**4. Discussion**

116 Aquaculture

the three sampling sites of *F. glaber* and *F. proteus* respectively, the exact test of population

Mismatch distribution was calculated for all studied populations of both taxa (Fig. 5). All populations followed unimodal distribution (i.e a bell-shaped distribution) that it is assumed to be the signature of population expansion occurred probably after a bottleneck event. However, Tajima's *D*-values were not significantly negative for any of the studied

Fig. 5. Mismatch distributions for A) *F. glaber* and B) *F. proteus*. All studied samples followed the same unimodal distribution and thus graphs depict frequencies of pairwise differences for one of the populations of each taxon. The observed frequency of pairwise nucleotide differences among sequences is represented by black bars, and expected frequencies under a

model of sudden population expansion are represented by continuous line.

differentiation was still not statistically significant (*P* values=0.20).

populations (p=0.05–0.1), thus rejecting the hypothesis for population growth.
