The importance of thermoperiod for proper gametogenesis and successful egg and sperm production in meagre (Argyrosomus regius) breeders in aquaculture

We examined the effect of constant water temperature throughout the year on gametogenesis, spawning success and egg/ sperm/embryo quality in meagre (Argyrosomus regius). Two broodstocks were exposed to simulated natural photoperiod, and either attenuated seasonal water temperature (SeasT, 16.4 to 19.6ºC) or relatively constant water temperature (CoT, 19.4 ± 0.6ºC). In the spawning period (May), 4 couples per group were induced to spawn with gonadotropin releasing hormone agonist (GnRHa). Gonadal stage of development, sperm quality parameters and plasma levels of sex steroids were evaluated prior to the GnRHa treatment. Spawning success and egg/sperm quality were examined over the following 4 weeks.