Exotic and Invasive Fish Species off the Southern Coast of Sicily (Central Mediterranean Sea)

Paradoxically, almost all the marine life of the Mediterranean Sea is of exogenous Atlantic origin, because the old Tethys has been subject to repeated pan‑anoxic dystrophic events. Nowadays, the presence of allochthonous species is often attributed to a direct effect of global warming. Nevertheless, this hypothesis is not always true, and recent “colonizations” of exotic fish might be linked to other factors; by the way, apart from the fisheries effects, modifications on the respective proportions among indigenous fish species in the present assemblages could be more representative of climate changes. In the last few years, about 15 new fish species of different origin have joined the list of the ichthyological fauna of the Strait of Sicily (southern‑central Mediterranean Sea); unluckily, only one, the puffer fish Sphoeroides pachygaster, presents certain records and quantitative data. The puffer fish, practically absent from Sicilian waters until the end of the ‘80s, is now caught all over the shelf, with abundances of 1‑2 specimen/km²; given the occurrence of young animals too, its population seems self‑reproducing and probably established. In order to verify possible relationships between fish invasions and global climate changes at a meso‑scale level, besides the temporal evolution, more studies are required on the spatial development of these new entries, and greater collaboration among south European and northern African research institutions.