The Bull Shark (Carcharhinus leucas) faces varying levels of exploitation around the world due to its coastal distribution. Information regarding population connectivity is crucial to evaluate its conservation status and local fishing impacts. In this study, we sampled 922 putative Bull Sharks from 19 locations in the first global assessment of population structure of this cosmopolitan species. Using a recently developed DNA-capture approach (DArTcap), samples were genotyped for 3,400 nuclear markers. Additionally, full mitochondrial genomes of 384 Indo-Pacific samples were sequenced. Reproductive isolation was found between and across ocean basins (eastern Pacific, western Atlantic, eastern Atlantic, Indo-West Pacific) with distinct island populations in Japan and Fiji. Bull Sharks appear to maintain gene flow using shallow coastal waters as dispersal corridors, whereas large oceanic distances and historical land-bridges act as barriers. Females tend to return to the same area for reproduction, making them more susceptible to local threats and an important focus for management actions. Given these behaviours, the exploitation of Bull Sharks from insular populations, such as Japan and Fiji, may instigate local decline that cannot readily be replenished by immigration, which can in turn affect ecosystem dynamics and functions. These data also supported the development of a genetic panel to ascertain the population of origin, which will be useful in monitoring the trade of fisheries products and assessing population-level impacts of this harvest.

A total of 922 putative Bull Shark samples (muscle or fin clip) were collected between 1980 and 2019 from 19 different countries or water bodies (termed 'sampling locations') around the globe in all major ocean basin regions: the eastern Pacific (E-PAC), western Atlantic (W-ATL), eastern Atlantic (E-ATL), and the Indo-West Pacific. Initially, 188 samples with a minimum of 10 samples per location were genotyped following the DArTseq approach (according to Feutry et al., 2017). Overall, 1,014 sample libraries, including 92 technical replicates, were genotyped with the DArTcap protocol. The full mitochondrial genomes of 384 putative Bull Sharks from the E-ATL, IWP, and E-PAC were sequenced to investigate their matrilineal evolutionary history.

Raw data are provided in Excell .csv file. Quality-filtered SNP data are provied as .Rdata. All analyses were performed in R 4.0.2, mainly using the following packges: radiator, adegenet, stratag, diveRsity, and rubias.Funding provided by: Sea World Research and Rescue FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100009034Award Number: 27