J.L.Y.Spaet, R.W. Jabado, A.C. Henderson, A.B.M. Moore, M.L. Berumen
Ecology and Evolution, volume 5, issue 12, pp. 2317-2332, (2015)
Carcharhinus limbatus, Carcharhinus sorrah, Connectivity, Elasmobranchs, Rhizoprionodon acutus, Sphyrna lewini.
The northwestern Indian Ocean harbors a number of larger marine
vertebrate taxa that warrant the investigation of genetic population
structure given remarkable spatial heterogeneity in biological
characteristics such as distribution, behavior, and morphology. Here, we
investigate the genetic population structure of four commercially
exploited shark species with different biological characteristics (Carcharhinus limbatus, Carcharhinus sorrah, Rhizoprionodon acutus, and Sphyrna lewini)
between the Red Sea and all other water bodies surrounding the Arabian
Peninsula. To assess intraspecific patterns of connectivity, we
constructed statistical parsimony networks among haplotypes and
estimated (1) population structure; and (2) time of most recent
population expansion, based on mitochondrial control region DNA and a
total of 20 microsatellites. Our analysis indicates that, even in
smaller, less vagile shark species, there are no contemporary barriers
to gene flow across the study region, while historical events, for
example, Pleistocene glacial cycles, may have affected connectivity in C. sorrah and R. acutus. A parsimony network analysis provided evidence that Arabian S. lewini
may represent a population segment that is distinct from other known
stocks in the Indian Ocean, raising a new layer of conservation concern.
Our results call for urgent regional cooperation to ensure the
sustainable exploitation of sharks in the Arabian region.