Effect of stocking density and tank colour on nursery growth performance, cannibalism and survival of the Asian seabass Lates calcarifer (Bloch, 1790) in a recirculating aquaculture system

Cannibalism is one of the major issues causing mortality in the Asian seabass Lates calcarifer nursery phase. The present study aimed to investigate the effects of stocking density and background colour of rearing tanks on the growth performance, cannibalism and the survival of the Asian seabass fry in a recirculating aquaculture system (RAS). The Asian seabass fry was reared in white and black tanks at three stocking densities of 0.5, 1.0 and 1.5 individuals/L for 45 days. The initial body weight of the Asian seabass fry was 0.25 ± 0.00 g, and the total body length was 2.50 ± 0.00 cm. The weight gain, specific growth rate and fish survival were negatively correlated with stocking density, whereas overall yield was higher in higher stocking density. White colour tanks achieved better growth performance (weight gain, specific growth rate, yield, mortality and survival) than black tanks achieved except for cannibalism. There were significant interaction effects between stocking density and tank colour on weight gain, specific growth rate, feed conversion ratio, yield, the type-1 cannibalism, mortality and survival. The study concludes that the Asian seabass fry reared at a stocking density of 0.5 individual/L grows better than the stocking density of 1.0 and 1.5 individuals/L in the RAS and black tanks should be avoided for nursery rearing.