FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

This study investigated the efficacy of induced spawning in snubnose pompano, Trachinotus ovatus by injection of human chorionic gonadotropin (HCG) and salmon gonadotropin releasing hormone-analogue (sGnRH-A)+Domperidone (Dom) (Ovaprim). Four groups of snubnose pompano, 120~180 fish (2.8~7.6 kg) in each trial, were injected HCG and ovaprim with dosage of 1000~1600 IU/g BW and 0.3~0.5 cc/kg BW, respectively, during February and March. Spawning occurred at 10~16.5 h after hormonal treatment with 2~3 spawning days in each trial. Markedly difference in egg production ranged from several millions to several ten millions in every trial with viable eggs ranging from 55~75%. Eggs are spherical and buoyant with diameter of 1 mm. Most of fertilized eggs contain multiple oil globules. At water temperature of 24~24.5℃ and salinity of 35 ppt, fertilized eggs hatched at 32 h and 45 min after fertilization. The total length of newly-hatched larvae is 2.75 mm, and follow-up 3.63, 6.63, 9.46, 38.84 and 89.42 mm at 6, 14, 20, 40 and 80 days old, respectively. The fry is similar to the adult fish with the silver body color except the black dorsal fin at 26 days old. Optimum concentration of clove oil for anesthesia of snubnose pompano is 15 ppm. In this study, fertilized eggs of snubnose pompano can be steadily obtained by hormonal treatment of HCG and sGnRH-A+Domperidone.