engleski

Anchovy (Engraulis encrasicolus, L.) stock assessment in the Adriatic Sea: 1975-2003

Anchovy (Engraulis encrasicolus, L.) is one of the most important commercial species of the Adriatic Sea. Stock of anchovy, living in the northern and central Adriatic Sea and 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), with pooled data coming 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 1975-2003. 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 present stock assessment. Annual values of mid-year stock biomass at sea and annual values of the unweighted mean fishing mortality rate over the age class range 0-3 were obtained. In addition, on the basis of the fishing mortality rates and natural mortality rate mentioned, 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 was estimated in 1987, when a strong drop in the catch and crisis of the anchovy fishery took place. 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 to have risen to the values observed before the collapse, it would be unwise for fishing effort to be allowed to increase.

Adriatic Sea; Catch statistics; Engraulis encrasicolus; MED; Population dynamics; Shared stocks; Stock assesment

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