grounds for seabirds. The deeper more stable sandbanks tend to be richer in species than the more mobile, exposed and shallow sandbanks.