Distribution and numerical taxonomy of Vibrionaceae in the waters of the Straits of Messina.

The results of a study carried out by numerical analysis on Vibrio strains isolated from the waters of the Straits of Messina are reported. The quantitative data showed the presence of low bacterial densities (ranging from 9 to 99 CFU/100 ml of water) due to the intense currents which characterize this area; also the highest bacterial counts were generally found during the "montante" current. With regard to the qualitative results, there was a predominance of vibrios belonging to V. mediterranei, V. splendidus II and V. pelagius II species, which represented respectively 25%, 19% and 13% of the total bacterial population. The species distribution did not seem related to sampling stations or depth. The taxonomic structure, obtained using the simple matching coefficient and unweighted average linkage clustering, revealed the presence of 7 main clusters (S = 80-95%), which included strains of various origin because of the particular turbulence of the waters of the Straits.