Researchers use binoculars to conduct monitoring work during a scientific expedition on Yangtze finless porpoises at the Shishou section of the Yangtze River, central China's Hubei Province, Sept. 23, 2022.Photo:Xinhua

Aerial photo taken on Sept. 24, 2022 shows a finless porpoises scientific expedition vessel at the Jianli section of the Yangtze River, central China's Hubei Province.Photo:Xinhua

Researchers use binoculars to conduct monitoring work during a scientific expedition on Yangtze finless porpoises at the Shishou section of the Yangtze River, central China's Hubei Province, Sept. 23, 2022.Photo:Xinhua

Researchers use binoculars to conduct monitoring work during a scientific expedition on Yangtze finless porpoises at the Shishou section of the Yangtze River, central China's Hubei Province, Sept. 23, 2022.Photo:Xinhua

A researcher uses a pair of binoculars to conduct monitoring work during a scientific expedition on Yangtze finless porpoises at the Shishou section of the Yangtze River, central China's Hubei Province, Sept. 23, 2022.Photo:Xinhua