Mopelia, also called Maupihaa situated 160 km southwest of Maupiti, is an atoll considered as almost a possession of Maupiti. Nearly circular, its diameter is 8 km and its surface about 4 km². The Passes of the atoll is difficult and is just large enough so that small ships can enter the lagoon. Wallis was the first European to see the island, after his stay in Tahiti in 1767. The atoll counts a population of about ten people whose main activity is the harvest of pearl oysters and copra. Oysters are brought to Maupiti then sold to the Tuamotu that send's them back by plane in their islands of origin after being implanted with a nucleus (a marble of mother of pearl). This isolated island also shelters numerous colonies of birds and turtles.