'Witness to Extinction' – The demise of the Yangtze Megafauna in China

A couple of years ago, the extinction of the Yangtze Dolphin became apparent after some exhaustive visual and hydrophone surveys throughout its known range.

Some 18 years ago, before I joined the World Bank, I worked as a consultant for the Chengdu Hydropower Design Institute in China to prepare the Environmental Impact Assessment for the massive Ertan dam, which was to be financed by what was then the largest-ever World Bank loan. Ertan is on the Yalong River in the headwaters of the mighty Yangtze, the third largest river in the world, and was to be the first of a ‘cascade’ of dams reaching up to the Yalong headwaters. Some of the biodiversity impacts related to migratory fish, but even back then it was clear that the Gezhouba Dam and then the Three Gorges Dam, which straddle the mainstem of the Yangtze, blocked the movements and thus breeding of all migratory species.

A couple of years ago, the apparent extinction of the Yangtze Dolphin or baiji hit the international news after some exhaustive visual and hydrophone surveys throughout its known range. The animal appeared in the news a few weeks later because another researcher had claimed to have taken a video of a baiji at long range – however the quality of the film made independent verification impossible, and there were even suggestions that what had been filmed was a floating plastic bag. Of course, extinction is a very hard thing to prove, and there may be one or even a few baiji left which have escaped detection. But the species, the only representative of an entire family, would appear to be at least ‘ecologically extinct’, playing no functional role in the Yangtze ecosystem. The lead author of the survey paper, Samuel Turvey, has written an honest eulogy to the species in Witness to Extinction – How we Failed to Save the Yangtze Dolphin. Ecological extinction now seems to be the most likely fate for other members of the Yangtze megafauna too.

I recall having a coffee at about that time with Lu Zhi, who is now both Professor of Conservation Biology and Executive Director of the Center for Nature and Society at Peking University and Director for Shan Shui Conservation Center, a newly established Chinese NGO. She remarked that while saddened by the news of the baiji, she was actually more struck by the relatively small amount of coverage the story generated in the Chinese media, and the general lack of concern even to the loss of a unique species, genus and family of mammal. What hope is there for any other threatened species?

The most recent bad news about the Yangtze megafauna is the claim that the peculiar and huge Yangtze Paddlefish, with an enormous ‘ proboscis’ has met the same fate. None has been seen in the wild since 2007 and no young fish has been seen since 1995. It seems as though this species is also ecologically extinct. How depressing it is that we will never again be awed by these harmless giants, which are said to have reached 7 meters in length and about half a ton in weight? Captive breeding is possible but finding suitable adults is a major challenge, and very little is known about keeping them in captivity.

The very large (2.5 m) Yangtze Sturgeon is also Critically Endangered. This fish suffered from illegal fishing and pollution but also from the Gezhouba and Three Gorges Dams. A reserve was declared below the Gezhouba Dam and in the following years a few sturgeon laid eggs there, but these have been steadily decreasing. There have been efforts to captive breed Yangtze Sturgeon – but there is something rather hollow in the celebrations of the recent release of 120,000 captive-bred, 16 cm long Yangtze sturgeons from the Chinese Sturgeon Research Institute financed by the Three Gorges Project Corporation. It’s not just that these are just the latest of the five million sturgeon released, but rather that they have become just a domesticated species, bred in captivity and then grown on in a modified waterscape. There are good economic reasons for doing all this because in Shanghai restaurants the meat can sell for about $1000 per kilo.

Two other large Yangtze species are on the brink of extinction – the Chinese Alligator and the Finless Porpoise. Although alligators are generally associated with the southeast USA, there is a second member of the genus which used to be widely distributed in China but which is now confined to just a few small fragmented ponds as a result of the relentless conversion of wetlands to agriculture. The poisoning of rats – a major food – has not helped either. The Chinese Alligator is perfectly able to breed and it can be found in its thousands in small and large zoos and research facilities, though some of these become destined for the restaurant trade. The most animals can be found at the Anhui Research Centre of Chinese Alligator Reproduction which has started to recreate wetlands for alligator reintroduction but, to be successful, farmers and developers need to accept the animals as part of the wetland landscape.

The Finless Porpoise in the Yangtze is in fact a sub-species of a species found in the seas of East Asia but it is the world’s only freshwater population of porpoises. Dr Zhao Xiujiang of the famous Institute of Hydrobiology in Wuhan and his colleagues completed comprehensive surveys of the remaining population in 2006. They concluded that there were about 1800 left, about half what was likely an underestimate made 15 years earlier. The Yangtze population is continuing to suffer from being trapped in fishing nets, dredging, water pollution and the confusion to their food-seeking sonar systems because of all the noise from the busy ship traffic along the river.

So, all in all a pretty depressing picture. There are of course many scientists in China who are concerned about the demise of these amazing animals, but there is certainly no national outrage that extinction point has been reached. It thus makes one rather despondent about the path of Chinese conservation.

Photo courtesy of kromatic under a Creative Commons license.