Effects of types and quantity of live food on growth performance and survival rate of cobia larvae (Rachycentron canadum)

Abstract

The objective of the study was to evaluate effects of 3 different diets and 3 different live food stocking densities on cobia fingerling rearing in composite tanks system in the Ninh Thuan 1st grade Seafood Breeding Center from 6 - 25 days old. The experiment was performed as a 3 × 3 factorial design [live food types: 100% Copepoda (Cop), 100% Nauplius of Artemia (Art), and 50% Copepoda + 50% Artemia; live food stocking densities: 5 - 10 individuals/mL, 10 - 15 individuals/mL, and 15 - 20 individuals/mL]. Each treatment had 5 replicates. After the nursery phase, the results showed that environmental parameters in all treatments were in normal ranges for cobia larvae growth. There was no difference in total length when cobia larvae were fed different feed densities (P < 0.05). The 100% Art live food and the live food density of 15 - 20 individuals/mL gave the highest growth rate, whereas the 100% Cop live food and the live food density of 5 - 10 individuals/mL resulted in the lowest weight of larvae. There was no difference in weight gain when simultaneously changing the types and live food density (P < 0.05). The survival rate of cobia larvae was highest for the 100% Cop live food and the live food density of 15 - 20 individuals/mL and lowest for the 100% Art live food and the live food density of 5 - 10 individuals/mL. However, there was no difference in the survival rate of cobia larvae when simultaneously changing the types and live food density (P < 0.05).