Captured intentionally or as by-catch, manta ray populations have declined due to fisheries. Most direct fishing is for their gill rakers, which are used as medicine in Asia. Hong Kong is one of the major importers of manta ray gill rakers. Manta rays are also caught or killed accidentally by fishing gear or even by protective shark nets around beach waters. According to some researches, it is believed that the number of manta rays around the globe has declined by 30%.