WUHAN, Dec. 12 (Xinhua) -- Chinese scientists have found a sharply shrinking population of endangered finless porpoises in the country's longest river in an ongoing survey.
As of Wednesday, the scientific survey team has found about 856 finless porpoises in the middle and lower reaches of the Yangtze River, said Wang Ding, the team leader.
The team attributed the decrease mainly to the busy shipping traffic in the Yangtze.
It is the most comprehensive survey since 2006, when research found the population of finless porpoises stood at to 1,800 in the Yangtze and two lakes linked to the waterway.
On the Yichang-Wuhan river section in the middle reaches of the Yangtze, the team has found only 39 finless porpoises, a decrease of about two-thirds from the figure in 2006, said Wang Kexiong, deputy director with the team.
While researching Dongting Lake, the team found only about 150 finless porpoises, about a 40-percent decrease from the figure in 2006 in the same waters, he added.
As the species most strongly associated with the Yangtze, finless porpoises are the barometer of the river's ecological conditions.
The 40-day survey comes after more than 20 of the porpoises were found dead in the Yangtze River and two nearby lakes earlier this year.
The team set off on Nov. 11 from central China's city of Wuhan along the Yangtze River.x It consists of researchers from the Ministry of Agriculture, the Chinese Academy of Sciences and the World Wide Fund for Nature (WWF).
A 2010 WWF report blamed illegal fishing, inadequate water conservancy facilities and pollution in the Yangtze, China's busiest waterway, for the declining number of porpoises.