Untitled - CNR

Marine research at CNR12°13°14°15°16°17°12°13°14°15°16°17°46° 46°46° 46°45° 45°45° 45°44° 44°44° 44°43° 43°43° 43°12°13°14°15°16°17°12°13°14°15°16°17°12°13°14°15°16°17°46° 46°45° 45°44° 44°43° 43°Biomass = 00000=densityLow biomassdensityMedium biomassdensityHigh biomassdensity12°13°14°15°16°17°Figure 4: Maps of the spatial distribution of anchovy, sardine and sprat in north westernAdriatic Sea (September 2006).values through the Fish Bladder ResonanceModel [16] and acoustic data relative to thewater column stratum of the catch.3 Results3.1 Trends of anchovy, sardineand sprat biomass in thewestern side of the AdriaticSeaThe main outcome of the present researchis the evident variability in time of pelagicresources both considering the species as awhole and considering species separately.Pelagic community of the Adriatic Seais dominated by anchovies and sardinesthat constitute almost 80% of total pelagicbiomass.The trend of total pelagic biomass, derivedfrom echosurveys in the time interval 1976-2009, is shown in Figure 2. The graph indicatesthat the total pelagic biomass fluctuatesin a way which is almost periodical.The highest peaks around 134 t·nm −2and 104 t·nm −2 , were observed in 1983and 2008, respectively. In recent years thebiomass after decreasing below the meanincreased again.The trend of anchovy, sardine and spratbiomass in the Northern Adriatic Sea from1976 to 2009 is shown in Figure 2. Anchovystock has reached a peak in 1978,2023