•In the seventies, considerable emphasis was given to the study of gonadal maturation and to the use of human chorionic gonadotropin (HCG) to induce spawning in the two species.
•The risks linked to excessive hormonal dosages on broodstock, which would affect later larval survival and viability, were clearly understood. The use of hormones acting at an early stage of ovarian maturation (such as the LH-releasing hormones) was also studied.