SNP-based species identification of sympatric Carcharhinus galapagensis and C. obscurus sharks to support conservation monitoring in oceanic habitats

Abstract Carcharhinus galapagensis and Carcharhinus obscurus are challenging species to distinguish based on their physical characteristics, particularly after processing, which can hinder species-level monitoring in fisheries and conservation programs. In this study, we utilized diagnostic single nucleotide polymorphisms (SNPs) to identify 17 shark specimens collected from the Saint Peter and Saint Paul Archipelago in Brazil, a remote marine protected area in the equatorial Atlantic. Our analysis confirmed the presence of both species: nine individuals were identified as C. galapagensis , seven as C. obscurus , and one was classified as a putative hybrid. We also developed a cost-effective, high-throughput SNP-based method for accurate species identification. This new tool enhances the precision of species identification in both fisheries-dependent and independent data, facilitating better management and conservation efforts for these ecologically important sharks.