Rearing and spawning siganids (Pisces: Teleostei) in a closed seawater system

Abstract

1. Two species of signaids from The Philippines, Siganus oramin and S. concatenata (S. guttatus?), were reared in a closed sea water system and fed different artificial feeds. 2. A comparison between commercial chicken and rabbit feeds in regard to their suitability as siganid feeds led to the conclusion that for this purpose the latter was the more appropriate diet. 3. Within six months juvenile S. oramin (4-6 cm, 2-6 g) reached maturity and were treated with human chorionic hormone (HCG) in order to induce ovulation. 4. Two females were successfully stripped after having received HCG injections. The eggs were artificially inseminated and incubated at 15.8, 20.9, 30.6 and 32.2‰ S. 5. Early embryogenesis was evaluated by means of time lapse movie pictures (two frames/min). 6. Incubation of the eggs at 26°-28° C took 29 h from fertilization to hatching. Viable larvae hatched only between 20.9 and 32.2‰S and larval survival was best in 32.2‰S. There was no viable hatch at 15.8‰S, and no fertilization occured at 12.1‰S. © 1975 Biologischen Anstalt Helgoland.