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

PeerJ

David Macias¹  Ilenia Urso²  Alessia Cariani²  Fausto Tinti²  Agostino Leone²  Marco Stagioni³  Emilio Sperone⁴  Persefoni Megalofonou⁵  Luca Bargelloni⁶  Rafaella Franch⁶  Fulvio Garibaldi⁷  Antonella Zanzi⁸  Dimitrios Damalas⁸  Jann Martinsohn⁸  Séan Fitzpatrick⁹  Paulo Prodöhl⁹  Stefano Mariani^1,10  Primo Micarelli^1,11 

[1] Centro Oceanográfico de Málaga, Instituto Español de Oceanografía, Málaga, Spain;Department of Biological, Geological and Environmental Sciences (BiGeA), Laboratory of Genetics & Genomics of Marine Resources and Environment (GenoDREAM), University of Bologna, Ravenna, Italy;Department of Biological, Geological and Environmental Sciences, Marine Biology and Fisheries Laboratory, University of Bologna, Fano, Italy;Department of Biology, Ecology and Earth Science (DiBEST), University of Calabria, Arcavacata di Rende, Italy;Department of Biology, National and Kapodistrian University of Athens, Ilissia, Greece;Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy;Department of Earth, Environment and Life Sciences, University of Genova, Genova, Italy;Joint Research Centre (JRC), Directorate D-Sustainable Resources, Unit D2-Water and Marine Resources, European Commission, Ispra, Italy;School of Biological Sciences, Queen’s University, Institute for Global Food Security, Belfast,United Kingdom;School of Environment & Life Sciences, University of Salford, Salford, Greater Manchester, United Kingdom;Sharks Research Center, Aquarium Mondo Marino, Massa Marittima, Italy;

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

DOI  :  10.7717/peerj.4112

来源: DOAJ

【 摘 要 】

Background The 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. Methods Blue 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. Results Although 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. Discussion The 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】

Unknown