In the first of a new series of regular columns from China’s top environmental writers, Wang Yongchen investigates the Yangtze River dolphin, which a recent survey declared functionally extinct.
The baiji, one of the world’s four species of freshwater dolphins, left the oceans 20 million years ago and settled in the middle and lower reaches of China’s Yangtze River. The baiji has existed for around 25 million years, far longer than the famed giant panda, which has been around for five or six million years. The species is also described in the Erya, a Chinese dictionary dating back to 200 B.C., where it is named the “Goddess of the Yangtze”.
But how is this goddess faring in today’s Yangtze?
The Yangtze Freshwater Dolphin Expedition 2006, made up of experts from China, Japan, Switzerland, Germany, the UK and the US, conducted a six-week survey of the Yangtze River. The survey used the most advanced detection techniques to cover the 1,700 kilometres of the middle and lower reaches of the Yangtze – from Yichang to Shanghai – but they failed to find even a single baiji.
Scientists believe that when the Erya was written, the Yangtze was home to over 5,000 baiji. But by the 1980s, Chinese experts announced that this number had fallen to less than 300 and the World Conservation Union named the baiji as one of the world’s 12 most endangered species. In 1993, it was announced that the number of surviving baiji was less than 100; China’s Ministry of Agriculture found 13 baiji in 1997, and only four in 1998 and 1999.
“At the start we would try to encourage everyone, saying there were promising stretches of the river we hadn’t checked yet,” says Wang Kexiong, a member of the 2006 expedition from the Institute of Hydrobiology at the Chinese Academy of Sciences. “Then we would say – let’s go over those stretches one more time.” But after a week of going back and forth, his hopes had faded. “We still didn’t find any,” says Wang.
But what about other species of river dolphin? Today there are over 10,000 botos, or Amazon River dolphins, while dolphins in the Ganges and Mekong rivers each have growing populations of over 2,000. But the baiji may now be the first cetacean mammal that humans have driven to extinction.
Some say that the baiji was too old, that like the dinosaurs it was bound to die out sooner or later. But Zhou Kaiya, a professor of zoology at Nanjing Normal University, disagrees. The age of the species is irrelevant, says Zhou, human interference is the real problem. According to incomplete statistics, human activity was to blame for 90% of baiji deaths before 1985, in cases where the cause could be ascertained.
The 2006 expedition also investigated water quality in the Yangtze River. The results astounded Robert L. Pitman, a dolphin expert from the US NOAA Fisheries Ecosystem Studies Program, who described the water as “completely unsuitable for cetaceans.” Two scientists from the Swiss Federal Institute of Aquatic Science and Technology also collected water and silt samples. The results of their tests are still forthcoming, but a member of the survey said in a media interview: “There is already no plankton to speak of in the Yangtze. We used a specialised plankton net to trawl the river for 10 hours and only caught two shrimp, which were less than one centimetre long. It's hard to imagine that fish could survive here, and with no fish the baiji will starve.”
The baiji first caught the attention of China’s environmental NGOs and media organisations in 1997. Reports came in of a dead baiji found with 103 separate open wounds; baiji with crushed skulls and dolphins sliced in two; and a pod of four baiji – two of them pregnant females – killed by explosions used to clear waterways in central China’s Hubei province. What stunned another expedition member, Yao Zhiping, was the amount of shipping on the river. On south China’s Poyang Lakealone, she counted 1,200 sand dredgers before giving up. Industrial growth on the banks of the Yangtze River and the increased use of fertilisers are both damaging water quality. One report found much higher levels of pollutants in the bodies of the baiji than in those of sea dolphins. The Yangtze River seems to have lost its capacity for natural purification.
As Liu Jiankang and Chen Yiyu, from the Chinese Academy of Sciences, write in their Suggestions for Protecting the Baiji: “Human activity on the Yangtze, including fishing, shipping and irrigation are increasing – and so is pollution. These are the main reasons for the shrinking baiji population.”
Before the expedition, the scientists had estimated that less than 50 baiji survived; and when a population is that small, zoologists agree that the chances of saving it are slim. The accepted best practice for preserving endangered species is to relocate them to a safe area. If the survey had found any baiji, it would have used details from the survey to capture and relocate them next spring, moving them to a protection zone in Hubei Province’s Tian'e Zhou: a lake and reserve that used to be part of the Yangtze River. But none were found.
The search has now ended, but could there be any baiji left? Nobody can say for sure; yet Wang Ding and his colleagues at the Institute of Hydrobiology believe the endearing animal still survives.
And if this is the case, could cloning and in vitro fertilisation help save it? The baiji and the sea-dwelling Chinese white dolphin are closely related; could they be interbred? Wang Ding says the chances of mating the baiji with the Chinese white dolphin are small, since they belong to different families. Cloning could be a possibility, but an extremely difficult one that would require cells to be transplanted into another animal in order to grow, and there are no animals in China closely related enough to make this a realistic option.
The Chinese people gave the baiji the name “Goddess of the Yangtze”. But if our dreams of seeing the goddess again are to come true, our slogans about “living in harmony with nature” need to become more than just words.
Yongcheng Wang is a reporter for China National Radio. In 1996, she founded Green Earth Volunteers, which campaigns environmental protection issues in China. Wang is also a winner of the Globe Award, China's top environmental prize.