China Focus: Survey renews extinction concerns of Yangtze porpoises
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E-mail Xinhua, December 25, 2012
Fewer finless porpoises have been spotted in China's Yangtze River renewing concerns that human activity is pushing the rare freshwater mammal to the verge of extinction, according to a scientific survey.
During the 44-day survey, researchers found 380 finless porpoises, or "river pigs" in Chinese, as they sailed between the cities of Yichang and Shanghai along a 1,200-kilometer section of the Yangtze River, the country's longest waterway.
With 540 porpoises tracked in Poyang and Dongting, two lakes that link to the river, in preliminary surveys in October, scientists estimated the number of the species to be fewer than 1,000. This indicates a sharp decline.
"The initial results have confirmed our worries that the porpoises are facing extinction," Wang Kexiong from the Institute of Hydrobiology, Chinese Academy of Sciences (CAS), told Xinhua.
Wang, who is also deputy director of the survey team, said the species, which is native to China, could die out in ten to 15 years if the trend is not reversed.
The survey, which was launched on Nov. 11, is most comprehensive on the species since 2006, when research found the population of finless porpoises down to 1,800 from the 3,000 at the turn of the 21st century.
The 2006 survey also pronounced the white-flag dolphin, a larger mammal found only in the river, close to extinction. Both mammals have been regarded as the symbol of the waterway and worshiped as river gods by local fishermen.
Apart from fewer sightings, the 2012 expedition also found the porpoises' habitats being isolated and concentrated in the river's harbour areas, probably due to more food resources there and disruption of their seasonal migration by the waterway's busy ship traffic.
Scientists have warned that intense water traffic along the Yangtze River, China's busiest waterway, has posed a huge threat to the river's endemic mammals.
"Navigation has become the main cause of death for finless porpoises," said Wang Ding, general director of the survey team. He said many porpoises had died in boat collisions in recent years after their sonar system was confused by the noise of ship propellers.
Wang also blamed water pollution and illegal fishing in the river for resulting in a lack of food for the porpoises.
A video released by the survey team showed the bank of one section of the Yangtze River was dotted with sand dredging machines and heavy-polluting factories making paper, steel and ships.
Statistics from the Yangtze River Water Conservancy Committee showed more than 32 billion tonnes of effluent pours into the river every year.
The latest survey was organized by the Ministry of Agriculture, the CAS and the World Wide Fund for Nature (WWF).
Wang Kexiong said the calculation of porpoise numbers required further analysis, and the final results would be published in two months.
Wang said before the launch of the survey that he hoped the results would prompt more public attention and government effort to protect the endangered mammal, including moving it onto China's top list of wildlife protection.
Authorities have planned the construction of more conservancy sites for finless porpoises, and a new artificial reproduction center will be built in three to five years. Endi
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