Genetic characterization of sharpsnout seabream (Diplodus puntazzo) populations along the Tunisian coasts
In order to improve our knowledge about the genetic diversity of Tunisian sharpsnout seabream, Diplodus puntazzo (Walbaum, 1792), populations along a boundary area between western and eastern Mediterranean basins, eight Tunisian samples were studied, using inter-simple sequence repeat (ISSR) markers. Ten ISSR primers produced 128 bands in all analysed samples with a high polymorphic rate (100%). The total genetic diversity was attributed mainly to the within-population variation. The analysis of genetic variation among populations showed an overall heterogeneity among Tunisian samples. Discriminant Analysis of Principal Components (DAPC) allowed the distinction of the island sample of Kerkennah and the clustering of the other ones into two groups: northeastern (Bizerta Bay, Ghar El Melh lagoon and Tunis Gulf + eastern sample of Monastir) and southeastern (eastern sample of Chebba + Zarzis and El Biban lagoon) groups. This pattern reflects the oceanographic features and the heterogeneity of physicochemical parameters between the both sides of this transition area but also within the southeastern sector (Gabès Gulf). Moreover, species’ life-history traits, such as the sedentary life-style and the short duration of the larval stage, can contribute to shape the pattern of the genetic structure of sharpsnout seabream populations along the Tunisian coasts.