A snapshot of times long gone

The Chishui River, a tributary of the Yangtze River, is the last safe haven for a number of rare and endangered species of fish, so it should never be developed commercially, a senior hydrobiologist said.

Cao Wenxuan, an academician of the Chinese Academy of Sciences and senior researcher at the academy's Institute of Hydrobiology, said he understood the economic priorities of the local authorities, who are attempting to foster rapid growth, but stressed that the government should spare no efforts to preserve the waterway because it's the only stretch along the upper reaches of the Yangtze River that doesn't have a dam.

"That means the river is a living example of what the Yangtze River used to be before it was overexploited by humans," Cao said. "Moreover, keeping the river clean will allow endangered species in the Yangtze River to survive."