bay exposed to the prevailing winds, much suspended sediment (at least near-shore, close to the seabed) exists. Whilst winds may ease in summer, it is also prone to strong plankton blooms during May and June, with a less pronounced bloom in late summer. Thus underwater visibility rarely exceeds 10 metres (30 ft) and frequently may be less than 3 metres (10 ft). The reefs in the bay, numerous in the centre and east, are mostly discontinuous, forming a patchwork of low rocky outcrops surrounded by sediment. This means that they tend to be covered by thin veneers of sediment as tide and wave action lifts and sweeps saltating sand across them. The amount of sand will vary, depending on the size of the reef, how high it rises above the surrounding sediment plain, the strength of tidal streams in that part of the bay and how strong the wind has been recently (and thus how big the waves). Conversely the reef ecosystems are different from clearer water reefs further west. Wildlife Tank wrecks from the D-Day practice provide a venue for diving. Marine life includes the Devon cup coral (Caryophyllia smithii) and pink sea fan (Eunicella verrucosa) . The pink seafan is a nationally protected species that occurs in very high densities on some of the limestone reefs in Lyme Bay. Reefs in the Eastern part of Lyme Bay support a population of sunset corals (Leptopsammia pruvoti). Sunset corals are one of the very few species of true corals (i.e. stony, or scleractinian, corals found in British waters. Sunset corals are rare in British waters, known to occur at only a handful of locations. The Lyme Bay supports one of the densest populations found around the UK and also the easternmost population known in UK waters. The reefs have been under threat from scallop dredging which, if unregulated, might destroy the coral's habitat. Devon Wildlife Trust has been campaigning to protect the reefs, calling for an end to the dredging and trawling within a zone to help the reefs recover. About 20% of this area is now protected by a voluntary agreement made between the DEFRA and the fishermen of the South West Inshore Fishermen's Association. Settlements Towns and villages marked * fall outside some of the narrower definitions of Lyme Bay. Abbotsbury Axmouth Beer Branscombe Brixham* Budleigh Salterton Charlestown, Dorset Charmouth Dartmouth* Dawlish Warren Exmouth Eype Fortuneswell -and the