Chinese white dolphins, members of a species threatened by overfishing, water pollution and heavy marine traffic, were seen cruising off the coast of Jiangmen, Guangdong province, recently.

More than 300 of the dolphins have been registered in waters off Jiangmen in recent years, about 5 percent of the global population of the species, according to the city's bureau of natural resources. They span six age brackets, from baby to elderly.

Jiangmen has 4,880 square kilometers of sea and 352 islands. Since 2010, the city has reworked 134.22 kilometers of its coastline and invested in artificial reefs to provide food for the dolphins.

Conservationists, such as the WWF, are worried that a decrease in young white dolphins sighted in recent years could signal trouble for the population of the species (Sousa chinensis).