JINAN -- The Chinese Academy of Sciences (CAS) Monday launched a marine survey, with four vessels setting sail from three Chinese ports to research the health of China's coastal waters.

The "healthy ocean" joint voyage is commissioned to collect data in the Bohai Sea, the Yellow Sea and estuaries of the Yangtze River and Pearl River to facilitate future research, according to the CAS.

Two of the four research vessels departed from Qingdao, East China's Shandong province. The other two vessels departed from Yantai, also in Shandong, and Guangzhou, South China's Guangdong province, respectively.

The 10-day multi-discipline survey is expected to provide an in-depth understanding of the physical, geological and ecological changes in China's coastal waters.

Wang Fan, head of the CAS Institute of Oceanology, said the survey will be used to initiate long-term marine observation and research including on ecological restoration and disaster prevention and control.

The survey also came amid the pressing need for ecological research on the Pearl River estuary, which will face mounting environmental challenges with the construction of the Guangdong-Hong Kong-Macao Greater Bay Area continuing to advance, said Sun Longtao with the CAS South China Sea Institute of Oceanology.