A dolphin frolics off the coast of Huoshaoyu Island in Xiamen, Fujian province. ZHOU QING/FOR CHINA DAILY

Auxiliary measures

Despite the challenges posed by the vastness of the sea and human's reliance on marine resources, efforts have been made to restore their habitats and population.

In response to the susceptibility of the Chinese white dolphin to underwater blasting, Xiamen has developed a process for reviewing and supervising underwater construction projects.

This includes establishing reference thresholds for the impact of underwater noise on the species, and determining the minimum safe distance for them during construction work.

Considering their sensitivity to sound, Xiamen employs an underwater "sound wall" before the construction to ward off Chinese white dolphins from the area.

In 2022, Xiamen introduced an advanced monitoring and control system, incorporating intelligent monitoring with early warning capabilities, real-time monitoring and online management for protection patrols. With 65 monitoring points and 73 cameras, the system covers a range of crucial activity zones for the Chinese white dolphin, and has effectively documented the behaviors of this rare species on multiple occasions.

To boost the supply of food and assist in population recovery, the city's bureau of natural resources and planning regularly organizes activities to release food resources for the Chinese white dolphin in the city's waters. A total of 250,000 fry were released in July last year.

With sustained government investment and a dedicated focus on ecological restoration, the population of Chinese white dolphins in the waters off the coast of Xiamen has remained stable, with a gradual increase in recent years.

"They've gone from around 60 in the early 1990s to 80 in 2020," said Xu, adding that the age structure of the population has improved, with half of them being young adults.

Li Hongyang contributed to this story.