Assessment of Small Pelagic Fish Biomass in the Western Adriatic Sea by Means of Acoustic Methodology

Since 1976, ISMAR CNR of Ancona has been conducting acoustic surveys in the north-western Adriatic Sea, with the aim to assess biomass of small pelagic fish, in particular anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and sprat (Sprattus sprattus). Since 1987, acoustic surveys were also conducted in the central and southern Adriatic Sea. The sampling limit eastward is constituted by the Mid-Line or the 200 m bathymetry in the southern part. These surveys are carried out annually, in the warm season (summer-early autumn). The main results are the large temporal changes of the pelagic biomass as a whole and per species and the spatial distribution pattern of the pelagic biomass over the years. In recent years specific acoustic surveys have been conducted in this area in order to study the geographic distribution and the abundance of juveniles of small pelagic fish (sardine and anchovy) and improve the knowledge of the acoustic properties of late-larvae stages.