Différenciation génétique associée aux phénomènes de migration lessepsienne : exemple de Siganus rivulatus, S. luridus et Upeneus moluccensis

• Mohamad Hassan
• The Regional Workshop on Marine Sciences & Natural Resources 25-26 May 2004.

Abstract

Since the opening of the Suez Canal in the nineteenth century, a growing number of teleosts species have become permanently established in the eastern Mediterranean. As environmental parameters in the Mediterranean are very different from those in the Red Sea, there is an opportunity to evaluate the gene flow associated with the acclimatisation of these species to their new environment. Initial colonisation may have been restricted to individuals with marginal genotypes compared to populations of the Red Sea, eventually better adapted to the Mediterranean environment. Alternatively, colonisation may have occurred without major genetic differentiation, due to a large flux of immigrants and a continuous gene flow from the populations of origin. Using different molecular genetic techniques (mitochondrial DNA, Exon-Primed Intron-Crossing PCR amplification (EPIC) and Inter-Simple Sequence Repeats (ISSRs), patterns of genetic differentiation on both sides of the Suez isthmus were tested on three Lessepsian rabbitfish species, Siganus rivulatus, S. luridus and a mullid species, Upeneus moluccensis. The absence of genetic differentiation between Mediterranean and Red Sea populations in both species showed that a great number of migrants participated to the colonisation of the Mediterranean, excluding any bottleneck event. This colonisation success suggests large eco-physiological plasticity in Siganus rivulatus, S. luridus and Upeneus moluccensis that allowed them to thrive in the new environment.

Key words: Bottleneck; Invasion; Lessepsian migration; Siganus luridus; S. rivulatus; Upeneus moluccensis.