Fernando de Noronha is an archipelago of 20 islands located 200 nautical miles off the northeast coast of Brazil from Natal. The islands are of volcanic origin and emerge from a depth of 4000 meters. With an air temperature of 85 degrees and a water temperature of 80 degrees, Fernando de Noronha is the best site for scuba diving in Brazil. Underwater visibility extends up to 50 meters. The largest residential school of dolphins on earth makes Fernando de Noronha its home. Prolific marine life is also found in this area (pelagic fishes such as sharkes, tuna, jack, albacore, and benthic fishes such as gigantic jewfishes, groupers and snappers). The region is also known for harbouring enormous marine–bird colonies, which when least expected, swoop down and dive deep into the water looking for fish.