科技英语新闻：Yangtze River dolphin population to decrease by 80% in 30 years: experts

YUEYANG, Hunan, June 2 (Xinhua) -- The population of finless porpoises, an endangered species of freshwater dolphin that lives in China's Yangtze River, may decrease by over 80 percent over the next 30 years, experts said on Thursday after conducting a field survey along the river.

The rare species will edge closer to extinction if no action is taken, said Wang Ding, a dolphin expert from the Hydrobiology Institute of the Chinese Academy of Sciences.

Wang's team conducted a survey on Poyang Lake, Dongting Lake and other locations along the Yangtze from Sunday to Wednesday this week.

The dolphin population currently stands at 1,000, even lower than that of the giant panda, Wang said.

The dolphin population is decreasing by a rate of 6.4 percent annually, Wang said.

"The next ten years will be a critical period for the conservation of this species," Wang said.

A long-lasting drought in central China has lowered water levels in many of the region's lakes and rivers, doing great harm to the dolphins' habitat and leading to a decrease in population, Wang said.

Mei Zhigang, a member of Wang's survey team, said that human activity has also contributed to the dropping population.

Mei said that large numbers of shipping vessels on the Yangtze have impeded the dolphins' migration path, causing them to reproduce less frequently.