BEIJING – A survey of endangered porpoises in China’s longest river has yielded fewer sightings as intense ship traffic threatens their existence, scientists reported.
Chinese researchers spent 44 days tracking the finless porpoise — or “river pig” in Chinese — along a little more than half of the 6,000-km Yangtze River. The finless porpoise, which has only a small dorsal ridge instead of a fin, has been hurt by human intrusion and environmental degradation, global conservation group World Wide Fund for Nature, which supported the survey, said last month as the research began.
The WWF has warned the species, found only in China, could become extinct in 15 years if no action is taken.
The survey, which started Nov. 11, marked the most comprehensive study of the species since 2006. A similar expedition that year discovered just 1,800 of the porpoises.
Based on sonar tracking results, the scientists said a total of 91 finless porpoises were detected while traveling 3,400 km from the cities of Yichang to Shanghai, down sharply from 177 in 2006. But they said that was only an initial estimate, and warned further data and analysis are needed. They expect to have a final result within two months.
“There are fewer and fewer finless porpoises in the mainstream of the Yangtze River, while the animals were concentrating in the harbor areas in groups of three to five,” said a release issued by the scientists from the Yangtze River city of Wuhan.
“Our initial analysis concluded that this may be because there are comparatively more food resources in the harbor areas,” said Wang Kexiong of the Chinese Academy of Sciences, who served as deputy director general for the survey. “However, in the mainstream of the Yangtze River, especially in the harbor areas, traffic is very intense, which is a huge threat to the survival of finless porpoises.”
The 2006 expedition declared another species, a freshwater dolphin called the “Baiji,” extinct.
Zhang Xinqiao, a survey team member and WWF official, said, “Such intense ship traffic is a potentially deadly threat to finless porpoises, who totally depend on their sonar system to survive.”
Finless porpoise deaths have been caused by boat strikes and fishing gear accidents, as well as degradation of rivers and dolphin food sources, due to pollution and severe droughts blamed on climate change. China’s waterways have become heavily contaminated with toxic waste from factories and farms.