Effect of different
schedules for broodstock exchange on the seed production of Nile tilapia Oreochromis
niloticus (L.) in freshwater
M.T. Ridha, E.M. Cruz-2003
Aquaculture
International, 11(3):
267-276
Abstract:
This study compares the effect of three broodstock
exchange treatments (exchange every month, two months and three months)
versus no-exchange control treatment on year-round seed production and
spawning synchrony of Nile tilapia Oreochromis niloticus stocked in
0.4 m3 fiberglass tanks within a recirculating water system.
Adult males and females with mean body weights of 161.7 g and 127.6 g,
respectively, were stocked at a rate of 4 fish/tank with a male to female
sex ratio of 1:3. Water temperature at 29 ±
1.0 °C and photoperiod of 18 h/day were
maintained throughout the experiment. The results showed that broodstock in
the exchange treatments had higher seed production and spawning synchrony
compared with those in the no-exchange treatment. The exchange treatments
resulted in 70.5 to 97% increase in seeds kg female-1 day-1.
The different spawning parameters of broodstock in the two- and three-month
exchange treatments were higher than the one-month exchange treatment.
Results suggest that broodstock exchange strategy has a long-term
improvement effect on seed production and spawning synchrony, and exchanging
all breeders every three months is more profitable in terms of better
utilization of breeders and in reducing both the holding/conditioning
facilities for broodstock and the labor cost.
(Aquaculture,
Fisheries and Marine Environmental Department, Kuwait Institute for
Scientific Research, Salmiyah, 22017, Kuwait, e-mail: mridha@kisr.edu.kw)