ABSTRACT
This experiment was conducted to investigate the effect of size of brood stock on egg fertilization,
hatchability and fry survival rate of Clarias gariepinus in an intensive culture system, for a period of
four weeks. Larger brood stock size (1200-1500g) produced larger eggs and bigger fry while
moderate brood stock size (795-1000)g produced moderate eggs and moderate fry. The mean size
of eggs produced and the size of brood stock was however not significantly different (p > 0.05). In
addition, larger eggs resulted in larger fry. The survival rate of fry after starvation increased with
increase in parent brood stock size. Best on this study it was recommended that for larger eggs and
fry production, brood stock of Clarias gariepinus, of average size of (1200-1500g) should be
selected for use in fish hatchery operation in Nigeria. There was no significant difference (p> 0.05)
in the physiochemical parameters.