UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Masters Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/12

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1995 - 199912000 - 20031

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Scientific name: search.filters.scientificname.Siganus guttatusSDG: search.filters.sdg.SDG 14 - Life below water

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    Tolerance and behavioral response of Juvenile Siganus guttatus to Abaca Pulp Mill effluent
    Bradecina, Raul G. (College of Fisheries and Ocean Sciences, University of the Philippines in the Visayas, 2003-04)
    Acute bioassay and avoidance-preference tests were done on juvenile S. guttatus using lethal and sublethal concentrations of Abaca pulp mill effluent to assess the fish tolerance and behavioral response to the toxic stress and determine its effect to the chemoreception of biologically important odors. Acute bioassay response data were analyzed by log-probit method. Behavioral response data were calculated from the mean reaction values of the fish samples in the Y-maze apparatus. Results show the fish has a very narrow resistance to the toxic stress of the effluent with LT50 values of 1.6 h for the highest (100% vv-1) and 37 h for the lowest (10%vv-1) concentrations. The 48 h LC50 was located at 9%vv-1 which indicated the fugacity of the effluent and the sensitivity of the fish to its toxicity. The lowest concentration of the effluent with observed significant effect (LOEC) was located at 10%. The fish showed pronounced and significant discriminating ability at lethal concentration of the effluent. Avoidance reactions of the fish were only observed at 9% vv-1 (lethal) and 0.9 % vv-1 (sublethal) concentrations. The avoidance threshold was found at 0.74 % vv-1. Juvenile S. guttatus has a very narrow acuity to the effluent, which was located at a tenth ofthe mean lethal concentration value. Abaca pulp mill did not mask chemoreception of biologically important odors in juvenile S. guttatus.
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    Growth and yield Rabbitfish (Siganus guttatus) reared in river floating net cages at various stocking densities and feeding schemes
    Abalos, Rosie S. (University of the Philippines Visayas, 1995-03)
    Six treatment combinations consisted of three stocking densities of 50, 100, 200, rabbitfish (Siganus guttatus) per cubic meter (m3) at two feeding schemes of sliding 10, 8, 6, 5% commercial feed of fish biomass (F1) and 5% commercial feed of fish biomass daily with Chaetomorpha linum. "lumut" fed to satiation (F2) were tested to determine the growth and yield of rabbitfish in river floating net cages for 120 days. The F1 at stocking density of 50 fish/m3 and fed commercial feeds daily at sliding (10-8-6-5% BW) feeding scheme registered the highest mean growth of 105.6 g/fish. However, statistical analysis showed no significant difference (P>0.05) in growth among treatments. In terms of production, the F2 at 200 fish/m3 and fed commercial feeds at 5% BW plus "lumut" registered the highest mean production of 18.23 kg/m3 . Production was highly significant (P<0.01) in between stocking densities but not between feeding schemes. Survival (90 - 96%) and mean feed conversion ratios (3.6 - 4.4) were not significantly different (P>0.05) among treatments. Rearing S. guttatus in floating net cage at 200 fish/m fed commercial feeds daily at 5% BW plus "lumut" fed to satiation appeared to give the highest net income of P705.96/m and a benefit-cost-ratio of 1.42.