Current genetic status of common carp (Cyprinus carpio L.) introduced into Tunisian reservoirs
In order to enhance and develop inland fisheries and to create exploratory ichthyic stocks in reservoirs, the introduction of freshwater fishes in Tunisia began since the 1960s. However, stocking programs are usually conducted without any following assessment of the potential success of the exercise. Within the context of studying the genetic status of introduced populations, this paper describes the genetic variation of two domesticated varieties of common carp, scaly and mirror, introduced into five Tunisian reservoirs using six allozyme and four microsatellite loci. Although the genetic diversity observed with microsatellites was higher than that observed with allozyme markers, it remained lower compared to wild European populations. The lowest genetic diversity was observed in the mirror carp population of Nebhana reservoir. Both marker types highlighted significant heterogeneity among the two mirror carp populations and between the two varieties except between the two sympatric scaly and mirror carp populations of Sidi Salem reservoir. Nebhana population was found to be the most differentiated and this can be explained by genetic differences that already exist between the introduced populations, and which were increased by genetic drift and/or selection. Within scaly carp populations, homogeneity was revealed only between populations of the Mellegue and Bir M’cherga reservoirs. The significant differentiation of the scaly carp population of Sidi Salem reservoir might be due to hybridization with mirror carp sympatric in this reservoir.