engleski

Anchovy (Engraulis encrasicolus, L.) stock assessment in the Adriatic Sea: 1975-2002

Anchovy (Engraulis encrasicolus, L.) is one of the most important commercial species of the Adriatic Sea. The stock of anchovy living in the northern and central Adriatic Sea is shared between Italy, Slovenia and Croatia. This assessment is relative to the anchovy stock of the northern and central Adriatic Sea (GFCM GSA 17), pooling together data from Italy, Slovenia and Croatia. It has been carried out in the context of the AdriaMed-SP research programme. The annual catch of anchovy for the three countries mentioned was obtained for the time interval 1975-2002. These quantities were distributed into fish age classes, so that catch-at-age data were available. That represented the basic input data of Virtual Population Analysis (VPA), employed for the stock assessment described herein. Annual values of mid-year stock biomass at sea, annual values of the unweighted mean fishing mortality rate over the age class range 0-3, annual values of mid-year spawning biomass and corresponding ratios between catch and mid-year spawning biomass were obtained. In addition, annual exploitation rates were calculated and compared with a threshold derived from literature and suggested for small pelagics. The minimum value of both catch and biomass at sea were estimated in 1987, when a substantial drop in the catch and crisis of the anchovy fishery occurred. Even if high values of both fishing effort and fishing mortality rate were obtained for some years before 1987, very low levels of recruitment in 1986 and 1987 seem to be mainly responsible for the collapse of the stock. Since current biomass seems not have risen to the values observed before collapse, it would be unwise for fishing effort to be allowed to rise. With regard to the south Adriatic (GFCM GSA 18), not enough catch and effort data and biological data are currently available for the anchovy to allow stock assessment to be performed. Data collection in the south Adriatic is being carried out in the context of AdriaMed-SP research programme together with the retrieval of past data. Therefore, in the near future, a joint stock assessment will be possible in this area too.

catch/effort - pelagic fisheries - population dynamics - shared stocks - stock assessment

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