UPV Theses and Dissertations
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Item The effect of different levels of salinity on the spanning of ablated mudcrab Scylla serrataBueno, Jesse L. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1994-04)Four salinity treatments with salinity levels of 15 ppt, 25 ppt, 35 ppt and 45 ppt with six replicates per treatment were utilized to determine its effect on the spawning of sexually mature bilaterally ablated mud crab Scylla serrata. The crabs range in weight from 250 grams to 580 grams and carapace width from 12.5 cm. to 16.5 cm. The results of the study showed significant difference (P<0.05) in the number of days when spawning occurred. The shortest duration when spawning occurred was at 25 ppt salinity with a mean value of 9.5 days. This was followed by 35 ppt and 15 ppt salinities with mean values of 15.69 days and 19.83 days respectively. Highest number of days when spawning occurred was at 45 ppt salinity at 24 days. All crabs died 2-3 days after spawning.Item Survival and growth of the sea cucumber Holothuria scabra (Jaeger) juveniles reared at different dietsBaylon, Basil C. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2009-03)Sea cucumbers are economically important species, with high demand in local and international markets. Overharvesting due to this high demand causes depletion of wild populations of sea cucumbers. Stock enhancement has been resorted to improve the status of natural populations. This will need the development of rearing technology which includes studies on the effects of different diets on sea cucumber juveniles. In this study, the effects of five diets on growth and survival of sea cucumber Holothuria scabra juveniles were compared. The five treatments used were benthic diatoms (Navicula sp.) alone, combination of benthic diatoms and seaweed (Sargassum sp.) extract, seagrass extract alone, combination of benthic diatoms and seagrass (Thalassia sp.) extract, and commercial shrimp feed. Three replicates were used for each treatment. For every replicate. 10 juveniles with body length 1-2 mm were reared in a 3-L culture container with seawater and no sand substrate. Salinity ranged from 32-35 ppt and the temperature from 26-29°C. It was observed that there was a trend of increasing body weight, body length, and body width of juveniles as weeks of culture progressed. After 7 weeks of culture, best weight gain, increase in body length and body width was achieved in juveniles fed with either benthic diatoms alone or combination diet of benthic diatoms and seaweed extract. There was high survival in all feeding treatments except in H. scabra juveniles fed with commercial shrimp feed. The lowest body weight, length and width and lowest survival were consistently obtained from juveniles given commercial shrimp feed.Item A study on spawning induction of Imbaw Anodontia edentula (Linne, 1758)Bacaro, Teressa Mae D. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2008-03)The mud clam, Anodontia edentula, was induced to spawn using extract from ripe and developing gonads. Clams responded to the spawning stimulus by extension of the foot, swelling and extension of the mantle, swirling of the whole body, rapid opening and closing of the valves, ejecting of white material from the excurrent siphon, and subsequent contraction of the adductor muscles. Successful spawning of all individuals occurred with the use of gonad extract. Developing homogenized extract was not as effective in inducing the broodstock to spawn. Gametes were released through the excurrent siphon located at the posterior end.