Data from: Direct genetic evidence for reproductive philopatry and associated fine-scale migrations in female blacktip reef sharks (Carcharhinus melanopterus) in French Polynesia.

Conservation of top predators has been emphasised as essential in an ecosystem due to their role in trophic chain regulation. Optimization of conservation strategies for these endangered marine top predators requires direct estimates of breeding patterns and connectivity, which are essential to understand their population dynamics. While there have been some attempts to investigate breeding patterns of reef sharks from litter reconstruction using molecular analyses, direct fine-scale migrations of female sharks for parturition as well as connectivity at a medium scale, such as between islands, remain mostly unknown. We used microsatellite DNA markers and a likelihood-based parentage analysis to determine breeding patterns of female blacktip reef sharks in Moorea (Society Islands, French Polynesia). Such an approach demonstrates that while most females gave birth at their home island, some migrated to specific nursery areas outside their home range, sometimes going to another island (up to 50 km across deep ocean). Analysis also revealed that females migrated to the same nursery on every birthing event. Many offspring showed a high level of inbreeding indicating an overall reduced population size, restricted movements and dispersal, or specific mating behaviour. Females represent the vectors that transport the genes at nursery grounds, and their fidelity should thus define reproductive units. As females seem to be philopatric, males could be the ones dispersing genes between metapopulations. These results highlight the need for conservation of coastal zones where female reef sharks seems to exhibit philopatry during the breeding season