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UPV Theses and Dissertations

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    Evaluation of feeding performance of early siganid, Siganus guttatus, larvae fed with mixed zooplankton
    Andrade, Maria Shiela S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-04)
    Siganus guttatus is an economically important rabbitfish for commercial farming. It is very important to evaluate their feeding performance particularly the effects of different diets for this larvae and to determine their growth and survival after being fed on different diets. Newly-hatched siganid, Siganus guttatus, larvae were reared in 500-L fiberglass tanks and fed either on copepod nauplii and rotifers alone or combination of both. Copepod nauplii proliferated in tanks consisted mainly of Pseudodiaptomus sp., and Acartia sp. Siganid larvae successfully commenced feeding (feeding incidence) on early stage copepod nauplii even if their abundance was low. Selective feeding ability of larvae seemed to start from day 6 and the larvae thereafter preferred to feed nauplii than rotifers. Survival of the siganid larvae was significantly higher when fed with with combination of rotifers and copepod nauplii compared to those fed with either rotifers or copepod alone. The growth of the larvae however are the same for all treatments. Results of this study suggest that coastal calanoid copepods of the genus Pseudodiaptomus sp. and Acartia sp. could be reproduced in tanks and their nauplii can be used as food for siganid larval rearing.
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    Influence of lunar cycle and tidal fluctuation of gonadal maturity of green mussel (Pema viridis) in Inner Malampaya Sound, Taytay, Palawan
    Baldevieso, A.A.G. (University of the Philippines Visayas, 2018-07)
    This study aims to identify the ideal period of harvesting cultured green mussel (Perna viridis) in order to attain larger flesh to shell ratio in inner Malampaya Sound, Taytay, Palawan by investigating the gonadal maturity in relationship to lunar cycle, tides, physicochemical and water productivity parameters. Twenty green mussel samples undergo histological analysis of gonad and 50 samples were measured for body indices weekly from October 2017 to March 2018. Results showed that the body and gonad indices have significant positive correlation with slight higher values during the first quarter weeks, and during a day before the low low tides. The peak of spawning was recorded during October. After which, partial spawning was observed and starts during the weeks of full moon until new moon with a duration of 1-3 week. Thus, the gonadal development/maturity of green mussel in the study is influenced by lunar cycle and tidal fluctuations. Among the water parameters monitored, salinity, pH, and temperature have a significant difference in the monthly, and lunar weeks levels. Furthermore, the drop in salinity might trigger the peak spawning. Diatoms (91%) dominate the plankton composition in the sampling area followed by small percentage of dinoflagellates (4%), zooplankton (2%), and cyanobacteria (2%) and ciliates (1%). The genus Coscinodiscus has the highest percentage (97.73%) among the diatom genera, this species could be one of the major algal diet of green mussels in the area. On the other hand, there was no significant correlation between the gonad index and body indices to the physicochemical parameters and water productivity parameters. Based on body indices and gonad index values, the ideal period to harvest green mussel is during the first quarter weeks. One out of 540 samples was found to be hermaphrodite.
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    Semiparametric and parametric modelling of vibro species abundance production system
    Dequito, Angel Queenee D. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2017-09)
    Vibrio species that cause white spot disease and vibriosis are known to be influenced by environmental factors. In this study, the changes in the abundance of presumptive Vibrio species from a biofloc shrimp production system with respect to physicochemical and biological parameters were evaluated. Parametric and nonparametric modelling techniques were used to identify and predict changes in Vibrio abundance in relation to alkalinity, ammonia, dissolved oxygen, nitrite, pH, salinity, temperature, transparency, and phytoplankton and zooplankton densities. Abundance was found to be highly correlated with alkalinity, pH, and phytoplankton density as revealed by both parametric and semiparametric models. Generalized additive model (GAM, a semiparametric model) is the best model based on Aikaike’s Information Criterion (AIC) values in which 41.2% of the variability in the dependent variable can be explained by the predictors compared to ordinary linear regression and negative binomial models (parametric models) with 16.04% and 14.5% respectively. Prediction on the abundance can help prevent bacterial diseases in shrimp as this will provide an insight to the farmer about when to and which water parameters or predictors can be controlled. Thus, it is important to consider the use of semiparametric modelling approach as a tool for fish health management and to prevent losses in aquaculture.