Untitled - CNR

Fishery and Sea ResourcesMid-Line200 mFigure 1: Study area of the acoustic survey performed by CNR ISMAR of Ancona in theAdriatic Sea. On the left north western Adriatic Sea, on the right south western AdriaticSea.changes in the abundance, composition anddistribution [11, 1, 12]. The historical surveysseries in the Northern Adriatic Seathat is the most important area in terms ofpelagic fish biomass levels, started in 1976,while in the southern Adriatic Sea it startedin 1987.In this paper temporal fluctuations of anchovy,sardine and sprat biomass in thenorth-western Adriatic Sea derived fromacoustic surveys conducted in 1976-2009were reported. The main results arethe large temporal changes of the pelagicbiomass as a whole and per species and thespatial distribution pattern of the pelagicbiomass over the years. The sampling limiteastward is constituted by the Mid-Line.This didn’t allow to assess all the stock unitof the small pelagic species that is shared inthe Adriatic Sea, however this is the mainpart exploited by the Italian fishery.Moreover the preliminary results are reportedof recent specific acoustic surveysconducted in this area in order to study thegeographic distribution and the abundanceof juveniles of small pelagic fish (sardineand anchovy) and improve the knowledgeof the acoustic properties of late-larvaestages.2 Materials and MethodsIn 1976, the Marine Acoustics Unit of Ancona’sCNR ISMAR started to carry outoceanographic surveys in the western sideof the Adriatic Sea for the evaluation ofsmall pelagic fish biomass by means ofacoustic methodology (Figure 1). The areascovered by the surveys were on averagerespectively 7705 nm 2 in the north AdriaticSea and 6493 nm 2 in the south AdriaticSea, from Italian coast to Mid-line/200m bathymetry. These surveys were carriedout annually, in the warm season.The biomass assessment and its spatialdistribution for all the pelagic species to-2020