Feeding frequency for dusky grouper Epinephelus marginatus juveniles with automatic feeding system

Salt-water recirculation systems using automatic feeders are a new frontier for marine aquaculture. The definition of the feed frequency is fundamental for the correct use of automatic feeders. Different feeding frequencies (1, 3, 6, 12 and 18 times a day) using automatic feeders were evaluated in two experiments on the performance of the dusky grouper (Epinephelus marginatus) in salt-water recirculation system. In the first experiment, three feeding frequencies were evaluated: feeding once a day; three times a day and six times a day. In the second experiment, three feeding frequencies were evaluated: feeding six times a day; 12 times a day and 18 times a day. Waters parameters (temperature, salinity, oxygen level, total ammonia, pH and oxidation-reduction potential) were maintained at specific ranges for the species. Among all the evaluated frequencies, 12 times a day provided the best productive performance, obtaining superior results for final weight, final biomass, specific growth rate and daily weight gain. For juveniles of the dusky grouper, the ideal feeding frequency is regular feedings every 2 hours, which is impractical to run without the use of automatic feeders.