Genetic connectivity and phylogeography of the night shark (Carcharhinus signatus) in the western Atlantic Ocean: Implications for conservation management

Rodrigo R. Domingues, Christine C. Bruels, Otto B.F. Gadig, Demian D. Chapman, Alexandre W.S. Hilsdorf, Mahmood S. Shivji

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The night shark, Carcharhinus signatus, is a mesopelagic, semi-oceanic shark species found only in the Atlantic Ocean. It is one of the most frequently caught sharks in pelagic longline fisheries and is classified as Vulnerable by the International Union for the Conservation of Nature (IUCN). Despite their prevalence in commercial fisheries, the population genetic structure of the night shark has not been assessed. The present study investigated the genetic diversity, genetic connectivity, and phylogeography of the species throughout the western Atlantic Ocean, based on complete mitochondrial control region (mtCR) sequence data (n = 152) and genotypic data from nine nuclear microsatellites (n = 119). The mtCR sequence revealed 19 haplotypes, with overall haplotype and nucleotide diversities of 0.74 (±0.027) and 0.0034 (±0.0019), respectively, whereas the nuclear microsatellite observed and expected heterozygosities were 0.408 and 0.421, respectively. There was significant population structure (Ф ST  = 0.429; P < 0.01) and isolation by distance (r = 0.65, P = 0.03) based on mtCR sequence data, but no genetic differentiation based on nuclear microsatellite analyses. The phylogenetic analyses support the existence of two matrilineal lineages, which diverged during the Pleistocene. Mitochondrial demographic analyses indicated a historical bottleneck effect followed by population expansion during the Pleistocene, whereas nuclear microsatellites did not detect a recent or a strong bottleneck. For conservation purposes, we advocate that the species should be considered to comprise at least two management units (MUs) in the western Atlantic Ocean. MU-specific catch quotas should be implemented throughout the range of the species given its low genetic diversity and vulnerability to overexploitation.

Original languageEnglish (US)
Pages (from-to)102-114
Number of pages13
JournalAquatic Conservation: Marine and Freshwater Ecosystems
Volume29
Issue number1
DOIs
StatePublished - Jan 2019
Externally publishedYes

Bibliographical note

Funding Information:
This work was developed as part of the requirements for the PhD dissertation of author RRD in Zoology at the Sao Paulo State University – UNESP. This work was funded by the São Paulo Research Foundation (FAPESP #2009/59660‐6 and #2013/08675‐7), FAEP (Fundação de Apoio ao Ensino e Pesquisa), the Save Our Seas Foundation and the Guy Harvey Ocean Foundation. The collection of samples from Belize was funded by the Roe Foundation. We also are grateful to Patricia Mancini, Fabio Hazin, Debra Abercombrie, Christina Conrath, Brian Gervelis, Freddy Arocha, Mike Heithaus, Alberto Amorim, and the staff of the National Marine Fisheries Service (NMFS) Panama City Observer Program, for generously providing night shark samples.

Funding Information:
This work was developed as part of the requirements for the PhD dissertation of author RRD in Zoology at the Sao Paulo State University ? UNESP. This work was funded by the S?o Paulo Research Foundation (FAPESP #2009/59660-6 and #2013/08675-7), FAEP (Funda??o de Apoio ao Ensino e Pesquisa), the Save Our Seas Foundation and the Guy Harvey Ocean Foundation. The collection of samples from Belize was funded by the Roe Foundation. We also are grateful to Patricia Mancini, Fabio Hazin, Debra Abercombrie, Christina Conrath, Brian Gervelis, Freddy Arocha, Mike Heithaus, Alberto Amorim, and the staff of the National Marine Fisheries Service (NMFS) Panama City Observer Program, for generously providing night shark samples.

Publisher Copyright:
© 2018 John Wiley & Sons, Ltd.

Keywords

  • conservation evaluation
  • dispersal
  • fish
  • fisheries management
  • gene flow
  • genetic diversity

Fingerprint

Dive into the research topics of 'Genetic connectivity and phylogeography of the night shark (Carcharhinus signatus) in the western Atlantic Ocean: Implications for conservation management'. Together they form a unique fingerprint.

Cite this