Abstract
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 3400 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 behaviors, 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.
| Original language | English |
|---|---|
| Article number | e9837 |
| Pages (from-to) | 1-22 |
| Number of pages | 22 |
| Journal | Ecology and Evolution |
| Volume | 13 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 2023 |
Bibliographical note
Funding Information:This work was supported by the Sea World Research and Rescue Foundation Inc, the Ord River Research Offset grant through CSIRO, and the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government's National Environmental Science Program. FDD was supported by a joint UTAS/CSIRO scholarship and the Quantitative Marine Science program. Samples from Réunion Island were collected as part of projects EcoRecoRun and Eurraica funded by the DEAL/SEB. We would like to acknowledge Lei Yang, William White, Jennifer Ovenden, Jessica Morgan, Thomas Poirout, Arie de Jong, Jeffrey de Pauw, A. Bodycott, J. Young, D. Young, A. Murray, O. Masens, M. Miller, D. Johnson, Betty Laglbauer, Sierra Fisheries, Pelagios Kakunja, Blue Resources Trust, NSW DPI Fisheries Bull Shark research, Beqa Adventure Divers, the Operations staff of the KZN Sharks Board (SAF), and the many Traditional Owners, assistants, and volunteers for their help with obtaining samples. In respect to this, we also thank all fishers and landing sites workers for their help in providing access to the sampled specimens. We appreciate the work from Marc Dando for providing the Bull Shark illustration. FDD thanks Jessica Farley and Peter Grewe for the aid in importing the tissue samples.
Funding Information:
This work was supported by the Sea World Research and Rescue Foundation Inc, the Ord River Research Offset grant through CSIRO, and the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government's National Environmental Science Program. FDD was supported by a joint UTAS/CSIRO scholarship and the Quantitative Marine Science program. Samples from Réunion Island were collected as part of projects EcoRecoRun and Eurraica funded by the DEAL/SEB. We would like to acknowledge Lei Yang, William White, Jennifer Ovenden, Jessica Morgan, Thomas Poirout, Arie de Jong, Jeffrey de Pauw, A. Bodycott, J. Young, D. Young, A. Murray, O. Masens, M. Miller, D. Johnson, Betty Laglbauer, Sierra Fisheries, Pelagios Kakunja, Blue Resources Trust, NSW DPI Fisheries Bull Shark research, Beqa Adventure Divers, the Operations staff of the KZN Sharks Board (SAF), and the many Traditional Owners, assistants, and volunteers for their help with obtaining samples. In respect to this, we also thank all fishers and landing sites workers for their help in providing access to the sampled specimens. We appreciate the work from Marc Dando for providing the Bull Shark illustration. FDD thanks Jessica Farley and Peter Grewe for the aid in importing the tissue samples.
Publisher Copyright:
© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
