Healthy stocks in many reef fisheries have suffered overfishing, with bech-de-mere (sea cucumber), pearl oyster, dugong and turtle fisheries having collapsed in the 20th century.
Both cultured pearls and natural pearls can be obtained from pearl oysters, though other molluscs, such as the freshwater mussels, also yield pearls of commercial value.
Fishing restrictions and competition mean they can't rely on trading goods such as sea slugs and pearl oysters, which they used to collect while free-diving to depths of 25m.
