Stocking density effects on survival, growth performance, feed utilization, and carcass composition of meagre, Argyrosomus regius (Asso, 1801) fingerlings reared in fiberglass tanks using underground saltwater

Four stocking densities (50, 100, 150, and 200 fish m-3) of meagre (Argyrosomus regius) fingerlings with an initial weight of 2.47 g were tested. Fish were stocked in fiberglass tanks and fed on a 47/17 protein/lipids ratio pelleted diet for 60 days. The survival rate, growth, feed utilization, and carcass composition were evaluated. Results indicated that predatory behavior increased with increasing fish density leading to a decrease in meagre's survival rate. Growth performance indices decreased with increasing fish density without significant (p > 0.05) differences between density 50 and 100 fish m-3. At lower stocking density, fish exhibited lower content of moisture and higher content of protein. A significant difference in the content of protein and lipids between density 200 fish m-3 and the other densities was recorded. Also, feed utilization indices (feed conversion ratio (FCR), productive protein value (PPV), %, and protein efficiency ratio (PER)) showed better values for lower densities and significant differences between density 200 fish m-3 and the other densities. From the results mentioned above, it could be concluded that the best stocking density of meagre is 50-100 fish m-3 using a wellbalanced artificial diet.