1. The tiger shark (Galeocerdo cuvier) is a common widespread coastal-pelagic shark species whose population genetic structure has only recently been the object of genetic studies.2. In this study, the tiger's shark mitochondrial DNA control region was sequenced for a sample of 172 individuals from the western Atlantic and from Australia's east coast in the Pacific Ocean.3. The results show a moderate variation in genetic diversity (h = 0.615 ± 0.038, π = 0.00184 ± 0.00021) with a strong population structure between Atlantic areas (Φ ST = 0.28141, P = 0.00001).4. The maternal lineage has high site fidelity, which paradoxically is coupled with connectivity across open ocean stretches to Fernando de Noronha Archipelago, which is identified as an important hotspot for this species. These results help with the understanding of what drives the displacement of this shark, at intra-and/or inter-ocean basins levels, and can help inform the implementation of future conservation and management measures.5. We recommend that the conservation of genetic diversity should be maintained at a global level and its maintenance should be pursued diligently in all populations of tiger shark. As the Fernando de Noronha region in the western Atlantic appears to contain the largest global genetic diversity of the species, this area should be treated as a marine reserve or ecological refuge for the tiger shark.

Information regarding population structure and genetic connectivity is an important contribution when establishing conservation strategies to manage threatened species. The oceanic whitetip shark, Carcharhinus longimanus, is a highly migratory, large-bodied, pelagic shark listed by the IUCN (International Union for Conservation of Nature) Red List as "vulnerable" throughout its range and “critically endangered” in the western north Atlantic. In 2014, the species was protected globally under Appendix II of CITES (Convention on International Trade in Endangered Species), limiting and regulating trade. This study used partial sequences of mitochondrial DNA (mtDNA) control region to determine the population genetic structure of oceanic whitetip sharks across the Atlantic and Indian Oceans. 724 base pairs were obtained from 215 individuals that identifed nine polymorphic sites and defined 12 distinct haplotypes. Total nucleotide diversity (π) was 0.0013 and haplotype diversity (h) was 0.5953. The Analysis of Molecular Variance (AMOVA) evidenced moderate levels of population structure (ɸST = 0.1039) with restricted gene flow between the western and eastern Atlantic Ocean, and a strong relationship between the latter region and the Indian Ocean. Even though the oceanic whitetip is a highly migratory animal the results presented here show that their genetic variability is slightly below average of other pelagic sharks. Additionally, this study recommends that at least two populations in the Atlantic Ocean should be considered distinct (eastern and western Atlantic) and conservation efforts should be focused in areas with the greatest genetic diversity by environmental managers.

The tiger shark (Galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and it is caught in numerous fisheries worldwide, mainly as bycatch. It is currently assessed as near threatened by the International Union for Conservation of Nature (IUCN) Red List. In this study, we identified nine microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western Atlantic. The genetic diversity of these loci were assessed and revealed a total of 48 alleles ranging from 3 to 7 alleles per locus (average of 5.3 alleles). Cross-species amplification was successful at most loci for other species such as Carcharhinus longimanus, C. acronotus and Alopias superciliosus. Given the potential applicability of genetic markers for biological conservation, these data may contribute to the population assessment of this and other species of sharks worldwide.

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The tiger shark (Galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and is caught in numerous fisheries worldwide, mainly as bycatch. It is currently assessed as near threatened by the International Union for Conservation of Nature (IUCN) Red List. In this study we identified 9 microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western Atlantic. The genetic diversity of these loci was assessed and revealed a total of 48 alleles ranging from 3 to 7 alleles per locus (average of 5.3 alleles). Cross-species amplification was assessed in three other species: Carcharhinus longimanus, C. acronotus and Alopias superciliosus. Given the potential applicability of genetic markers for biological conservation, these data may contribute to the population assessment of this and other species of sharks worldwide.

The tiger shark (Galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and is caught in numerous fisheries worldwide, mainly as bycatch. It is currently assessed as near threatened by the International Union for Conservation of Nature (IUCN) Red List. In this study we identified 9 microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western Atlantic. The genetic diversity of these loci was assessed and revealed a total of 48 alleles ranging from 3 to 7 alleles per locus (average of 5.3 alleles). Cross-species amplification was assessed in three other species: Carcharhinus longimanus, C. acronotus and Alopias superciliosus. Given the potential applicability of genetic markers for biological conservation, these data may contribute to the population assessment of this and other species of sharks worldwide.