After years of overfishing and rampant dam-building, a senior fisheries expert with the Chinese Academy of Sciences has spoken out against the ecological threats facing the Yangtze River by calling for a 10-year fishing moratorium and joining environmentalists in decrying the proposed Xiaonanhai Dam.
In an article published in Oriental Outlook and translated by chinadialogue, Cao Wenxuan expounded on the importance of key Yangtze River fish species for the entire basin ecosystem and warned against what might happen if fisheries declined even further. His solution is a 10-year moratorium on fishing in the Yangtze so that fish numbers can recover. (This is not the first time scientists have called for a 10-year moratorium; just last year, two other fisheries experts made the same proposal.)
In the article, he and fellow fisheries expert Weng Lida, formerly head of the Yangtze Water Resources Protection Bureau (a body under both the Ministry of Water Resources and the Ministry of Environmental Protection) go on to warn against the Chongqing government’s plans for building Xiaonanhai Dam on the Upper Yangtze River and the impact that the Yangtze dam cascade, which includes Three Gorges Dam, has had on fish numbers. He also strengthened the position of environemntal activists by joining them in their critique of proposed fish passages and tunnels, which activists see as an ineffective solution to mitigating the negative impacts of the dam.
Dam cascade contributing to rapid decline
Cao and his colleagues are not alone in doubting the efficacy of fish passages. A recent publication by a host of fish migration professionals concludes from their global experience, “We have learned that it is always better to remove barriers because in this way we can revitalize our rivers. It is almost always cheaper than building a fish pass, and removal has multiple benefits for river naturalization – all aquatic and riparian flora and fauna will benefit! Such solutions can address a range of problems, of which fish migration may be just one” (Executive Summary, From Sea to Source).
[UPDATE: A new study published in Conservation Letters on Jan 16 reported that fish-passages built into dams on three major rivers in northeastern US have failed to allow migratory fish to pass through, raising questions for all the dams being proposed worldwide.]
Here is an excerpt from the article describing the severity of the decline in fish numbers as a result of dam construction on the Yangtze (emphasis added later):
Observations by the Chinese Academy of Sciences found that, before the dam at Gezhou was built, fish eggs and fry from spawning grounds upstream in Chongqing, Wanxian and Zigui would float down to the middle reaches of the river before hatching and growing. Gezhou is a “run-of-the-river” hydropower dam, and most of the eggs and fry which pass through the sluice-gates do survive. But bubbles of gas are found in the bodies of some of the fish, which do not survive.
And at the Three Gorges Dam, where in June 2003 the reservoir was filled to a depth of 139 metres, the majority of the fish passing through the sluices are believed to die as a result of nitrogen poisoning.
In 2007, the reservoir was filled to 156 metres, and 98% of the 316 million fry passing through the dam died. Many of the 912 million fry of the “four farmed fish” passing through in 2008 also died.
Cao explains that a dam changes the natural flow and rise and fall of the water, and this – especially the filling of a deep reservoir – affects the local climate and reduces the river’s ability to cleanse itself. Large quantities of harmful substances are produced, affecting the food chain.
“In the cold water of reservoirs like Anjiang and Danjiangkou, the methylation of heavy metals creates organic substances, which are absorbed by plankton and enter the human food chain and damage health,” says Cao.
“The water flow at Gezhou isn’t bad. The Three Gorges is a bit worse, and then Xiluodu and Baihetan are worse again. And it’s not just methylation. The vegetation at the bottom of the reservoir becomes methane, which is a greenhouse gas – that means carbon emissions.”
The implications of this final remark by Cao is also important given the debates that have raged on over Weibo (China’s Twitter) about whether hydropower can be considered a clean and green source of renewable energy.
Xiaonanhai “in breach of regulations”
The reserve boundaries were redrawn twice from 2005 to 2011 to make way for hydropower development. “It’s as if national nature reserves are optional,” says Cao. “It’s unacceptable. It doesn’t matter if you’re talking about fish or about people – you’ve got to obey the law.”Cao also went on to explain why environmental groups and experts oppose the Xiaonanhai Dam on the Upper Yangtze, which has been avidly promoted by the Chongqing government, despite the location of the dam and its reservoir in the Upper Yangtze Rare and Endemic Fish National Nature Reserve. According to China’s Nature Reserve Regulations, no “production facilities” can be built within the core or buffer zone of a nature reserve, while in the surrounding area, no production facilities are allowed which pollute, damage resources or spoil the appearance of the reserve. “So building this dam, which obviously affects the aquatic ecology, is in breach of this regulation,” says Cao.
In addition, preliminary construction at the dam site began as early as March 29, 2012 despite the lack of an approved Environmental Impact Assessment (EIA) and wide-spread criticism from experts and the general public. The resettlement process has also begun for the 200,000 people that would be affected, and there are already reports of unfair compensation and lack of prior and informed consultation.
While the project remains on hold, a coalition of environmentalists and activists has called on the public via Weibo to fight the project through the EIA process. They are also calling on the Chongqing government to respect the 18th Party Congress’ commitment to an “ecological civilization,” where economic growth should not be pursued at the expense of biodiversity and livelihoods. It remains to be seen whether the Chongqing government will commit to environmental protection, or whether it will opt for pursuing energy projects that promote polluting growth targets.