This is the first report on the characterization and virulence of V. parahaemolyticus for
sea bass in Tunisia and in Mediterranean coast. Vibriosis causes enormous economic
loss in Tunisian aquaculture. The present study indicates that high abundance of extracellular
hydrolytic enzyme profiles in the different strains isolated during this outbreak
can be a main reason for the high mortality caused by this species. Knowing that, most
of the fish larvae elevated in offshore farm are imported from several hatcheries in the
Mediterranean Sea countries (France, Spain and Italy), and the inshore farm has its
own hatchery. Moreover, genetic study is needed to view if strains responsible for such
mortalities are imported with these larvae and introduced into Tunisian environment
or they are already present in our environment (autochthon strains).