Fish ecosystem on Yangtze 'on verge of collapse'

Landscape changes since 2005 along the banks of the Chishui River, a tributary of the Yangtze River, suggest the grave effects of human activity on the ecosystem of China’s longest river. [PHOTO BY WANG LEI / FOR CHINA DAILY]

Human activity along the upper reaches of the Yangtze River - such as building hydropower stations and excessive fishing - has pushed its aquatic ecosystem to the verge of collapse, a report released on Thursday warns.

Researchers suggested starting a fishing ban along the entire river and enacting a national law to protect the "mother river" of China, as its fishery resources are experiencing a severe recession.

The number of fish in four major species has shrunk from more than 30 billion in the 1950s to less than 100 million, and the number of breeds has been reduced from 143 to 17, according to the report released by the Yangtze River Fishery Resources Committee under the Ministry of Agriculture and the World Wide Fund for Nature.

The report is based on a 12-day scientific expedition in five provincial-level regions in June, in which 32 researchers from government agencies and NGOs participated.

It was the first expedition of its kind to study the upper reaches of the Yangtze River regarding wetlands, aquatic diversity and water environment, according to the WWF.

Besides the sharp decrease in the number of fish, some species, such as the finless porpoise, have already become extinct, said Zhao Yimin, head of the Yangtze River Fishery Resources Committee.

The plight along the river is not catching much public attention "as people can buy fresh fish from a wet market every day. They don't realize how serious the situation is", Zhao said.

"The source species are reducing, leading to unsustainable development of aquaculture and an increasingly fragile ecosystem."

Zhao said China's fishery resources will be drained soon if no immediate action is taken.

The report cited over-exploitation of hydropower and lax law enforcement as major reasons behind the dire situation.

On the Jinsha River, 25 hydropower plants are being, or will be built 100 km apart along the 2,308 km tributary of the Yangtze, according to the country's energy development plan.

Once completed, the plants will have power-generating capacity equivalent to four Three Gorges Dam projects.

"It will cut the river into sections, and completely change the aquatic environment, bringing a devastating impact to species and water quality," Zhao said.

According to environmental laws, a power plant has to pass an environmental impact assessment before construction starts. However, a majority of the projects go ahead without any assessment, Zhao said.