Induced spawning of rabbitfish, Siganus guttatus (Bloch) using human chorionic gonadotropin (HCG)

Abstract

A positive spawning response of rabbitfish females to two injections of HCG at 2 I.U./g BW given 24 h apart was observed. The latency period after hormone injection was inversely related to the initial oocyte size. Minimum initial oocyte size required for spawning without hormone injection was 0.46 mm. HCG induction of spawning was necessary for females with initial oocyte size of ≤0.45 mm. Number of eggs spawned (424000), fertilization rate (96%), and hatching rate (59%) did not differ from those of naturally spawned fish.