Validation of indicators for the welfare assessment of captive Yangtze finless porpoises ().

The Five Domains model (FDM) is a widely accepted framework for developing welfare assessment tools across various contexts, including wild animals under human care. However, only two protocols have been developed for captive cetaceans. This study aimed to create a welfare assessment protocol based on the FDM for captive Yangtze finless porpoises (YFPs; ). Indicators relevant to YFPs' welfare were selected via a literature review, and validated through two consecutive questionnaire surveys, four discussions with a panel of three experts, and a blind review conducted by three additional cetacean welfare experts. This process resulted in the validation of 46 welfare indicators, which were used to develop the Yangtze Finless Porpoise-Welfare Assessment Protocol (YFP-WAP) which, in its final version, contains 150 indicators. Moreover, intensity levels (the degree of impact of each indicator on the porpoises' welfare), valence (whether the indicator contributed positively or negatively to the porpoises' welfare state), and mental states associated with each indicator were also assigned by the panels of experts. Additionally, a confidence score was assigned to each indicator's intensity level, valence, and mental state that reflected experts' level of uncertainty regarding the indicator impact on the YFPs' welfare. This rigorous validation process provided transparency, helped ensure minimal bias, and reduced the likelihood of incorrect indicator elimination due to expert subjectivity. By integrating expert knowledge, the YFP-WAP provides a comprehensive approach to evaluating both positive and negative welfare states, supporting the ongoing care and management of YFPs in captivity.