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UPV Theses and Dissertations

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AGROVOC Keyword: search.filters.agrovoc.pondsScientific name: search.filters.scientificname.Chanos chanos

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    A comparative study of the effects of supplementary feeding and artificial substrate on the production of milkfish fingerlings in brackishwater ponds
    Adeyemi, Frederick F. (University of the Philippines Visayas, 1983-03)
    The growth and survival of milkfish fry in response to supplementary feeding and artificial substrate were evaluated at stocking densities of 75 and 100 fry/m2 for a period of 56 days from August 21 to October 15, 1982. The study was conducted in eighteen 40m2 experimental nursery ponds of the University of the Philippines Brackishwater Aquaculture Centre, Leganes, Iloilo. A 3 x 2 factorial experiment in completely randomized design was used and six treatment combinations between level of inputs (no inputs, supplementary feeding or artificial substrate) and stocking density (75 or 100 fry/m2) were investigated with three replicates per treatment. The best fish growth was obtained in Treatment VI (100 fry/m2 with substrate) with mean final weight and length of 1.59 gm. and 5.36 cm. respectively while Treatment IV (100 fry/m2 without feeding or substrate) gave the poorest fish growth with mean final weight and length of 0.83 gm. and 4.60 cm. respectively. Differences in mean weight and length among treatments were, however, not statistically significant. Mean percentage survival was significantly higher at a stocking density of 75 fry/m2 (82.8%) than at 100 fry/m2 (64.1%) but supplementary feeding or artificial substrate ix did not show any statistically significant effect on survival. At either 75 or 100 fry/m2 stocking density, supplementary feeding gave a numerically higher percentage survival than artificial substrate. Economic analysis revealed that a stocking density of 75 fry/m2 without supplementary feeding or artificial substrate was the most profitable treatment with a return on investment of 39.2%. At a stocking density of 100 fry/ m2, supplementary feeding with rice bran was more profitable than the use of artificial substrate with returns on investment of 22.6% and 9.1% respectively.
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    Effect of cow and chicken manures on milkfish Chanos chanos (Forsskal) production in brackishwater ponds
    Aduma, Ignatius A. (College of Fisheries, University of the Philippines in the Visayas, 1984-05)
    A study using chicken and cow manures with basal application rates of 0.5 , 1,2 and 4 tons/ha was conducted. The effect of both manures on some selected physico­-chemical properties of the pond soil and water, primary productivity, and milkfish Chanos chanos (Forsskal) yield were compared. Using 8 treatments with 3 replicates each in a completely randomized design, 24 units of 40 m2 ponds were stocked with 20 fingerlings/pond. The fish were cultured from September 22 to December 20, 1983 at the Brackishwater Aquaculture Center of the University of the Philippines in the Visayas College of Fisheries, Leganes, Iloilo, Philippines. The differences among treatments in terms of all physico-chemical parameters monitored were not significant except for the reactive phosphorus. Primary productivity in all treatments was at its peak during the 5th week, after which, it declined gradually apparently due to the combined effects of cloudy weather and low concentration of reactive phosphorus in the pond water. The highest mean net fish yield (680.9 kg/ha) and mean growth rate (1,54 g/day) were obtained in treatment 3 with 1 ton/ha of chicken manure. Treatment 2 (0*5 ton/ha of cow manure) had the lowest mean net fish yield (343.6 kg/ha) and likewise the lowest growth rate (0.80 g/day). The survival in all treatments was high, ranging from 95 to 100%. In general, chicken manure was superior to cow manure, however, fish production from the treatment with 2 tons/ha of cow manure was comparable to that of 2 tons/ha of chicken manure suggesting that cow manure could be used as organic fertilizer in brackish- water ponds for milkfish production.