Two Strategies for Researching the Endangered Yangtze Finless Porpoises Suggest Data-Poor Areas Are Worthy of Greater Conservation Efforts.

The distribution and abundance of species are crucial components of their population ecology and serve as the foundation for effective conservation efforts. However, baseline data may be insufficient in areas where surveys have been inadequately conducted, complicating the implementation of protective measures. In this study, we employed two complementary approaches to gather baseline information on the endangered Yangtze finless porpoise in the Jingjiang section of the Yangtze River. Firstly, we gathered information about porpoises from a questionnaire survey (fishers). The results indicate that porpoises have been encountered over the past few decades, suggesting that this area has always been the habitat of porpoises. Secondly, boat based visual line transect surveys were carried out from September 2021 to August 2024. These findings validated local fishers' ecological knowledge by demonstrating the presence of a substantive population inhabiting Jingjiang section. The abundance was estimated to approximately 39 individuals, which exceeds previous estimates. Additionally, we identify the core distribution area of finless porpoises in the Mucheng Park waters. Overall, this study has closed knowledge gap about porpoises in the region. The results provide a scientific foundation for the management and conservation of porpoises.