EFFECT OF WATER SALINITY ON THE REPRODUCTIVE AND GROWTH PERFROMANCES AS WELL AS PROLACTINAND GROWTH HORMONE LEVELS OF NILE TILAPIA, OREOCHROMIS NILOTICUS

EFFECT OF WATER SALINITY ON THE REPRODUCTIVE AND
GROWTH PERFROMANCES AS WELL AS PROLACTINAND GROWTH
HORMONE LEVELS OF NILE TILAPIA, OREOCHROMIS NILOTICUS
BY
ABDALLA, A. EL-SHEBLY*
*National Institute o[Oceanography and Fisheries
ABSTRACT
The present work was un~ertaken to study the effect of different
salinities on the reproductive and growth performances as well as
prolactin (pRL) and growth hormone (GH) levels of Nile tilapia,
Oreochromis niloticZls. The results showed that:At eqUivalent salinity,
early exposure (spcnvning) produced progeny of comparatively higher
salinity tolerance than those spcnvned in freshwater and hatched at
elevated salinity;Hatching success and fry production were greater in
Oreochromis niloticus broodfish spawned at 5 ppt than in freshwater, 10
and 15 ppt;The growth performance ofOreochromis niloticus fingerlings
was decreased with increasing water salinity;PRL and GH levels in blood
were higher in freshwater fishes than those reared in brackish water,
thereby the condition factor (K)
decreased with increasing salinities.
of the reared fish fingerlings was