Relocating the animals to safer waters or putting them in artificial breeding programs are alternative protection methods, said Zhang Xinqiao, a World Wildlife Fund (WWF) expert who is also part of the survey team.

The survey was launched from the central China city of Wuhan along the Yangtze River on Nov. 11 amid worries that the finless porpoise may be on the verge of extinction.

Consisting of researchers from the Ministry of Agriculture, the CAS and the WWF, the 40-day survey was the most comprehensive of its kind since 2006, when a survey found that the number of finless porpoises had fallen to 1,800 and pronounced the white-flag dolphin, a larger mammal also native to the river, close to extinction.

China's finless porpoise population has dropped significantly in the past few years. [File photo]