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Abstract
This work was conducted in Faculty of Veterinary
Medicine, Physiology department, where it spotted on the
effect of some environmental and physiological factors such as
temperature, photoperiod and pheromones in regu lating
gonadal development in both sexes. The study was conducted
on 260 fish of Tilapia nilotica during the period from March to
July. The fish were divided into 3 groups, where 80 fish for
each temperature & photoperiod experiment and 1000 for the
pheromone experiment. Male & female parameter such as GSI,
sperm count, motility, fecundity’, oocyte maturation were
measured. Moreover, sex steroid hormones E2 & T and
calcium level in both sexes. Result showed that temperature of
27 & 30 after 20 days has beneficial effect on the maturity of
both sexes, modulation of photoperiod regimes. were non-
significant, and rearing males with females in the same
aquarium .