Fisheries Research 174 (2016) 245–249 Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/fishres Short communication Population genetic structure of the European conger (Conger conger) in North East Atlantic and West Mediterranean Sea Laura Miralles ∗ , Ling S. Lee, Yaisel Borrell, Eva Garcia-Vazquez Department of Functional Biology, University of Oviedo, C/ Julian Claveria s/n, 33006 Oviedo, Spain a r t i c l e i n f o Article history: Received 29 May 2015 Received in revised form 5 October 2015 Accepted 9 October 2015 Keywords: Congridae Microsatellite Population genetics Atlantic Mediterranean a b s t r a c t Assessment of population genetic structure is crucial in species conservation and stock management. The use of multiple markers is recommended to obtain accurate studies. In this study, a panel of five microsatellite loci described for Conger myriaster was optimized for the European conger eel Conger conger. These are the first hypervariable nuclear loci employed for C. conger population study and have a high discrimination power. A total of 67 alleles were observed for Atlantic and Mediterranean samples with an average number of alleles per locus of 13.4 (range 4–24). Variation at these microsatellite loci was combined with mitochondrial control region sequences (395 bp) to explore genetic structure of C. conger across the Cantabrian Sea (North East Atlantic ocean) and the West Mediterranean Sea. Overall, there is not total isolation between the Atlantic and the Mediterranean stocks, as previously suggested in other studies, but a subtle differentiation. Cross-species amplification of microsatellite loci in C. conger is hoped to encourage further population studies of this species and the development of new nuclear markers in order to provide scientific advice for the stock management. © 2015 Elsevier B.V. All rights reserved. 1. Introduction The European conger eel (Conger conger) is distributed across coastal shelves and slopes in the eastern North Atlantic Ocean, Mediterranean and Black seas (Bauchot and Saldanha, 1986). The species matures sexually and spawns in offshore deep waters (e.g. Cau and Manconi, 1983; Sbaihi et al., 2001). Two spawning grounds are reported for C. conger. in the Mediterranean Sea along the Sardinian channel (Cau and Manconi, 1983) and in the Northeast Atlantic between Gibraltar and the Azores (e.g. Correia et al., 2002, 2003). Larvae exhibit high dispersal capacity, but no information is available about the migration routes of juveniles and adults (Correia et al., 2011). Current bibliography about C. conger shows the knowledge about genetic population structure is limited as well (e.g. Correia et al., 2002, 2003, 2006, 2009, 2011, 2012). A previous study of C. conger leptocephali based on mtDNA revealed high hap- lotype diversity and significant geographic differentiation at local level (Correia et al., 2006). A latter study based on otoliths chem- istry and mtDNA suggested a separate replenishment source for western Mediterranean and North East Atlantic stocks, with lim- ited connectivity (Correia et al., 2012). These genetic inferences ∗ Corresponding author. Fax: +34 985103534. E-mail address: lml.miralles@gmail.com (L. Miralles). have essentially relied on mitochondrial rather than nuclear data, which may restrict the interpretation of results in case of histor- ical population changes and/or sex-biased (mitochondrial DNA is female inherited) demographic dynamics (Fauvelot et al., 2003). At present, nuclear DNA analysis has never been attempted for C. conger. The main objective of the present study was to use nuclear genetic information (microsatellite loci) to infer population struc- ture in West Mediterranean and North East Atlantic conger populations. For that aim, we tested cross-species amplification and optimization on C. conger of five pairs of microsatellite primers developed for the Japanese conger Conger myriaster (Kimura et al., 2003). Furthermore, the mtDNA control region was also employed to infer levels of heterogeneity and to compare with available lit- erature (Correia et al.2006). 2. Materials and methods 2.1. Fish collection and study area A total of 79 mature individuals were sampled in 3 locations (S.I.: Fig. S1). Two in Asturias, North Spain: Gijón (G) and Villavi- ciosa (V) from April to June 2013, during spearfishing tournaments held by FEDAS (Spanish Federation of Underwater Activities) where the fishing area was about 26 km in length, 2 km in width and a http://dx.doi.org/10.1016/j.fishres.2015.10.013 0165-7836/© 2015 Elsevier B.V. All rights reserved.