Discordant patterns of genetic connectivity between two sympatric species, Mullus barbatus (Linnaeus, 1758) and Mullus surmuletus (Linnaeus, 1758), in south-western Mediterranean Sea F.C. Félix-Hackradt a, * , C.W. Hackradt a , Á. Pérez-Ruzafa a, b , J.A. García-Charton a a Departmento de Ecología e Hydrologia, Universidad de Murcia, Campus Espinardo, 30100 Murcia, Spain b Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, Murcia, Spain article info Article history: Received 14 May 2013 Received in revised form 6 August 2013 Accepted 8 August 2013 Keywords: Mullets Coastal zone Population connectivity Geomorphological features Currents Habitat Marine protected areas Post-larvae abstract Population connectivity scales are important tools to achieve a mechanistic understanding of the factors regulating the abundance and distribution of marine populations and therefore support conservation actions to manage fisheries and stocks. We used 10 microsatellites markers on mullets’ samples across the Spanish coast to determine the spatial scale of gene flow as well as the origin of post-larvae caught inside two MPAs. Population structure varied from complete homogeneity for Mullus barbatus, to high spatial variability in Mullus surmuletus samples. Differential habitat utilization by species, geomorpho- logical features and oceanographic patterns are discussed as potential causes of patterns observed. Although we were unable to verify the origin of most post-larvae caught inside MPAs we suggest that they may act as genetic reservoirs due to high heterozigosity levels found in adult specimens inside (M. surmuletus) and nearby (both) them. Our results indicate that early life history traits (i.e. larvae) may not be the only determinant on species dispersal capability, suggesting that other mechanisms such as fine scale adult or juvenile movement may have been underestimated as promoting population connectivity. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Stripped red mullet (Mullus surmuletus, Linnaeus, 1758) and red mullet (Mullus barbatus, Linnaeus, 1758) are distributed in the Eastern Atlantic Sea from North Sea to Senegal as well as throughout the Mediterranean and Black seas (Whitehead et al., 1986). Both are demersal fishes and share very similar biological characteristics (Mamuris et al., 1998); both species spawn in spring, and their larvae and juveniles are pelagic. Notwithstanding, they differ in their habitat preference: while M. surmuletus is mostly found on rough bottoms, M. barbatus instead prefers sandy or/and muddy habitats (Tserpes et al., 2002). Although both species occur at depths ranging from 10 to 300 m, Lombarte et al. (2000) described a preference of Mullus sumuletus to occur in narrow continental shelf areas with rocky or sandy bottoms, while M. barbatus shows a clear preference for areas with a wider con- tinental shelf. Both species are considered important resources for coastal Mediterranean demersal fisheries (Reñones et al., 1995) as they are among the most valuable species in commercial landings. They are caught mainly by trawling fleet (Tserpes et al., 2002) and thus subject to intense fishing pressure. Trawl catches are composed mainly of individuals 15e20-cm in length which corresponds to 1st and 2nd year classes (Reñones et al., 1995), meaning that mullet stocks are composed mainly by young fish (Tserpes et al., 2002) and thus they are highly susceptible to overfishing. Due to their economic importance, considerable knowledge of mullet biology has been acquired in the past years. Studies on growth and reproduction (Tursi et al., 1994; Reñones et al., 1995; Özbilgin et al., 2004), distribution patterns (Lombarte et al., 2000; Tserpes et al., 2002), feeding and ontogenetic behaviour (Vassilopoulou and Papaconstantinou, 1993; Labropoulou et al., 1997) and movement strategies (Machias et al., 1998) have contributed significantly to the knowledge of both species. Also, a number of comparative works between the two species added substantial information about genetic population structure and variability across Mediterranean localities. RAPD, allozymes and * Corresponding author. Present address: Departamento de Engenharia e Meio Ambiente, Centro de Ciências Aplicadas e Educação, Universidade Federal da Par- aíba, Rua da Mangueira S/N, 58109-753 Rio Tinto, Paraíba, Brazil. Tel.: þ55 83 8847 1171. E-mail address: felixhackradtfc@gmail.com (F.C. Félix-Hackradt). Contents lists available at ScienceDirect Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev 0141-1136/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.marenvres.2013.08.008 Marine Environmental Research xxx (2013) 1e12 Please cite this article in press as: Félix-Hackradt, F.C., et al., Discordant patterns of genetic connectivity between two sympatric species, Mullus barbatus (Linnaeus,1758) and Mullus surmuletus (Linnaeus,1758), in south-western Mediterranean Sea, Marine Environmental Research (2013), http://dx.doi.org/10.1016/j.marenvres.2013.08.008