Female wanted for the world's rarest turtle: prioritizing areas where Rafetus swinhoei may persist in the wild

Abstract

The Yangtze giant softshell turtle Rafetus swinhoei is the rarest turtle species, with just two individuals known to be surviving, one male in a zoo in China and one individual recently identified as a female in the wild in Viet Nam. As the species is on the brink of extinction, it is an urgent priority to search for additional individuals in the wild, and for areas where it may still be present. Here, we analysed areas where the species may still occur, identified through interview surveys in Viet Nam. In addition, we introduced a novel system for evaluating the potential for occurrence of this rare and elusive freshwater turtle, using a conservation priority index. This index was based on three recorded variables: (1) probability of the species' presence based on interviews with local fishers, (2) degree of habitat alteration, and (3) fishing intensity, with the latter two based on experts’ evaluation of the sites where the species could potentially be present. There were at least 13 independent, reliable sightings in the 2010s, seven of which were in 2018–2019, indicating that R. swinhoei potentially persists in the wild. Although the species was confirmed at only one site, there are at least three more sites where it is likely to be present, and 13 sites of conservation interest. We provide a description of all sites where the species is potentially present, and a summary of relevant interviews. The Da River system has the highest number of recent sightings. We recommend that a research and conservation project be initiated urgently, and outline how such a project could be implemented.