Critically endangered porpoises successfully released back into the wild

Bob Yirka
news contributor

Lisa Lock
scientific editor

Robert Egan
associate editor

A team of conservation and wildlife specialists affiliated with several institutions in China has successfully released two Yangtze finless porpoises back into the wild after moving them to a protected area for two years. As in the journal Biology Letters, the group cared for the porpoises in their protected area and then followed them after their release back into the wild.
The Yangtze finless porpoise has been identified as a critically endangered freshwater cetacean. It is the only known freshwater porpoise that lives only in China's Yangtze River system. Its population level has dropped dramatically over the past several decades due to loss of habitat, overfishing and other human activities—it is believed that there are now just 595 of them left in the entire river system. The team has been attempting to increase the number of porpoises living in the river by caring for some of them in captivity and then releasing them back into the wild.
The researchers captured two male specimens that had ventured beyond their normal habitat, perhaps while looking for a more suitable place to live. Unfortunately, such places offer little in the way of food, which means, without intervention, the two males likely would have died. The research team took them to a protected part of the river, which meant that they would not be in danger of being caught in fishing nets or harmed by collisions with boats. Each was also given a medical exam and implanted with an ID chip.
The two porpoises were left to their own devices in their protected environment for two years, with the research team checking on them periodically to make sure they were doing okay. After two years, when the two males were deemed healthy enough to return to the wild, they were moved to a part of the river where groups of other porpoises were residing. The hope was that the two would be accepted by a pod because solo porpoises are not believed to fare well.
After release, the two males were monitored closely to ensure that they were able to move about safely and find enough food to eat. The researchers also watched for acceptance by other porpoises. After just three days, the researchers found that both males had been accepted into pods and appeared to be thriving. Subsequent monitoring showed both continuing to do well. The research team suggests that it is possible to help at-risk marine animals such as the Yangtze finless porpoise through relocation programs.
More information: Jiansong Qiu et al, Rebuilding the critically endangered Yangtze finless porpoise population: successful release from an ex situ conservation programme, Biology Letters (2025).
Journal information: Biology Letters
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