Spread over 4.8 million square kilometres, the French Polynesian Marine Mammal Sanctuary is the habitat of more than twenty species of cetaceans. The « Groupe d’Étude des Mammifères Marins — G.E.M.M. » (Marine Mammal Study Group) is a non-profit organization founded in 2009 and dedicated to the conservation of whales and dolphins within the Sanctuary. The G.E.M.M. has been conducting research on bottlenose dolphins, humpback whales as well as other cetacean species in the Society and Tuamotu archipelagoes for more than 5 years. Our work mainly focus on tourism impact on cetacean populations as well as on ever-growing conflicts between marine mammals and fishermen around the islands of Tahiti and Moorea.