Sea bass (Lates calcarifer Bloch) reproduction in captivity: a research update

Recent advaces in the spontaneous and hormoneinduced breeding of caged sea bass (Lates calcarifer bloch, Family Centropomidae) are reviewed. Spontaneous spawnings follow a semilunar rhythm, with most spawings accurring in the evening of quarter moon. Independent of the Lunar-associatd rhythm, mature sea bass which have attained the critical oocyte size of 0.40 mm spawns after an injecton or implantation of luteinizing hormone-releasing hormone analogue (LHRHa) Pelleted LHRHa along together with methyltestosterone can advance sexual maturation and spawning in April-May, ahead of peak breeding in July-August. Depending on the pelleted or injected LHRHa dose, mature female sea bass spawns singly or consecutively over 4 evenings. LLHRHa-induced egg release peaks during the first day of a multiple spawning bout. Daytime injection of LHRHa stimulates spawning in the evening until dawn, while fish injected LHRHa at night induces spawning at daytime and releases fewer eggs compared to nighttime spawning. these results optimize the use of LHRHa to stimulate gonad maturation and spawning so that sea bass seed are made available for hatchery rearing and grow-out.