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UPV Theses and Dissertations

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1992 - 19963

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Adviser: search.filters.advisor.Baylon, Juliana C.End date: 1999

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    The effect of different levels of salinity on the spanning of ablated mudcrab Scylla serrata
    Bueno, 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.
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    Embryonic development and hatching rate of grouper (Epinephelus suillus) eggs incubated at different stocking densities
    Bofill, Aileen B. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1992-04)
    Fertilized eggs of the grouper Epinephelus suillus were obtained from natural spawning of broodstock reared in a 50—t concrete tank at the Aquaculture Department of the Southeast Asian Fisheries Development Center, Tigbauan, Iloilo. The development of eggs incubated at three different stocking densities (50, 1OO, and 150 eggs/1) were monitored. Hatching rates in the different treatments were also determined. Fertilized eggs were floating, non—adhesive, transparent, and spherical in shape with a mean diameter range of 0.83 — 0.84 mm. The yolk was colorless, transparent, and possessed a single oil globule of 0.22 mm in diameter. The eggs have developed into the 2—cell stage 45 min after stocking. Eggs incubated at 1OO eggs/1 hatched 24 h after stocking, while hatching occurred after 27 h and 5 min at 50 eggs/1. No hatching was observed at 150 eggs/1 stocking density even after 28 h post—stocking. Water temperature and salinity during the experiment were 27 ° C and IB ppt, respectively.
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    Larval rearing of Scylla serrata Forskal: The effect of Artemia salina and Brachionus plicatilis as food on the growth and survival of zoea
    Apote, Ma. Noemi G. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1996-11)
    A study was conducted to find out tile effects of Artemia, Brachionus and a combination of Anemia and Brachionus as food on the survival of mudcrab Scylla serrata Forskal zoea and the ability of the zoea to metamorphose to megalopa stage. The study composed of three experiments. Each experiment lasted for 21 days. Results showed highest mean percent survival (66.7±2.03) on zoea fed with a combination of Anemia and Brachionus at a feeding density of 5 individuals/ml each. When the density of Brachionus was increased from 5 individuals/ml to 12 individuals/ml in the combination diet, there was an increase in the survival of the zoea to 68.9±2.41. Highest metamorphosis from zoea to megalopa was also obtained on those fed with a combination of Anemia and Brachionus. This combination diet also gave the shortest number of days for the zoea to metamorphose to the next stage which also resulted to the least number of days for megalopa production to start. The study also revealed that larvae ted with a combination of Anemia and Brachionus reared at 30 ppt salinity got high survival on the first three days of culture, however starting on the 4th day up to the 15th day of culture, those reared at 28 ppt obtained higher survival although not statistically different from the other salinities tested.