Shark evacuation from Mo’orea island in 2002

Reef sharks, including blackfins (Carcharhinus melanopterus) reside in the lagoons and on the outer slopes of the barrier reefs of Mo’orea Island, French Polynesia. In general the lagoons are shallow enough to permit underwater observation, while dive clubs hold shark dives at different sites in the lagoons and in the ocean. Thus, the presence of blackfin sharks especially, and other species at times, is confirmed daily. Between about 21 July and 2 August 2002, all blackfin reef sharks under observation, and possibly some of the other species, left their lagoon and ocean ranges and disappeared from human view, a unique evacuation for which no explanation was found. The event suggests an unknown pattern or influence at work which was perceived by sharks, but was not apparent to those investigating.