WEBduring an 8 month visit to Peros Banhos and Salomon atolls in the North of the Chagos Archipelago. Three main lines of study were: (1) Coral cover and definition of coral zones to 45 m in detail and 60 m in brief on seaward slopes of both atolls and to lagoon floor in Peros Banhos; (2) diversity with depth, both within and