Outdoor larval rearing of golden rabbitfish (Siganus guttatus): Observation on embryogenesis and early development stage

Abstract

The outdoor culture system is an extensive larval rearing system used to produce fingerlings using a large volume of facilities in outdoor conditions. This study was aimed at investigating the embryogenesis and early-stage development of larval golden rabbitfish reared in outdoor concrete tanks. Selected broodstocks were spawned in a tank equipped with a substrate for egg attachment. The larvae were reared in a 64 m3 concrete tank with sand substrate at the bottom, at a density of 5 individuals per liter for 25 days. The larvae were fed with rotifers and commercial powder feed during the experimental rearing. The results showed that female broodstock weighing 712 – 755 g had a fecundity of 413,400 – 585,000 eggs. Embryo development from the 2-cell stage to hatching took 20 hours and 10 minutes. The hatching rate was 44 – 66% at an egg diameter of 450 – 661 µm. D-1 larvae had a total length of 2.4 mm, and mouth opening occurred at late D-2. At the end of the experimental period, larval growth achieved a total length of 21.0 mm.