Growout production of camouflage grouper, Epinephelus polyphekadion (Bleeker), in a tank culture system |
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| Authors: | C M James S A Al-Thobaiti B M Rasem M H Carlos |
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| Institution: | Fish Farming Centre, Ministry of Agriculture and Water, Under Secretariat for Fisheries Affairs, P.O. Box 9612, Jeddah 21423, Kingdom of Saudi Arabia |
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| Abstract: | Growout production of the camouflage grouper, Epinephelus polyphekadion (Bleeker), in a 10-m3-capacity fibreglass tank culture system was evaluated, using hatchery-produced fingerlings (56-59 g initial weight) at stocking densities of five, 15 and 45 fish m?3. During the first 9 months of a 12-month growout period, the fish were fed twice a day with a moist pellet feed containing 40.9% protein. From month 10 onwards until harvest, the fish were fed moist pellets in the morning and trash fish in the evening at a 1:1 ratio. The final weight of fish at harvest was up to 900 g, with mean weights of 544.6 ± 170.72 g at five fish m?3, 540.2 ± 150.82 g at 15 fish m-?3 and 513.3 ± 134.52 g at 45 fish m?3. The results showed no significant differences (P > 0.05) in growth rate and fish size between the different stocking densities tested. The average daily growth rate ranged from 0.62 to 3.38 g fish?1 day?1, with mean weights of 1.49 ± 0.74 g fish?1 day?1 at five fish m?3 through 0.53 to 2.38 g fish?1 day?1, 1.32 ± 0.57 g fish?1 day?1 at 15 fish m?3 to 0.48-3.32 g fish?1 day?1 and 1.31 g fish?1 day?1 at 45 fish m?3 stocking density. Although up to 100% survival was observed at the lowest stocking density, the survival rate significantly decreased (P < 0.05) with increasing stocking density. The food conversion ratio (FCR) significantly decreased (P <0.05) with increasing stocking densities, showing efficient feed utilization with increasing stocking densities of E. polyphekadion. The FCR averaged 2.1 at a stocking density of 45 fish m?3. The yield in terms of kg fish produced m?3 of water used in the culture system significantly increased (P < 0.001) from five to 45 fish m?3. The yield averaged 17.3 ±0.53 kg m?3 at a stocking density of 45 fish m?3. The present results show that the present tank culture system could sustain more biomass in terms of increasing fish stocking densities. The growth performance of E. polyphekadion observed during this investigation has been reviewed with other grouper species. |
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