Effect of different stocking densities and feeding on the growth of Oreochromis niloticus (L.) in floating cages in Sampaloc Lake, Laguna, Philippines
1991
Suyatna, I.
A field study was conducted in Sampaloc Lake, San Pablo City, Laguna [Philippines] from June to September 1990. The objective was to determine the growth of Nile tilapia (Oreochromis niloticus) by cage culture, under different stocking densities and supplemental feeding. Three stocking densities of 50, 75, and 100 fish/cu.m. were tried and the feeding levels included fine rice bran and mixed feed (50% fine rice bran and 50% commercial feed), and a control without feeding. The observation on physico-chemical and biological parameters in and outside the experiment fish cages showed that water temperature, pH values, and dissolved oxygen concentrations were well within the optimal limits for tilapia culture, but natural fish food organisms appeared to be poor. Study on the analysis of variance on feeding and stocking densities and their interactions on the growth of O. niloticus indicated significant differences. Also, mean weight gain sampled biweekly for various treatments showed that the treatments were significantly different. The results indicated that the control without feeding gave lowest growth at all stocking densities followed by fine rice bran and mixed feed, respectively. Of the three levels of stocking densities, the highest stocking rate gave maximum production while lower stocking densities resulted in better individual daily weight increment for treatments stocked at 50 pcs/cu.m. with no feeding (control) with feeding fine rice bran, and mixed feed was 0.13 g/day, 0.28 g/day and 0/72 g/day, respectively. The congestion of large number of commercial cages in the vicinity of the experimental site affected the growth efficiency of O. niloticus.
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