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Undergraduate Theses

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    Effect of Physico-chemical parameters of rearing waters on survival rates of larvae and post larvae of Penaeus monodon in two hatchery systems
    Alindong, Ray Lauron (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1995-03)
    Physico-chemical parameters such as temperature, pH, salinity, and D.O. of the small-scale and large-scale hatchery system were monitored daily for a duration of two months. The relationship between the physico-chemical parameters and the survival of the different larval and post-larval stages between the two hatchery systems was then determined. Results showed that the physico-chemical parameters obtained from the small-scale hatchery system were favorable to the survival of the larval stages of the prawn. However, the physico—chemical parameters obtained from the large-scale hatchery system were more suitable for the growth of the post-larval stages.
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    Effects of freezing and thawing on some agar parameters of Eucheuma spinosum and Gracilaria confervoides
    Abelende, Ma. Orfa R. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1995-05)
    Agar was extracted from two agar-containing red algae species, namely Gracilaria confervoides and Eucheuma spinosum. Qualitative assessment was made on the agar extracts, which included percentage yield, gel strength, syneresis, and hysteresis range. The quality of agar extracts derived from this study was compared to commercial agar-agar. The. effects of each parameters, repeated freezing and thawing on agar were also investigated. Qualitative test showed that percentage yield from Gracilaria was higher than Eucheuma. Gel strength and hysteresis range of agar from commercial sources and Gracilaria were higher compared to Eucheuma. On the other hand, syneresis range was highest in Eucheuma agar. Repeated freezing and thawing lowered percentage yield and syneresis but increased gel strength and hysteresis of agar extracts from agar sources used.
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    Species composition and food preference of fishes in two seagrass beds in Taklong Island, Guimaras
    Apostol, Archie E. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1997-08)
    Seagrass bed is known as one of the most important biological system that serves as nursery areas, resting and hiding place of small organisms and feeding ground for fishes. Investigations on population structure and composition of fishes have been done to monitor species diversity, abundance, and distribution in seagrass ecosystem. However, few studies have related food preference to community structure. This study aims to determine the species composition and food preference of fishes in Bagatnan and Kalirohan seagrass beds in Taklong Island, Guimaras. Once-a-month sampling in Taklong Island was conducted during the months of October, November, and December 1996. The collection of fishes was done using gill net. It was casted —50 meters from the shore and parallel to the shore during high tide and hauled during the next low tide. All gathered fishes were measured and preserved in 10% formalin. For stomach content analysis, stomachs of fishes were excised, preserved and brought to the laboratory for analysis. Contents were flushed out from the stomach, sorted and identified to major groups (as food items). Based on the results of the study,Siganus fuscecens, Scarus psittacus, and Dichistodus chrysopoecilus were the most abundant species of fish collected in Bagatnan and Kalirohan seagrass beds Kalirohan had a slightly higher species diversity and species richness value than Bagatnan. Most of the fishes caught were omnivores and this feeding mode was clearly reflected in the results of the stomach content analyses Also, the most abundant and common species (e.g. S. fuscecens & Dischistodus spp) had various food items on their stomach. Seagrass blades, algae, foraminiferans and other seagrass-associated organisms (e g. fishes, sipunculids, crustaceans and molluscs) were present in the stomach of many species. Of these, foraminiferans are the most frequently encountered among the food items. A few species fed on single item such as Synodus variegatus, Atherioromorus sp. and Amanses scopes which were found to feed exclusively on fish, algae and seagrass respectively. Although factors like type of fishing gear used and its mesh size and the time of sampling may have biased the kind and size of fish collected, it was clear that the extent of seagrass cover and availability of other food sources (algae and meio- & macrofauna) have influenced the abundance, species diversity & richness and the food consumed (and perhaps, also preferred) by the fish fauna.
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    Anti-microbial activity of aqueous extracts from selected Philippine soft coral species
    Aguilar, Remotito A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1994-03)
    Five species of soft corals were collected from Taklong Islands Guimaras and then extracted with water. The aqueous extract was assayed for anti- microbial activity. Potent extracts were tested for its minimal inhibitory concentration against the most sensitive microorganisms. The equivalent potency was also determined using PEN VK as the standard antibiotic. Lobophyton was found to inhibit S. aureus at 50% concentration of the aqueous extract (ATCC 25923) while Sinuloria. sp. was found to inhibit the growth of both S. aureus (ATCC 25923) and B. subtilis (NSRI-1). Aqueous extracts of Lobophyton sp.has an equipotency of 6.64 units/ml of PEN VK against S. aureus, whereas aqueous extracts of Sinulcria sp. has a potency of 104 units/ml of PEN VK against B. subtilis.