Chinese white dolphins swim beside a ship near Huoshaoyu Island. ZHOU QING/FOR CHINA DAILY

Breeding methods

Xu attributed the vulnerability of the Chinese white dolphin, nicknamed "the giant panda of the sea", partly to its demanding living habits. He said that the breeding and nurturing of this marine animal are even more challenging than that of the giant panda.

"When a panda is born, we can capture it and raise it through artificial breeding, but as for dolphin calves, it doesn't work. If a dolphin calf is taken out of the water, its skin cannot tolerate it, and then if you put it back in the water, it cannot breathe," Xu said.

As marine mammals, newborn dolphins are unable to eat fish or surface to breathe and have to rely on their mothers for the first three years to provide them with milk, constantly bring them to the surface for air, and teach them how to swim, said Liu Wei, deputy director of the nature reserve.

The mortality rate of newborn dolphins in the wild exceeds 50 percent, Liu said.

To better understand their reproduction and protect the rare species, in 2002 Xiamen invested more than 58 million yuan ($8 million) to build a targeted rescue and breeding base for the Chinese white dolphin.

Located on Huoshaoyu Island, the city's largest uninhabited island, the base was officially put into use in 2011 and consists of a rescue center, a breeding center and a Chinese white dolphin science museum.

Liu said natural breeding under artificial feeding conditions can optimize and increase the local population.

"Because of their extremely small population in Xiamen, recent experiments have indicated that Chinese white dolphins may suffer from genetic problems resulting from inbreeding. Under captive conditions, we are contemplating the introduction of some healthy Chinese white dolphins from regions with comparatively larger populations for breeding purposes," Liu said.

The reproductive process of the Chinese white dolphin closely resembles that of humans. They have a gestation period of 10 to 12 months and typically give birth to only one offspring at a time. When giving birth, it is crucial for the tails of the calves to come out first, otherwise they may suffocate and die, Xu said.

She added that the base is applying for funding to offer the dolphins a set of prenatal checkups akin to those provided for humans. Based on the changes in progesterone levels during pregnancy, the center can determine their pregnancy status and give them specialized prenatal care and birth services.

At present, four injured bottle-nose dolphins are recuperating at the base, along with four injured sea turtles. Up to now, the base has been involved in rescuing more than 20 rare marine animal species.