Phylogenetic relationships in grey mullets (Mugilidae) in a Tunisian lagoon (original) (raw)

2008, Aquaculture Research

The Mugilidae family is an important ¢sh group representing a major source for ¢sheries and aquaculture. In the south Mediterranean bank, no data are available on this fauna, except for some morphological studies on Tunisian samples. In this study, 16 allozymic loci were used to investigate the phylogenetic relationships within Tunisian mugilids. The results obtained from Hergla lagoon samples highlight ¢ve operational taxonomic unit corresponding to the well-known species (Liza aurata, Liza ramada, Liza saliens, Chelon labrosus, Mugil cephalus). Several loci appeared to be diagnostic of these species, but in contrast to Greek mugilid samples, we did not ¢nd any diagnostic locus ¢xed di¡erently for the ¢ve species. These results can help aquaculture units to identify accurately the mullet species they subsequently use for stocking aquaculture ponds and inland waters. However, species identity represents very important information, as each species has a di¡erent growth rate and salinity tolerance. On the other hand, when compared with North Mediterranean Mugilidae analysed until now, Tunisian samples show a genetic di¡erentiation that could be related to di¡erent physicochemical conditions between the North and South banks, similar to those recorded in the eastern and western two Mediterranean basins separated by the Siculo-Tunisian strait. In addition, this study con¢rms the morphological taxonomy, except for the subdivision of the Liza genus into two sub-genera. The phylogenetic tree is in agreement with that on Languedoc Mugilidae samples (France), indicating that the subdivision of the Liza genus into two sub-genera appears to be without any genetic base.