Genetic connectivity of a coral reef ecosystem predator: the population genetic structure and evolutionary history of the Caribbean reef shark (Carcharhinus perezi). (26th July 2017)

• Record Type: Journal Article
• Authors: Bernard, Andrea M.; Horn, Rebekah L.; Chapman, Demian D.; Feldheim, Kevin A.; Garla, Ricardo C.; Brooks, Edd J.; Gore, Mauvis A.; Shivji, Mahmood S.
• Is Part Of: Journal of biogeography. Volume 44:Number 11(2017:Nov.)
• Page Start: 2488
• Page End: 2500
• Publication Date: 2017-07-26
• Subjects: coral reefs -- elasmobranch -- evolutionary history -- marine biogeography -- microsatellite DNA -- mitochondrial DNA -- population structure -- western Atlantic; Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.13062
• Languages: English
• ISSNs: 0305-0270

Abstract

Abstract: Aim: The Caribbean reef shark ( Carcharhinus perezi ) is one of few extant reef sharks inhabiting the Atlantic Ocean. Its variability in movements across habitat types suggests the possibility of a complex genetic population structure. Here, we use mitochondrial and nuclear DNA to investigate the genetic connectivity of the Caribbean reef shark across contemporary and evolutionary time‐scales and relate our findings to the ecology of this understudied species. Location: Tropical western Atlantic and Caribbean. Methods: Samples were obtained from 216 individuals from six western Atlantic and Caribbean locations. Individuals were genotyped at seven nuclear microsatellite DNA loci and sequenced at two mitochondrial (control region [CR]; NADH dehydrogenase subunit 4 [ND4]) and one nuclear locus (lactate dehydrogenase [LDH]). Analyses to resolve the population genetic structure and evolutionary history of this species were adopted. Results: Sequencing of the CR (1, 068 bp, n = 216), ND4 (741 bp, n = 213) and LDH (258 bp, n = 165) loci, resolved 11, 8 and 13 unique haplotypes (or alleles), respectively. Overall, Caribbean reef sharks showed low levels of genetic diversity and most marker sets identified strong genetic differences ( F ST and ΦST ) between sharks sampled in Brazil versus all other locations (msat F ST > 0.017; CR‐ND4 ΦST > 0.013). Mitochondrial DNA showed evidence of increased genetic partitioning among western North Atlantic sampling sites, although widespread haplotype sharing (~85%–92%) and a shallow population history were found. Main Conclusions: Findings of genetic differentiation are concordant with previous movement studies showing residency and/or site‐fidelity to specific locations by individuals. However, similar to other reef shark studies, we found that the level of genetic connectivity among populations was context dependent—i.e., sharks occupying isolated habitats showed greater genetic differentiation compared with those sharks occupying semi‐isolated or continuous reef habitats. Furthermore, low genetic diversity and a shallow mitochondrial population history were found, suggesting historical demographic fluctuations, including population collapse and more recent expansions.