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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2065

Title: THE EFFECT OF STOCKING DENSITY AND SUPPLEMENTARY FEEDING ON GROWTH PERFORMANCE AND YIELD OF NILE TILAPIA [OREOCHROMIS NILOTICUS (L, 1758)] IN CAGE CULTURE IN WONJI RESERVOIR, ETHIOPIA
Authors: Abdilahi, Dill
Advisors: Dr. Abebe Getahun
Prof. Krishen Rana
Keywords: Cage culture
Growth performance
Wonji Reservoir
Nile tilapia
Copyright: Jun-2010
Date Added: 2-May-2012
Publisher: AAU
Abstract: This research was conducted to investigate the effect of stocking density and supplementary feeding on growth performance and yield of Oreochromis niloticus in cage culture in Wonji Reservoir. The treatments had stocking densities of 25 (25F), 50 (50F), 75 (75F) with 3 supplementary feed and 25 (25N), 50 (50N), 75 (75N) fish per m cage without supplementary feed. The treatments with supplementary feed were in duplicates and the controls were single. Juveniles with average weight of 43.70 ± 0.19, 43.12 ± 0.5, 43.38 ± 1.14, 43.97 ± 0.36, 43.51 ± 0.33 and 43.98 ± 1.18 gm were stocked in 25F, 50F, 75F, 25N, 50N and 75N treatments, respectively. The fish were fed 3% of their body weight twice per day using feeding trays for 100 days. The results indicated that growth performance of O. niloticus was density dependent. The final mean weight of O. niloticus in 25F was 175.83±0.68 gm and the mean daily weight gain was 1.36 gm, whereas in treatments (50F, 75F) and controls (25N, 50N and 75N), final mean weight was 154.92±0.82, 146.70±0.15, 86.67±0.51, 73.64±0.26, 72.62±0.46 gm and mean daily weight gains were 1.06, 0.77, 0.55, 0.28 and 0.27 gm, respectively. Moreover, feed conversion and condition of fish were affected by stocking density and supplementary feeding. The apparent feed conversion ratio (1.45 – 4.45) was significantly affected by stocking density (P<0.05). Fulton condition factor was inversely affected by stocking density while it was directly affected by supplementary feeding. However, survival rate was not affected by stocking density and supplementary feeding (P > 0.05). In this experiment, it can be concluded that the 3 most effective stocking densities for O. niloticus cultured were at 25 fish / m cage for larger 3 size fish demand in short period and 75 fish/m for higher gross production with supplementary feed. Physical, chemical and biological parameters were the same among cages or between cages and the open water in the present experiment. Thus, all O. niloticus had similar culture environment and equal access to natural feeds.
URI: http://hdl.handle.net/123456789/2065
Appears in:Thesis - Biology

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