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Like a rolling stone: colonization and migration dynamics of the grey reef shark (Carcharhinus amblyrhynchos)
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  • Pierre Lesturgie,
  • Camrin Braun,
  • Eric Clua,
  • Johann Mourier,
  • Simon Thorrold,
  • Thomas Vignaud,
  • Serge Planes,
  • Stefano Mona
Pierre Lesturgie
Institut de Systématique Evolution Biodiversité

Corresponding Author:pierrelesturgie@outlook.fr

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Camrin Braun
Woods Hole Oceanographic Institution
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Eric Clua
EPHE PSL
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Johann Mourier
Université de Corse Pasquale Paoli
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Simon Thorrold
Woods Hole Oceanographic Institution
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Thomas Vignaud
CRIOBE
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Serge Planes
EPHE PSL
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Stefano Mona
Institut de Systématique Evolution Biodiversité
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Abstract

Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here we investigated the evolutionary history of the endangered grey reef shark (Carcharhinus amblyrhynchos) across its range by sequencing thousands of RAD-seq loci in 173 individuals in the Indo-Pacific (IP) . We first bring evidence of the occurrence of a range expansion (RE) originating close to the Indo-Australian Archipelago (IAA) where two stepping-stone waves (east and westward) colonized almost the entire IP. Coalescent modeling additionally highlighted a homogenous connectivity (Nm~10 per generation) throughout the range, and an isolation by distance model suggested the absence of barriers to dispersal despite the affinity of C. amblyrhynchos to coral reefs. This coincides with long-distance swims previously recorded, suggesting that the strong genetic structure at the IP scale (FST ~ 0.56 between its ends) is the consequence of its broad current distribution and organization in a large number of demes. Our results strongly suggest that management plans for the grey reef shark should be designed on a range-wide rather than a local scale due to its continuous genetic structure. We further contrasted these results with those obtained previously for the sympatric but strictly lagoon-associated Carcharhinus melanopterus, known for its restricted dispersal ability. C. melanopterus exhibits similar RE dynamic, but is characterized by stronger genetic structure and a non-homogeneous connectivity largely dependent on local coral reefs availability. This sheds new light on shark evolution, emphasizing the roles of IAA as source of biodiversity and of life history traits in shaping the extent of genetic structure and diversity.
06 Oct 2022Submitted to Ecology and Evolution
07 Oct 2022Submission Checks Completed
07 Oct 2022Assigned to Editor
07 Oct 2022Review(s) Completed, Editorial Evaluation Pending
07 Oct 2022Reviewer(s) Assigned
16 Nov 2022Editorial Decision: Accept
22 Nov 20221st Revision Received
23 Nov 2022Submission Checks Completed
23 Nov 2022Assigned to Editor
23 Nov 2022Review(s) Completed, Editorial Evaluation Pending
27 Nov 2022Editorial Decision: Revise Minor
18 Dec 20222nd Revision Received
19 Dec 2022Review(s) Completed, Editorial Evaluation Pending
19 Dec 2022Submission Checks Completed
19 Dec 2022Assigned to Editor
27 Dec 2022Editorial Decision: Accept