ACCELERATION OF GONADAL DEVELOPMENT AND SPAWNING INDUCTION IN THE MEDITERRANEAN GREY MULLET, MUGIL CEPHALUS - PRELIMINARY STUDIES

Grey mullet broodstock, maintained under a shifted photoperiod, were t reated with controlled-release hormonal devices to accelerate gonadal development and subsequent spawning. The females received testosterone and a superactive GnRH analogue (GnRHa) given via slow-release device s (microspheres). The males received 17 alpha-methyltestosterone via m icrospheres. Once oocytes reached the diameter of >500 mu m, females w ere induced to spawn with GtH-calibrated carp pituitary extract follow ed 24 hours later by GnRHa administered via a sustained-release implan t. The females were allowed to spawn in the presence of males. An aver age of 4.4 million eggs was obtained from each female, and the fertili zation rate ranged from 20% to 98%.