Genetic differentiation and phylogeography of Mediterranean-North Eastern Atlantic blue shark ( Prionace glauca , L. 1758) using mitochondrial DNA: panmixia or complex stock structure?

PeerJ

article

Agostino Leone¹  Ilenia Urso¹  Dimitrios Damalas²  Jann Martinsohn²  Antonella Zanzi²  Stefano Mariani⁴  Emilio Sperone⁵  Primo Micarelli⁶  Fulvio Garibaldi⁷  Persefoni Megalofonou⁸  Luca Bargelloni⁹  Rafaella Franch⁹  David Macias^1,10  Paulo Prodöhl^1,11  Séan Fitzpatrick^1,11  Marco Stagioni^1,12  Fausto Tinti¹  Alessia Cariani¹ 

[1] Department of Biological, Geological and Environmental Sciences ,(BiGeA), Laboratory of Genetics & Genomics of Marine Resources and Environment ,(GenoDREAM), University of Bologna;Joint Research Centre;Hellenic Centre for Marine Research;School of Environment & Life Sciences, University of Salford;Department of Biology, Ecology and Earth Science ,(DiBEST), University of Calabria;Sharks Research Center;Department of Earth, Environment and Life Sciences, University of Genova;Department of Biology, National and Kapodistrian University of Athens;Department of Comparative Biomedicine and Food Science, University of Padova;Centro Oceanográfico de Málaga, Instituto Español de Oceanografía;School of Biological Sciences, Queen’s University, Institute for Global Food Security;Department of Biological, Geological and Environmental Sciences, Marine Biology and Fisheries Laboratory, University of Bologna

关键词: mtDNA;    Population expansion;    Blue shark;    Phylogeography;    Geographical breaks;    Mediterranean stocks;    Sharks;   

DOI  :  10.7717/peerj.4112

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundThe blue shark (Prionace glauca, Linnaeus 1758) is one of the most abundant epipelagic shark inhabiting all the oceans except the poles, including the Mediterranean Sea, but its genetic structure has not been confirmed at basin and interoceanic distances. Past tagging programs in the Atlantic Ocean failed to find evidence of migration of blue sharks between the Mediterranean and the adjacent Atlantic, despite the extreme vagility of the species. Although the high rate of by-catch in the Mediterranean basin, to date no genetic study on Mediterranean blue shark was carried out, which constitutes a significant knowledge gap, considering that this population is classified as “Critically Endangered”, unlike its open-ocean counterpart.MethodsBlue shark phylogeography and demography in the Mediterranean Sea and North-Eastern Atlantic Ocean were inferred using two mitochondrial genes (Cytb and control region) amplified from 207 and 170 individuals respectively, collected from six localities across the Mediterranean and two from the North-Eastern Atlantic.ResultsAlthough no obvious pattern of geographical differentiation was apparent from the haplotype network, Φst analyses indicated significant genetic structure among four geographical groups. Demographic analyses suggest that these populations have experienced a constant population expansion in the last 0.4–0.1 million of years.DiscussionThe weak, but significant, differences in Mediterranean and adjacent North-eastern Atlantic blue sharks revealed a complex phylogeographic structure, which appears to reject the assumption of panmixia across the study area, but also supports a certain degree of population connectivity across the Strait of Gibraltar, despite the lack of evidence of migratory movements observed by tagging data. Analyses of spatial genetic structure in relation to sex-ratio and size could indicate some level of sex/stage biased migratory behaviour.

【 授权许可】

CC BY