Abstract:

Background: Chondrichthyan fishes are among the oldest and most widely distributed vertebrate groups, playing a vital role in marine ecosystems. Although China provides critical habitats for chondrichthyan fishes, domestic research on this group has historically been limited. With the global decline of fishery resources, these species have attracted increasing international attention. Consequently, regional fisheries organizations and international conventions have imposed mandatory restrictions on the resource utilization and trade of sharks. Specifically, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) requires Contracting Parties to issue “Non-detriment Findings” (NDFs) for the international trade of Appendix II species and non-commercial trade of Appendix I species. As a key Contracting Party to CITES, China is still in the early stages of developing NDFs. For its future NDF development, it is essential to reference the diversity data and life history parameters of sharks from neighboring countries and regions. 

Methods: This study primarily relied on a comprehensive literature review to compile separate checklists of chondrichthyan species in the waters of Japan, Southeast Asia, Australia, and New Zealand. The Jaccard similarity coefficient was then employed to compare their species composition with that of chondrichthyan fishes in Chinese waters. Furthermore, relevant compliance techniques for chondrichthyan fishes listed in the CITES Appendices were discussed. 

Results: Japan, Southeast Asia, Australia, and New Zealand harbored 225, 284, 338, and 120 species of chondrichthyan fishes, respectively. The Jaccard similarity coefficients between these regions and China were 0.6080, 0.4519, 0.2195, and 0.1416, respectively. A review of the CITES Appendices and the submission status of NDFs revealed that, by March 2026, CITES had listed 216 species belonging to 35 genera, 14 families, and 5 orders, with 15 Contracting Parties having submitted 127 NDFs for 56 appendix-listed species. Given that China’s NDF development is in its infancy, this study selected the silky shark (Carcharhinus falciformis) to establish a six-step NDF framework for the introduction from the sea (IFS) of CITES Appendix II chondrichthyan species. Our preliminary assessment indicates that the overall risk level for the introduction of the silky shark from the sea is medium. This framework can provide methodological and data support for CITES authorities when formulating formal NDFs for specific silky shark cases, while also identifying the steps that require further data supplementation and expert consultation. 

Significance: This study further clarifies the diversity patterns of chondrichthyan fishes in China and its surrounding waters. It provides baseline information and technical support for China’s CITES compliance, offering a valuable reference for the conservation of chondrichthyan diversity and the sustainable utilization of resources in China and adjacent marine regions.

Key words: Chondrichthyan fishes, CITES, Jaccard similarity coefficient, NDF, silky shark