UPV Theses and Dissertations
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Item Effect of salinity on survival and growth of Scylla olivacea crabletsAndres, Eileen Beth N. (Division of Biological Sciences, College of Arts ad Sciences, University of the Philippines Visayas, 2002-04)The effect of salinity on survival and growth of Scylla olivacea crablets was investigated. Salinities of 12, 16, 20, 24 and 32 ppt were used as treatments. Survival, molt interval and growth in terms of weight, carapace length and carapace width were measured for two molts. Growth was measured three days after every molt. There was no significant difference on survival of the crablets between salinities at molt 1. At molt 2, survival was significantly higher at 32 ppt compared to survival at 12 ppt but not significantly different from survival at 24, 20 and 16 ppt. Moreover, duration of survival was significantly higher at 32 ppt than at 16 and 12 ppt but not significantly different from durations of survival at 24 and 20 ppt. On the other hand, molt interval was not significantly different at salinities of 12, 16, 20, 24 and 32 ppt from C1 to C2 and from C2 to C3. Although the highest weight, carapace length and carapace width were observed at 20 ppt at molt 1, there was no significant difference in growth of the crablets at different salinities. At molt 2, the highest weight was at 32 ppt, the highest carapace length was at 24 ppt and the highest carapace width was at 16 ppt and 32 ppt. No significant difference was found in growth of the crablets between salinities at molt 2.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 sodium Iodine -enriched brine shrimp (Artemia salina) on the growth, survival and metamorphosis of Rabbitfish (Siganus guttatus) bloch larvaeLegaspi, Ma. Irene C. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2018-06)Metamorphosis is considered the most crucial stage in larval fish development that dictates the overall larval fish survival and production output in a hatchery system. This physiological process is modulated by thyroid hormones produced from the thyroid gland the biosynthesis of which is dependent on the supply and availability of the mineral iodine. The present study evaluated the supplementation of iodine to rabbitfish (Siganus guttatus) larvae to determine the influence of this mineral on thyroid hormone levels, metamorphosis, growth performance, stress tolerance, and survival. To efficiently deliver iodine to the larvae, the enrichment protocol was optimized by exposing the Artemia to increasing concentrations of this mineral (0.05 g L-1,0.1 g L-1, 0.2 g L-l, 0.4 g L-1 and 0.8 g L-1). The best iodine enrichment treatment was selected (0.8 g NaI L-1) and used to evaluate the influence of this mineral on larval development, growth, metamorphosis, stress tolerance, and survival. Results suggest that growth of rabbitfish in terms of body weight was higher in the treated group (0.20±0.01g) as compared to the control group (0.14±0.01g). This significant growth response is associated with accelerated period of metamorphosis by 11.2 days and a lower muscle fiber count in the treated group (0.003±0.005 μm2-1). Higher levels of triiodothyronine (T3) and thyroxine (T4) were also observed in the group receiving the iodine-enriched Artemia that coincides with the larvae’s accelerated period to metamorphose. T3 in the treated group (15.31±1.22 ng g-1) is higher compared with the control (8.67±1.5 ng g-1) and T4 in the treated group (459.25±136.9 ng g-1) is also higher compared with the control group (170.86±92.55ng g-1) at 27 days after hatching which coincides with the onset of metamorphosis leading to early metamorphosis of larvae in the treated group. In addition, the present results showed that the larvae in treated group were significantly tolerant to stress, quantified as the cumulative stress index (15.33±2.40 CSI) indicating the positive response of the larvae to the dietary iodine enrichment. In summary, sodium iodide-enriched live food (Artemia) accelerated rabbitfish larvae metamorphosis, improved growth and stress tolerance in rabbitfish larvae. The results of this study can be used as a model iodine enrichment protocol to improve the hatchery output of other high-valued marine fish species in culture.Item Influence of sediments of varying grain size composition on growth, survival and burrowing activity of the Ball Sea cucumber, Phyllophorus proteus (Bell,1884) juvenilesAmuenda, Jazriel Ann A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2016-05)Phyllophorus proteus is a high-value sea cucumber species in Philippines but is also one of the most exploited. Hatchery-produced juveniles are used for stock enhancement as a means of restoring depleted population however biology of P. proteus have not yet been studied on. Burrowing incidence of ball sea cucumber P. proteus (Echinodermata: Holothuroidea) juveniles (4-5 length x ≤1mm width), growth, survival and their associated daily behaviour were compared in 3 different substrate collected from Sagay, Negros Occ. (A-mostly coarse), Panobolon, Guimaras (B-intermediate) and Carles, Iloilo (C-mostly fine). This was to establish the most suitable type of substrate to use in the culture system for this high-value sea cucumber. The highest incidence of burrowing was observed in sediment profile C but the difference in the mean number of burrowing individuals between treatments was statistically insignificant (p>0.05). After 4 weeks, growth of P. proteus juveniles was significantly higher (p<0.05) when reared on profile C (growth rate: 0.79±.13mm %d-l) than either profile B (p=0.009) (0.34±0.14 mm %d-1) or profile A (p=0.030) (0.21±0.11mm %d-1). Survival is highest in profile B (S=100%), intermediate in profile C and lowest in profile A although the difference is insignificant (p>0.05) Very fine-fine-grained sediments is the most preferred by ball sea cucumber juveniles while coarse sand seems to be unsuitable.