Effects of photoperiod on growth performance, survival and stress resistance of juvenile giant trevally (Caranx ignobilis)

Abstract

This study was carried out to evaluate the effects of different photoperiod on the growth performance, survival rate, and stress resistance of juvenile giant travelley. Fish were fed four times a day (at 7:00; 10:30; 14:00 and 17:30). The experiment was designed with three different photoperiods:  12 hours, 18 hours, 24 hours, and the control treatment—natural photoperiod with three triplicated. A total of 1680 fish were randomly distributed among composite tank of 100 liters (70 liters of water volume). After 28 days, fish samples were collected to analyze survival rate, growth performance, heteromorphic ratio, FCR, and stress resistance. Results indicated that final weight and specific growth rate were significantly influenced by the photoperiod. Juvenile giant travelly exhibited the highest growth under the natural photoperiod, with the final length and weight of 63,25 ± 1,85 cm/fish and 3,51± 0,01 g/fish, respectively, that was not diffence with 12h but differing significantly from the 18 hours and 24 hours of treatment. The highest survival rate in the 24-hour treatment (96,07%), and the lowest survival in the control treatment (85%) and have statistically significant differences. The worst resistance shock was in the 24-hour treatment after 30 minutes of temperature and 10 minutes of sanility. Thus, the optimum photoperiod for juvenile giant trevally rearing could be a 12 hours of photoperiods