Yangtze finless porpoise Photo: Courtesy of Jiang Meng, secretary-general of the Nanjing Yangtze Finless Porpoise Conservation Association

Yangtze finless porpoises, an iconic species in the country's longest river Yangtze, were observed in many sections of the river in East China's Jiangsu Province during the ongoing fourth comprehensive survey of the river. 

This indicates that the ecology of the Yangtze sections in the province has improved at a certain level in the past five years, the Global Times learned from researchers involved in the survey.

Organized by the Yangtze River Basin Fishery Administration under the Ministry of Agriculture and Rural Affairs, the expedition is being jointly undertaken by local fishery authorities of six provincial-level regions, scientific research institutions and social organizations.

The Yangtze finless porpoise, which is under top-level state protection, is an important indicator of the Yangtze River ecology. 

China conducted three comprehensive surveys in 2006, 2012 and 2017 in a bid to step up conservation efforts for the critically endangered species. According to the 2017 survey, there were 1,012 finless porpoises in the Yangtze River as well as Poyang and Dongting lakes, the Xinhua News Agency reported. 

According to Jiangsu local media, finless porpoise groups were observed in sections of the water in Nantong, Zhenjiang, Yangzhou and Nanjing on four consecutive days from Friday to Monday. 

Jiang Meng, secretary-general of the Nanjing Yangtze Finless Porpoise Conservation Association, who is also participating in the survey, told the Global Times on Monday that the conservation group had observed finless porpoises in many places during the expedition, increasing by a certain level compared with the previous survey in 2017.

Notably, the researchers observed mothers carrying four- to five-month-old babies in major water areas. This demonstrates that the ecology of the Yangtze River is comparatively conducive to the reproduction of the finless porpoise, according to Jiang.    

This year's survey was launched on September 19 with an aim to formulate a more targeted protection plan for the species, according to Xinhua.

It is also the first comprehensive survey conducted in the Yangtze River after a 10-year fishing moratorium in all-natural waterways along the Yangtze River and the Yangtze River Protection Law came into effect in 2021. 

More than 120 people and more than 20 fishery administration vessels have been sent for the scientific expedition, covering major habitats of the Yangtze finless porpoises, such as the trunk stream in the middle and lower reaches of the Yangtze River, as well as the Poyang and Dongting lakes, two tributaries of the Yangtze, according to Xinhua.

Data on the number and distribution of the species, as well as the environment of its habitats, will be collected during this scientific expedition to determine the factors that may threaten the species and evaluate the effect of current protection measures, according to Xinhua.

Environmental DNA technology is being used in this year's survey. The technology is an emerging species monitoring method. Through continuous sampling of the main stream of the Yangtze River, information on the types of aquatic organisms remaining in the water samples can be obtained, media reports said, citing researchers who are participating in the survey.

The expedition in Jiangsu Province wrapped up on Monday. Starting on Wednesday, expedition team from Jiangsu will launch a survey in the Hanjiang River jointly with a team from Shanghai.