Mitochondrial DNA and microsatellite genetic differentiation in the European anchovy Engraulis encrasicolus L.

Borrell, Y. J., Piera, J. A., Sanchez Prado, J. A., and Blanco, G. 2012. Mitochondrial DNA and microsatellite genetic differentiation in the European anchovy Engraulis encrasicolus L. ICES Journal of Marine Science, 69: . The European anchovy Engraulis encrasicolus is currently one of the principal target species for commercial fisheries in Europe, and most stocks are overfished at present. In this work, specimens were sampled in the Bay of Biscay (Cantabrian, Basque Country, and French coasts) in 2009 and also in the Mediterranean (Adriatic Sea). Mitochondrial DNA (mtDNA; cytochrome b and 16S) was sequenced, and 14 nuclear microsatellites showing high and low levels of polymorphism were arranged in three multiplex polymerase chain reaction (PCR) systems and genotyped. Two main ancient mitochondrial clades were found. These clades are separated by 15 mutational steps and 1.7 sequence divergence, corresponding to a separation time of approximate to 0.5 million years ago. Our results using both mtDNA and microsatellites suggest the presence of at least three genetically differentiated groups: the west Cantabrian Sea, the rest of the populations in the Bay of Biscay, and the Mediterranean. Although it is known that western Iberian Atlantic populations of E. encrasicolus may be genetically different from those of the Bay of Biscay, the results suggest that the transition between these groups may be as close as a 100 km and that a recent genetic homogenization process in the eastward area of the Bay of Biscay has probably occurred.