Cultivation of the Mediterranean amberjack, Seriola dumerili (Risso, 1810), in submerged cages in the Western Mediterranean Sea

Abstract

The growth rate, survival and food conversion ratio (FCR) of the Mediterranean amberjack (Seriola dumerili, Risso, 1810) was ascertained in cultivation using submerged net cages in the Gulf of Castellammare (NW Sicily), from September to December 1994. Two net cages (volume = 75 m3) were placed at a depth of 10 m in a sheltered area 1000 m off the coast. Juveniles (mean total length = 141.4 ± 34 2 mm; mean total wet weight = 48 ± 28.1 g) were caught in the gulf under floating wreckage with a purse seine and transplanted to the cages (n = 800 per cage) in August. Fish in one cage, group A, were fed with fish scraps whilst fish in group B were fed with pellets The total length and body wet weight were recorded each month and compared with the wild population of the gulf. Negligible mortality occurred due to capture and transportation to the cages and no diseases were found during the rearing period. Group A reached a final size of 438.1 ± 25.3 mm and 1149 ± 172.2 g, while group B reached 347 ± 25.6 mm and 576 ± 139 g. At this time the wild population was 404.13 ± 17 mm and 777 ± 89.4 g. Food conversion ratios of 1.22 for group A and 3.51 for group B were in the low range compared with other research on S. dumerili in the Mediterranean. S. dumerili seemed to find fish scraps more appetising than pellets. The low level of investment required, limited breeding period and compatibility with small-scale fishing make submerged net cages a promising system of cultivation for the conversion of coastal fishing.