Optimal combination of temperature and photoperiod for sex steroid hormone secretion and egg development of Oreochromis niloticus as determined by response surface methodology.

For successful reproduction of farmed fish, it is important to understand the relationship between gonadal development and environmental factors such as temperature and photoperiod. In this study, we determined the effects of temperature (T) and photoperiod (Pp) on serum estradiol-17β (E) and progesterone (P) contents, gonadosomatic index (GSI), and oocyte development in female tilapia. We used a central composite experimental design and response surface methodology.