QINGDAO, May 21 (Xinhua) -- China on Monday began a survey of the number and distribution of the endangered finless porpoise in the Bohai and Yellow seas, in preparation for setting up a reserve in the area.

Chinese Academy of Fishery Sciences Yellow Sea fishery research institute will send a survey ship to the Yellow sea for 10 days on May 24.

The scientists will collect data on the porpoise population and distribution, as well as temperature, salinity, dissolved oxygen levels and pH value of the water.

The data will be used for the protection of finless porpoise in China's coastal areas, said the institution.

Finless porpoise, a dolphin-like mammal with aniconic "grin" on its face, has three subspecies in China's Yangtze River, Bohai and Yellow sea and South China Sea.

The population in the Yangtze is the most critical at around 1,000, due to pollution, over-fishing and river traffic. The population in the Bohai and Yellow seas has dropped to around 20 percent the level of 1980s.