S. Mgeleka, M. Silas, Cretus Mtonga, C. Rumisha, Elina Viinamäki, P. Polte, M. Sköld, M. Winder, M. Gullström
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引用次数: 0
Abstract
ABSTRACT The hound needlefish Tylosurus crocodilus (Belonidae) is a highly demanded fish in the local markets of Tanzania, but the growing coastal population threatens its sustainability. As belonids are highly migratory fishes utilising various parts of the seascape, increased fishing pressure may disrupt connectivity patterns on different spatiotemporal scales and disaggregate populations. Using the COI gene, this study assessed the genetic population structure, connectivity patterns, and historical demography of T. crocodilus collected in seven sites spread along Tanzanian coastal waters. Results showed fourteen haplotypes with low overall nucleotide and haplotype diversity. Pairwise FST comparisons revealed no significant differences among the sampled sites, except for the northernmost site (Tanga) and an island in the south (Songosongo). Analysis of molecular variance (AMOVA) revealed a non-significant genetic structure among populations (FST = 0.01782), suggesting the fishery across Tanzanian waters exploits the same population. Moreover, there was no correlative relationship between genetic and pairwise geographic distances, rejecting the isolation by distance hypothesis. However, neutrality tests and mismatch distribution analysis revealed that recent demographic expansion might exist. Empirical evidence of panmixia suggests high genetic connectivity. In combination with low genetic diversity, management should be directed to actions that prevent genetic diversity loss and the effect of genetic drift on populations.
期刊介绍:
Marine Biology Research (MBRJ) provides a worldwide forum for key information, ideas and discussion on all areas of marine biology and biological oceanography. Founded in 2005 as a merger of two Scandinavian journals, Sarsia and Ophelia, MBRJ is based today at the Institute of Marine Research, Bergen, Norway. The Journal’s scope encompasses basic and applied research from all oceans and marine habitats and on all marine organisms, the main criterium for acceptance being quality.