The Yangtze finless porpoise, commonly known as the "River dolphin" or "River pig" by local people on account of its less-than-stunning looks, is a unique freshwater porpoise subspecies that has lived in the Yangtze River and nearby lakes for more than 25 million years. Now this much-adored mammal that has a smiley face and an intelligence level comparable with a gorilla risks soon going extinct.
Since early March, some 12 river dolphins, regarded as the giant panda of the water and classified as a second-level protected animal in China have been found dead, one after another around the Dongting Lake Basin area in Hunan Province, China.
Of the 12 dead river dolphins, three were highly decomposed and buried where they were found, and another two were washed away by the water. The other 7 bodies have been salvaged for post-mortem examination.
After three consecutive years of field investigations by the World Wildlife Fund (WWF) and the Institute of Hydrobiology of the Chinese Academy of Sciences, it has been found that there are all together only 1500 of the Yangtze finless porpoises remaining. They are mainly in the Yangtze River, with eighty-five living in Dongting Lake, and between three and four hundred in Poyang Lake. But they are diminishing at an annual rate of 5% to 10%. This vanishing animal is now even rarer than the panda.
According to the preliminary autopsy discovery of the mammal, "there were no fatal exterior wounds found, and there was no residue found in their digestive system. Besides, the animals seemed to have developed some lesions," Xie Yongjun, member of the Yueyang City Finless Porpoise Society as well as a senior veterinary surgeon pointed out. "They are either attacked by infectious disease, or are being poisoned or starved to death."
With the cause of death still inconclusive, some of the porpoises have been sent to the Wuhan Institute of hydrobiology for further analysis.
Wei Baoyu, the project leader of the WWF in Hunan Province summed up the main reasons endangering the river dolphins: ever scarcer food resources, water pollution as well as dredging destroying the riverbed where the river dolphins reproduce.
In addition, the increasingly busy lake transport of large barges is jeopardizing the lives of these porpoises which rely on sonar to navigate. Many river dolphins mistakenly take a motor's acoustic waves as those of their fellow dolphins, and get injured or killed by the propeller when they swim close. For example, the first two adult porpoises found dead last month were confirmed to have been hit by a vessel's propeller.
According to Dong Lijun, a researcher at the Wuhan Institute of hydrobiology, the river dolphins have a group habitat character. It's called the 1:4 theory, if one dies, another three of them are threatened. This implies that although there have only been twelve deaths of the animals up to now, those seriously threatened are actually far higher.
"The rapid declining population means that the remaining numbers are insufficient to maintain the continuation of their reproduction. This will inevitably lead to a total extinction," Dong explained.
In 2007, the Whitefin dolphin, another freshwater porpoise to be found only in Yangtze River was declared functionally extinct. It makes the finless porpoise, an even more ancient species than the former, to be left as the only mammal on the Yangtze River. This sad end to prehistoric species is just one more sign of the huge cost that China's rapid economic growth is making us pay.
Read the original article in Chinese
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