Comparative population genomics confirms little population structure in two commercially targeted carcharhinid sharks

Authors

Claudia Junge, The University of Adelaide, South Australia, Australia
Stephen C. Donnellan, The University of Adelaide, South Australia, Australia
Charlie Huveneers, Flinders University, Adelaide, South Australia
Corey J. A. Bradshaw, Flinders University, Adelaide, South Australia
Alexis Simon, The University of Adelaide, South Australia, Australia
Michael Drew, Flinders University, Adelaide, South Australia
Clinton Duffy, Aquatic and Reporting Unit, Department of Conservation, Auckland, New Zealand
Grant Johnson, Department of Primary Industry and Fisheries, Aquatic Resource Research Unit, Darwin, Northern Territory, Australia
Geremy Cliff, University of KwaZulu-Natal, Durban, South Africa
Matias Braccini, Department of Fisheries, Western AustraliaFollow
Scott C. Cutmore, The University of Queensland, Australia
Paul Butcher, Department of Primary Industries, DPI Fisheries, Coffs Harbour, New South Wales, Australia
Rory McAuley, Department of Fisheries, Western AustraliaFollow
Victor Peddemors, New South Wales Department of Primary Industries, Australia
Paul Rogers, South Australian Research and Development Institute, Adelaide, South Australia Australia
Bronwyn M. Gillanders, The University of Adelaide, South Australia, Australia

Document Type

Article

Publication Date

1-9-2019

Journal Title

Marine Biology

ISSN

Print: 0025-3162 Electronic: 1432-1793

Keywords

Populaton genomics, Carcharhinid sharks, Population structure, Cross-jurisdictional fishery assessments, Australia, Indonesia, New Zealand, Dispersal distances, Indian Ocean

Disciplines

Aquaculture and Fisheries | Behavior and Ethology | Genetics | Genomics | Marine Biology | Natural Resource Economics | Natural Resources and Conservation | Natural Resources Management and Policy | Population Biology | Spatial Science | Survival Analysis | Sustainability

Abstract

Many shark species are at risk of overexploitation due to their high economic value, slow maturation, and low recruitment compared to most teleosts. However, there is insufficient knowledge about population structure at different spatial scales necessary to optimise fisheries models. We used single-nucleotide polymorphisms (SNPs) obtained through complexity-reduction genome sequencing to quantify the population structure of two highly mobile and commercially fished shark species: bronze whalers (Carcharhinus brachyurus) and dusky sharks (C. obscurus). We applied a comprehensive approach to test several population-structure hypotheses and signal consistency across methods and marker type. We found that C. obscurus was panmictic across Australia and Indonesia and across the Indian Ocean to South Africa based on neutral loci, whereas for C. brachyurus, the westernmost Australian samples appeared to be separate from the rest. The southernmost east Australian samples indicated some difference from the rest of Australia and New Zealand based on candidate loci for C. brachyurus, and potentially also C. obscurus; however, the lack of a reference genome makes the interpretation difficult. Despite similar patterns in both species, subtle and potentially important structure differences emphasise the importance of studying each target species independently rather than assuming similar patterns from closely related species with similar dispersal abilities, as well as considering different marker types in future studies. We found evidence of connectivity across the regions sampled, suggesting that the cumulative effects of regional fisheries and the potential for cross-jurisdictional fishery assessments and management should be considered for Australian, Indonesian, and New Zealand populations.

Recommended Citation

Junge, C., Donnellan, S.C., Huveneers, C. et al. Comparative population genomics confirms little population structure in two commercially targeted carcharhinid sharks. Mar Biol 166, 16 (2019). https://doi.org/10.1007/s00227-018-3454-4