GUANGZHOU, Oct. 27 (Xinhua) -- A video of dolphins playing in the wake of the waves near a man-made island, east of the Hong Kong-Zhuhai-Macao bridge, has caught the attention from netizens across China.

The 55-km Hong Kong-Zhuhai-Macao bridge that opened on Tuesday is the world's longest cross-sea bridge, connecting the mainland province of Guangdong with the country's two special administrative regions, Hong Kong and Macao.

During the nine-year bridge construction period, researchers have identified and registered a total of 2,367 dolphins, with no injuries of any dolphins reported.

"Though we cannot jump to the conclusion that the total number of white dolphins is increasing, most Chinese researchers would agree that the population number holds steady with only a few changing their activity zones," said Chen Tao, a researcher from the South China Sea Fishery Research Institute of Chinese Academy of Fishery Sciences.

Since 1997, Chen has been working to protect and monitor Chinese white dolphins. From 2013 to 2017, he and his colleagues spent about a week every month tracking the rare dolphins in waters covering over 5,000 square km.

With a slender body that is pink in its adulthood, the beloved dolphin is under first-class state protection.

The Pearl River Estuary, where the mega-bridge is situated, is among the nation's busiest vessel routes and also a major activity zone for Chinese white dolphins.

"Local authorities and workers have paid close attention to the environment preservation and marine resources conservation," said Yu Lie, deputy director of the bridge management bureau, adding that they have achieved "zero pollution" of the marine environment and "zero injury and death" of the dolphins.

According to local authorities, the Pearl River Estuary Chinese White Dolphin Reserve has supported more than 100 researchers in studying and protecting the mammal and trained over thousands of dolphin watchers.

Luo Guocai, 34, a certificated dolphin watcher, said his duty was to conduct a 10-minute observation of the sea each time before construction started.

The dolphins have to breathe every few minutes above the water, and in order to prevent potential harm, the watchers would knock on their boat a few times to scare them away.

The preservation efforts never stopped even after the construction was completed.

"Managerial personnel will continue to monitor the nearby environment and the dolphins via intelligent equipment including the bridge video surveillance system, the underwater tunnel's environmental monitoring as well as specially established research and observation stations on the man-made islands," said Yu.

Currently, Hong Kong, Macao, and Guangdong plan to establish a conservation alliance for the dolphins, involving non-governmental organizations in the routine rescue, information sharing, and scientific research, said Chen Hailiang, head of the administration of the reserve.

"We are constructing a bigger rescue and conservation base as well as increasing tissue samples and gene banks in a bid to better preserve the dolphins for generations to come," Chen said.