HEALING THE ECOSYSTEM: Students release fish into the Yangtze River in Nanjing, Jiangsu Province, on June 6, 2010, as part of efforts to increase fish stocks in the river (SUN CAN)

Weng Lida, former Director of the Yangtze Water Resources Protection Bureau, said that the most polluted river in China today is the Yangtze. According to Weng, industrial discharges alone grew by 13 billion tons from 1990 to 2011.

The situation has worsened due to the construction of hydropower stations, which have cut off fish migration routes and destroyed their local habitats.

"With more hydropower projects being built along the Yangtze, the natural habitats of several species of fish have been gradually destroyed, leaving fewer places for them to reproduce," Zhao said.

Cao said that a dam changes the natural tides as well as the flow of a river, and this—especially the creation of deep reservoirs—affects the local climate and reduces the river's ability to cleanse itself due to the water becoming stagnant. Large quantities of harmful substances are produced, affecting the food chain.

According to the report by the Yangtze River Fishery Resources Committee and the WWF, there are plans to build 25 dams on the Jinsha River, one of the major sources of the Yangtze.

They will be built 100 km apart along the 2,308 km length of the Jinsha, according to the country's energy development plan. Once completed, the plants will have a generating capacity equivalent to four times the output of the Three Gorges Dam, the world's largest hydropower project with a generating capacity of 22.5 million kw.

According to the report, this will make the Jinsha a series of reservoirs and disrupt the flow of sediment through the Yangtze.

"It will cut the river into sections, completely changing the river's ecosystem, and it will have a devastating effect on the species living there and the water quality," Zhao said.

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

The environmental impact assessment for the Shuangjiangkou hydropower project, for instance, was filed two years after construction started in 2011.

Time to recuperate

Chen Jiakuan, a professor at the Shanghai-based Fudan University and a participant in the June expedition on the Yangtze, said that 450 million tons of sand flowed downstream through the river in the 1950s, compared to only 150 million tons today.

"The sand is creating excessive amounts of silt in the reservoirs, leading to a severe degradation in water quality which in turn changes the environment and has an effect on the fish in the river," Chen said.

However, the planned power plants along the Yangtze play a significant part in China's efforts to tap into the river's potential hydropower. "We don't have too many options. Perhaps the only thing we can do is to suggest a 10-year fishing ban," Chen said.

Cao first proposed the idea of a total ban on fishing lasting 10 years in 2006. He stressed that a whole decade is necessary to ensure the recovery of endangered fish and the Yangtze's ecosystem.

Before that, the State Council had imposed an annual ban on fishing starting in 2003 which lasts from April to June in 11 provinces through which the Yangtze flows.

Zhao complained that although fish populations increase during the ban period, heavy fishing afterward negates any real recovery.

Xie Songguang, an expert on saury with the CAS, agreed. He said that the current annual three-month ban allows fish to spawn, but it is far from enough to protect young fish. Most of the fish caught are in fact the baby fish, which have little economic value, but greatly affect the future fish population.

Wang Zhaomin, Director of the Hubei Provincial Fishery Bureau, also echoed the Cao and Xie's sentiments. A 10-year ban is plausible, since the annual consumption of freshwater fish is 3.53 million tons in China, while the amount of fish caught in the Yangtze is only 100,000 tons, less than 4 percent of the total consumption. Thus, it will not greatly affect the overall supply, Wang concluded.

In response, the Ministry of Agriculture agreed that "the ecosystem in the Yangtze is disintegrating," and said that it is developing a compensation plan for fishers working along the river.

Zhao believes that properly caring for the 140,000 fishermen in the 11 provinces affected by the total ban is crucial to the success of the plan. He called for the establishment of an agency to help coordinate the different interest groups in order to solve the problem.

Ren Wenwei, Director of the Shanghai Conservation Program of the WWF, along with several other scientists, has also proposed drafting a Yangtze River Basin Management Act and establishing a coordinating department directly under the State Council.

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