The discoveries have raised concerns finless porpoises, which have lived in the Yangtze River and adjacent lakes for more than 20 million years, could become extinct within 15 years, scientists said.
"Apparently the prolonged drought and low water level due to climate change and increasing offshore human activities are reducing the living space for finless porpoises, accelerating its extinction," Wang Kexiong, an expert of the Institute of Hydrobiology under the Chinese Academy of Sciences, told China Daily.
Scientists estimate the number of Yangtze finless porpoises has decreased to around 1,000.
The porpoises may have died due to starvation, poisoning or infectious disease, Xie Yongjun, a professor of animal husbandry at Yueyang Vocational and Technical College, said.
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