This study formed part of H.A’s MSc research on the conservation genetics of grey nurse shark. R.G.H. specializes in ecology and conservation of large marine predators. He is particularly interested in large-scale movements, interactions between populations and evolution of and influences of mating systems on population persistence. A.J.S. has diverse interests in conservation genetics, ecology and biodiversity of marine and terrestrial fauna. His interests include the development of molecular ecological techniques to advance conservation practice.
Nuclear and mitochondrial DNA reveals isolation of imperilled grey nurse shark populations (Carcharias taurus)
Article first published online: 5 OCT 2009
© 2009 Blackwell Publishing Ltd
Volume 18, Issue 21, pages 4409–4421, November 2009
How to Cite
AHONEN, H., HARCOURT, R. G. and STOW, A. J. (2009), Nuclear and mitochondrial DNA reveals isolation of imperilled grey nurse shark populations (Carcharias taurus). Molecular Ecology, 18: 4409–4421. doi: 10.1111/j.1365-294X.2009.04377.x
- Issue published online: 14 OCT 2009
- Article first published online: 5 OCT 2009
- Received 18 June 2009; revision received 20 August 2009; accepted 22 August 2009
- evolutionary significant unit;
- International Union for the Conservation of Nature;
- population differentiation;
Loss of sharks and other upper-trophic marine predators has sparked worldwide concern for the stability of ocean ecosystems. The grey nurse (ragged-tooth or sand tiger) shark (Carcharias taurus) is Vulnerable on a global scale, Critically Endangered in Australia and presumed extinct in parts of its historical range. We used 193 muscle and fin samples collected from six extant populations to assess global mtDNA and microsatellite diversity and the degree of global population genetic structure. Control region mtDNA diversity was low in every population, and two populations (eastern Australia and Japan) contained only a single mtDNA haplotype. Genetic signatures of recent losses of genetic variation were not yet apparent at microsatellite loci, indicating that this low mtDNA variation is not a result of anthropogenic population declines. Population differentiation was substantial between each population pair except Brazil and South Africa, FST values ranged from 0.050 to 0.699 and 0.100 to 1.00 for microsatellite and mitochondrial data respectively. Bayesian analysis clearly partitioned individuals into five of the populations from which they were sampled. Our data imply a low frequency of immigrant exchange among each of these regions and we suggest that each be recognized as a distinct evolutionary significant unit. In contrast to pelagic species such as whale shark and white shark that may cross ocean basins and where cooperative international efforts are necessary for conservation, grey nurse shark, like many coastal species, need to be managed regionally.