Effective population size of the critically endangered east Australian grey nurse shark Carcharias taurus

Sarah Reid-Anderson, Kerstin Bilgmann, Adam Stow

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Retaining genetic variation is central to species-level conservation, and knowledge of effective population sizes (Ne) can be used to predict rates at which genetic variation will be lost over generations. Here we used thousands of genome-wide single nucleotide polymorphisms to investigate Ne of the critically endangered grey nurse shark Carcharias taurus across 1400 km of its eastern Australian range. The eastern Australian grey nurse shark population has declined rapidly in number over the last few decades, has relatively low genetic diversity and is extremely susceptible to anthropogenic mortality. We found no evidence for any genetic structure, which is consistent with previous field observations that show widespread movement across the distribution. Estimates of the effective number of breeders (Nb) and Ne were around 400, using an approach based on proportions of siblings and another based on linkage disequilibrium. Forward simulations revealed that even if an Ne of 400 is maintained, the population will experience some loss of genetic diversity over the next 50 generations. The relatively low Ne highlights the importance of maintaining the population size of grey nurse sharks in order to retain genetic variation and therefore resilience to environmental change.
LanguageEnglish
Pages137–148
Number of pages12
JournalMarine Ecology Progress Series
Volume610
DOIs
Publication statusPublished - 1 Feb 2019

Fingerprint

Ginglymostoma cirratum
Carcharias
effective population size
shark
genetic variation
population size
disequilibrium
genetic structure
environmental change
polymorphism
genome
mortality
linkage disequilibrium
single nucleotide polymorphism
simulation
genetic diversity

Bibliographical note

© Inter-Research 2019. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Ne
  • effective number of breeders
  • genetic panmixia
  • shark
  • conservation
  • simulation
  • single nucleotide polymorphisms

Cite this

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abstract = "Retaining genetic variation is central to species-level conservation, and knowledge of effective population sizes (Ne) can be used to predict rates at which genetic variation will be lost over generations. Here we used thousands of genome-wide single nucleotide polymorphisms to investigate Ne of the critically endangered grey nurse shark Carcharias taurus across 1400 km of its eastern Australian range. The eastern Australian grey nurse shark population has declined rapidly in number over the last few decades, has relatively low genetic diversity and is extremely susceptible to anthropogenic mortality. We found no evidence for any genetic structure, which is consistent with previous field observations that show widespread movement across the distribution. Estimates of the effective number of breeders (Nb) and Ne were around 400, using an approach based on proportions of siblings and another based on linkage disequilibrium. Forward simulations revealed that even if an Ne of 400 is maintained, the population will experience some loss of genetic diversity over the next 50 generations. The relatively low Ne highlights the importance of maintaining the population size of grey nurse sharks in order to retain genetic variation and therefore resilience to environmental change.",
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Effective population size of the critically endangered east Australian grey nurse shark Carcharias taurus. / Reid-Anderson, Sarah; Bilgmann, Kerstin; Stow, Adam.

In: Marine Ecology Progress Series, Vol. 610, 01.02.2019, p. 137–148.

Research output: Contribution to journalArticleResearchpeer-review

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