Decline in Fertilization and Hatching Rates of African Catfish Clarias gariepinus after Ovulation

摘要

This study observed the fertilization and hatching rates of African catfish Clarias gariepinus eggs stripped at different times after ovulation in three females (0.8-1,3 kg). Ovulation was induced by Ovaprim (20μg salmon gonadotropin releasing hormone analogue and 10 mg domperidone per ml) with a single dose of 0.5 ml/kg. Ovulation occurred between 8-9 h after the hormone treatment at 26.3-29.1°C. The fertilization and hatching rates decreased with time after ovulation (AO) at 26.7-28.9°C. The mean fertilization rates were 92.1% at 0 h AO and 47.4% at 6 h AO. The mean hatching rate was 81.4% at 0 h AO; this finally decreased to 0% at 6-8 h AO. This study concludes that C. gariepinus eggs should be stripped and fertilized within 3 h AO in order toachieve good quality eggs (more than 50% hatching rate on average).