The Atol das Rocas Biological Reserve, the only atoll in the South Atlantic, is located about 150 km west of Fernando de Noronha. The Rocas Atoll has a spectacular seascape, especially at low tide when the exposed reef surrounding shallow lagoons and tidal pools forms a natural aquarium. Criterion (ix): The Fernando de Noronha and Atol das Rocas represents over half the insular coastal waters of the Southern Atlantic Ocean. Criterion (x): The Fernando de Noronha and Rocas Atoll are key sites for the protection of biodiversity and endangered species in the Southern Atlantic. The site has two separate management plans, one for Fernando de Noronha and the other for Rocas Atoll.