engleski

Husbandry and Epizootiology in the Adriatic Cage Reared Bluefin Tuna (Thunnus thynnus)

Croatia has 5 tuna farms at eight locations dispersed between islands of central Adriatic Sea, being at the second place in the overall year production in the Mediterranean (4500 t). In contrast with other Mediterranean countries that developed the fattening process, Croatia employs markedly different technology with doubtful coast-benefit output. It involves the catch of smaller tuna specimens, which necessities longer confinement period in cages in order to obtain a proper market weight. Fish weighting 5-15 kg are caught near the Island of Jabuka, South Adriatic Sea, towed by purse seiners to the facilities and reared up to three years. Even this practice evokes serious concerns regarding its long-term sustainability from the stock management point of view, it made possible at some extent to plan and study this species in the rearing system, helping to enlighten some missing points in its biology and ecology. Long rearing cycle and employed technology however, made possible the emerging of different opportunistic diseases not known in short fattening cycle in the rest of Mediterranean. Usually seasonal bacterial infection or nutrients deficiencies are the main cause of early spring mortalities, while no viral diseases were so far detected. Rich and divers parasitofauna mainly has no implication in diseases outbreaks, showing decrease in communities during the rearing cycle.

Mediterranean; Adriatic Sea; bluefin tuna; diseases

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