Undergraduate Special Problem
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Item Effects of pH and salinity on growth and survival of juvenile sea cucumber Holothuria scabra (Jaeger, 1833)Abagat, Christian M. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2012-03)Sea cucumber aquaculture could provide a solution to both enhance declining wild sea cucumber populations through restocking and provide sufficient beche-de-mer product to satisfy the increasing Asian market demand. The growth and survival of hatchery-reared Holothuria scabra juveniles at different pH-salinity levels were investigated. Juveniles were exposed for 14 days in six pH-salinity levels: Trt 1 (pH 6.5 — 6.7, 26-28 %o), Trt 2 (pH 6.5 - 6.7, normal salinity), Trt 3 (pH 7.0 - 7.2, 26-28 %o), Trt 4 (pH 7.0 — 7.2, normal salinity), Trt 5 (normal pH, 26-28 %o) and Trt 6 (normal pH, normal salinity) as the control. Multivariate analysis of variance (MANOVA) with repeated measurements revealed that pH and salinity had a significant effect on growth (length, width, and weight) and survival of H. scabra juveniles. Slight seawater desalination combined with high acidification (pH: 6.5-6.7) had lethal effects on H. scabra juveniles. While H. scabra juveniles could be reared in seawater with pH ≥ 7.0- 7.2 and salinity ≥ 26-28 %o, ambient seawater conditions remained the most suitable in rearing H. scabra juveniles for optimum growth and survival.Item Effects of crude methanolic extract of purple nutgrass (Cyperus rotundus L.) on the maturation of golfish oocytesAcebuque, Florel May C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2014-04)Cyperus rotundus L. is a pernicious weed, which is traditionally used for different medical purposes and is locally recommended for antifertility purposes. A number of pharmacologically important constituents have been previously isolated from the plant. This study aims to test the effects of the crude methanolic extract of C. rotundus L. on the maturation of goldfish oocytes. The extract is found to induce 100% maturation at 5 mg/mL concentration. However, it becomes toxic at higher concentration. All goldfish oocytes (100% ) has died at 20 mg/mL concentration. The steroids and flavonoids present in the plant may be responsible for inducing goldfish oocyte maturation, whereas the alkaloids may be toxic to the oocytes. Further studies using mammalian systems in vivo and characterization of individual constituents are recommended.Item Species composition and distribution of fish larvae in Lianga Bay, Surigao del SurAcabado, Cristy S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2007-03)The species composition and distribution of ichthyoplankton in Lianga Bay, Surigao del Sur was investigated in June 2004. A total of 37 families were recorded from horizontal tows collected in 32 sampling stations. The most dominant larvae were Gobiidae and Pomacentridae, which comprised 20.4% and 16.0% of all larvae sampled, respectively. Overall larval density was 4.2 ind. 100 m-3 (n=32; sd=5.0), with highest concentrations in the inner portion of the bay particularly in the west and southwest portions. On the other hand, egg density (mean=0.9 eggs m-3; n=32; sd=0.9) showed highest concentration near the coastline but further from the central basal portion of the bay. Patches of high egg concentrations suggest that Lianga Bay may serve as spawning ground for some species.