Frontiers in Marine Science (Nov 2015)
West Pike Story: a dated phylogeography of Esox spp. (Actinopterygii, Esocidae)
Abstract
With only one species of pike in Europe (Esox lucius Linnaeus, 1758), Esox systematics was considered settled for decades. However recent taxonomical studies of European pikes led to the discovery of two new species: Esox cisalpinus Bianco & Delmastro, 2011 from Northern and Central Italy, and Esox aquitanicus Denys et al. 2014 in the South-West of France. Within E. lucius sensu stricto, three different evolutionary lineages were identified with mitochondrial markers, a North-European, a South-European (Danubian), and a circumpolar lineage (Skog et al., 2014). French Northern pike belongs to the North-European lineage, but it is commonly reared in ponds and traded since the Middle Age at least, and it is widely stocked in open waters since the second half of the 20th century, leading to introgression with native populations (Launey et al., 2006). E. cisalpinus is similarly threatened by the non-native E. lucius (Gandolfi et al., 2014). Previous studies on pikes mostly used various mitochondrial loci, leading to dataset dispersion. We then developed a mitogenomic approach proved efficient for Teleost systematics in the last 15 years (Miya & Nishida, 2015). This study unifies fine-scale pike phylogeography using the complete mitochondrial genome for 13 E. lucius, 6 E. aquitanicus and 2 E. cisalpinus samples. The results distinguish the 3 pike species as well as the 3 lineages of E. lucius from Skog et al. (2014). The presence of individuals from the South-European and circumpolar lineages might result from stocking operations. Finally, molecular dating with reanalysis old fossil calibrations places the European pikes diversification during the late Miocene (E. aquitanicus vs. the others), the late Pliocene (E. cisalpinus vs. E. lucius), and the Pleistocene ice ages (E. lucius lineages). Pike restocking should take into account the genetics of the fish in order to preserve these species with high economical and patrimonial value.
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