Sampling
Eight specimens of tiger shark (G. cuvier ), 13 black tip shark (C. limbatus ), and 12 grey reef shark (C. amblyrhynchos ) were collected off New Caledonia. Total genomic DNA was extracted from muscle tissue or fin clips, and preserved in 96% ethanol using QIAGEN DNeasy Blood and Tissue purification kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocols. Double-digest restriction-associated DNA (ddRAD) libraries were prepared following Peterson et al. (2012) using EcoRI and MspI restriction enzymes and a 400-bp size selection. The genomic libraries obtained were sequenced with a HiSeq 2500 Illumina sequencer (single-end, 125 bp). Exon capture data of eight black tip reef shark (Carcharhnius melanopterus ) from New Caledonia (Maisano Delser et al. 2019) were included in this study for comparative purposes.