HAIKOU — In the waters of a southern Chinese island, scores of palm-sized pearl oysters hang tidily on the breeding cages.

These oysters, scientifically known as Pinctada maxima, are primarily found in tropical and subtropical waters. In China, their wild populations are under second-class national protection.

Playing a role in filtering organic matter from seawater, these oysters require pristine water quality, minimal waves and an abundance of plankton for nourishment.

Pinctada maxima produces exquisite white pearls, renowned not only for their satin-like luster, but also for their silvery brilliance.