Influence of Stocking Density and Background Colour on the Growth Performance and Survival of Nile Tilapia Fry (Oreochromis niloticus).
A 70 day experiment was conducted at Moi University, Chepkoilel campus, Biological Science Department hatchery to investigate the effects of stocking density and background colour on the growth performance of Nile tilapia (Oreochromis niloticus) fry in glass tanks. Oreochromis niloticus fry (0.32 ± 0.02g) were reared in blue, black and clear tank backgrounds at two stocking densities of 2 fish l-1 and 4 fish l -1. The best growth performance (weight gain, specific growth rate, and food conversion ratio) was achieved under 2 fish l-1 stocking density and the blue background. Percentage survival of the fish was not affected by the stocking density but was significantly (p<0.05) affected by the tank background colour with fish reared in blue background showing the highest percent survival. Water quality parameters were not affected by the treatments except for total ammonium-nitrogen (TAN) which was significantly higher (p<0.05) at 2 fish l-1 stocking density. Nevertheless, all the water quality parameters were within the recommended ranges for O. niloticus culture. Increased aggression was observed under high density or when the fish were reared in clear backgrounds and black background gave the lowest growth performance (p<0.05). The results from the present study clearly suggests that O. niloticus fry should be reared at 2 fish l-1 in semi intensive tank culture systems in blue backgrounds and the use of black tanks should be avoided in O. niloticus larviculture.
| Main Author: | |
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| Format: | Thesis/Dissertation biblioteca |
| Language: | English |
| Published: |
Moi University
2010
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| Subjects: | Stocking density, Freshwater fish, Fish culture, Growth rate, |
| Online Access: | http://hdl.handle.net/1834/7227 |
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| Summary: | A 70 day experiment was conducted at Moi University, Chepkoilel campus,
Biological Science Department hatchery to investigate the effects of stocking density
and background colour on the growth performance of Nile tilapia (Oreochromis
niloticus) fry in glass tanks. Oreochromis niloticus fry (0.32 ± 0.02g) were reared in
blue, black and clear tank backgrounds at two stocking densities of 2 fish l-1 and 4 fish
l
-1. The best growth performance (weight gain, specific growth rate, and food
conversion ratio) was achieved under 2 fish l-1 stocking density and the blue
background. Percentage survival of the fish was not affected by the stocking density
but was significantly (p<0.05) affected by the tank background colour with fish reared
in blue background showing the highest percent survival. Water quality parameters
were not affected by the treatments except for total ammonium-nitrogen (TAN) which
was significantly higher (p<0.05) at 2 fish l-1 stocking density. Nevertheless, all the
water quality parameters were within the recommended ranges for O. niloticus
culture. Increased aggression was observed under high density or when the fish were
reared in clear backgrounds and black background gave the lowest growth
performance (p<0.05). The results from the present study clearly suggests that O.
niloticus fry should be reared at 2 fish l-1 in semi intensive tank culture systems in
blue backgrounds and the use of black tanks should be avoided in O. niloticus
larviculture. |
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