Co-Authors:
Milstein, A., Agriculture Research Organization, Fish and Aquacult. Res. Station Dor, M.P. Hof HaCarmel, 30820, Israel
Eran, Y., Fish and Aquacult. Res. Station Dor, M.P. Hof HaCarmel, 30820, Israel
Nitzan, E., Atlit Marine Fish Hatchery, Israel Salt Co. Ltd., P.O. Box 7, Atlit, Israel
Zoran, M., Agriculture Research Organization, Fish and Aquacult. Res. Station Dor, M.P. Hof HaCarmel, 30820, Israel
Joseph, D., Fish and Aquacult. Res. Station Dor, M.P. Hof HaCarmel, 30820, Israel
Abstract:
Tilapia wild spawning is a nuisance in warm freshwater aquaculture growout ponds. To cope with this problem two experiments were carried out with predatory fish that do not reproduce in fresh water. One experiment tested the capacity of hybrid bass (Morone saxatilis x M. chrysops) and red-drum (Sciaenops ocellatus) as predators of wild spawning of hybrid tilapia (Oreochromis niloticus x O.aureus), and the other compared predation effectiveness of red-drum of different sizes and stocking densities. Both hybrid bass and red-drum effectively reduced tilapia wild spawning and improved by 15-20% tilapia performance and food conversion ratio. These effects were obtained stocking small red-drum (20 g) or large red-drum (60-80 g) or bass (135 g) at stocking densities of 500-1000 predators/ha, together with 15000 tilapia/ha of 65-75 g. Hybrid bass stocked at 750/ha and large red-drum stocked at 500/ha presented over 90% survival. Red-drum at higher stocking density and/or lower stocking weight presented reduced survival (40-60%). Red-drum at all examined stocking weights presented better growth rates when stocked at 500/ha than at higher densities.