UPV Theses and Dissertations
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Item Spatial distribution of eggs, larvae, and juveniles of Eyebrow goby (Oxyurichthys ophthalmonema) in Batan Bay Estuary, AklanDavid, Alemar V. (University of the Philippines Visayas, 2019-06)ABSTRACT To understand better the biology of eyebrow goby Oxyurichthys ophthalmonema, the spatial distributions of its eggs, larvae and juveniles were investigated in Batan Bay Estuary, Aklan from October 2016 to September 2017 by employing a fisheries- independent methodology. Nesting grounds were located through burrow assessment followed by physico-chemical characterization of identified nesting grounds. Fifteen stations were established all over the study area. Results showed that O. ophthalmonema burrows were present in mudflats all over the study area. Of the 196 burrows assessed in detail, only 34 (17%) burrows had the presence of nesting adult O. ophthalmonema. For the spatial distribution of eggs, they were only found in Moto, Jalas and Kapispisan burrows. The highest observed density was obtained in Kapispisan at 5 eggs/burrow. For the spatial distribution of larvae, they were only found in 9 stations with the Jalas showing the highest density at 32 larvae per 100m3. For the spatial distribution of juveniles, they occurred in all stations but the density was higher in Kapispisan at 4 juveniles per 1000m2. The nesting grounds are located near the upper river tributaries with substantial mudflats and mangrove forest cover. The physico-chemical characteristics of the nesting grounds were as follows: 24.50-26.67ppt for salinity, 29.75-31.25°C for water temperature, 3.26-3.55 for sediment pH (dry weight sediment, DW), 29.82-77.89μg/g for iron (DW sed), 2053-5378μg/g for Sulphur (DW sed), 1.50-8.24μg/g for phosphorus (DW sed), and 0.52-1.15% organic matter (DW sed). The physico-chemical characteristics of the water and sediments of Batan Bay Estuary is favorable to nesting of O. ophthalmonema. There is a need, therefore, to protect these habitats from threats that may negatively affect the nesting of O. ophthalmonema.Item The response of Sandfish Holothuria scabra (Jaeger) juveniles to salinity and temperature changesCaber, Dieyna B. (University of the Philippines Visayas, 2016-02)ABSTRACT Sandfish Holothuria scabra is one of the most economically valuable species of sea cucumbers. Despite being the subject of many research projects and is currently cultured commercially, many of its basic physiological aspects are not yet known or established. This study was conducted to determine the effect of salinity and temperature on the oxygen consumption rate (OCR) of sandfish juveniles. Initially, acclimation to lower salinity was compared to direct transfer. ANOVA showed that the OCR of sandfish juveniles acclimated for 30 and 120 min to 30 and 25 ppt from ambient salinity (35 ppt) were not significantly different (P>0.05) to that of sandfish directly transferred. At 8 h, the OCR values at 30 min acclimation were 0.012 ± 0.002 mgO2/L/h/g at 35 ppt, 0.019 ± 0.004 mgO2/L/h/g at 30 ppt (direct transfer), 0.015 ± 0.001 mgO2/L/h/g at 30 ppt (acclimated), 0.019 ± 0.002 mgO2/L/h/g at 25 ppt (direct transfer) and 0.013 ± 0.002 mgO2/L/h/g at 25 ppt (acclimated). At 120 min acclimation, the OCR were 0.012 ± 0.002,0.019 ± 0.004, 0.015 ± 0.000,0.019 ± 0.002, and 0.013 ± 0.001 mgO2/L/h/g, respectively. In the second part of the study, when sandfish juveniles were exposed to salinities of 35 (ambient salinity) 30 and 25 ppt and temperatures of 34,29 (ambient temperature) and 24 °C over 8 h, their OCR values fluctuated at the highest temperature and even more so at the lowest temperature. Because the experiments at different temperatures were conducted separately, the results could not be compared statistically. However, due to the degree of OCR fluctuation it appears that the sandfish juveniles were stressed at 34 °C and more stressed at 24 °C. This is supported by stress indicators observed visually during the experiment. The absence of OCR fluctuation at ambient temperature (29 °C) indicates that this is the more appropriate temperature for sandfish culture. Based on the results of the study, salinity has no effect on sandfish OCR up to 10 ppt below ambient. These results may be useful for selecting optimal conditions for growth and survival, as well as selecting optimal locations for stock enhancement purposes.Item Comparison of the catching efficiency of the traditional and modified fish corral in Panguil BayAcuña, Rodrigo E. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1997-12)This study was conducted in two fishing sites of fish corral in Panguil Bay namely; Malaubang, Ozamiz City and Maquilao, Tangub City from November 21,1994 to July 10,1995. Two types of fish corral such as traditional and modified were identified. Results showed that average catch per trip was higher in the traditional fish corral (5.1 kg/day) compared to the modified fish corral (4.2 kg/day). The traditional fish corral also have a higher species richness (mean=105 species) against the modified (mean=50 species). About 90% of the catch of the traditional fish corral are commercially important species is significantly higher than the other type (50%). Catches of the traditional and modified fish corral largely consist of shrimps (Metapenaeus ensis: MFC; Penaeus indicus: TFC). Based on the relative density and weight of the total catch, Metapenaeus ensis (mean=222 individuals) is recorded as the most dominant species caught by the modified fish corral while Penaeus indicus (mean=38 individuals) exhibited as a dominant species in the traditional fish corral. Results of the statistical analyses on the data collected on irregular sampling dates show no significant difference on the catches between the traditional and modified. Significant difference is observed on the catches collected during the same sampling dates. Traditional fish corral is more efficient because it has higher catch per trip, species richness and high percentage of commercially important species. Modified fish corral as well, is effective with regards to its catch quantity, however it is inefficient in terms of its catch quality, i.e., of low commercial value.