Some observations on the growth of juvenile amerjack (Seriola dumerili, RISSO, 1810) in cage rearing from the southern Adriatic Sea

Abstract

       The growth rate of the few months old Mediterranean amberjack (Seriola dumerili) was stud­ied throughout a period of one year (from Sept ’95 to Sept ’96) in the Bay of Mali Ston (South Adriatic). Sixty nine fish with an average weight of 183±57.5 g and total length of 25.2±2.8 cm were settled in rearing cages (5x5x5 m) on September 27. 1995 for the purpose of studying growth in weight and length. The fish were usually fed frozen sardines once a day, every other day. The first month of rearing the fish showed considerable growth in weight (328±92.7 g) and length (28±2.5 cm). At the end of the one-year period, the reared fish averaged 1239±129.8 g in weight and 47.8±1.7 cm in length. The condition factor throughout the entire period of rearing was relatively homogenous, at 1.38±0.15. Significant gains in the weight and length of fish can be noticed during the warmer periods of the year (June, July, August, September and October), while less are for the colder months (January, February, March, April). The fish preferred frozen sardines. During this experiment, we noted the mortality of 7 fish (10.1%). Moreover, the sudden oscillations in the basic hydrographic parameters for this relatively enclosed bay can be attributed to the influence of the river Neretva.