Social Clustering and Conservation Implications for Critically Endangered Taiwanese Humpback Dolphins (Sousa chinensis taiwanensis)

Abstract

In social species, social relationships of an individual play a crucial role in its fitness, and the social structure of a population can be vital to its viability. This study investigated the social network of the critically endangered Taiwanese humpback dolphin (Sousa chinensis taiwanensis) population during the periods 2017–2020 and 2021–2023. We observed a reduction in the strength and reach of the social network compared with a decade ago. The population could be divided into three clusters, each characterized by distinct age compositions and network metrics, with limited intercluster associations and minimal overlap in core areas. The decline and ageing of the northern cluster suggested the need for further research into its habitat quality. In the central cluster, which previously had high calf sighting rates, low intracluster association and a limited number of young individuals raised concerns about reproductive constraints. The southern cluster, although most socially vigorous, partly occupied areas outside the protected zone. Our findings emphasized the need for cluster-specific management strategies to enhance conservation efforts.