Masters Theses
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Item Nursery and grow-out culture of mangrove polychaete Marphysa sp.Caballero, Pedrita A. (University of the Philippines Visayas, 2019-12)Experiments on the polychaete Marphysa sp. were conducted to determine the optimum stocking density in indoor nursery as well as the optimum stocking density and culture period in outdoor grow-out ponds that can maximize polychaete biomass production. In the nursery experiment, early metatrocophores at four stocking densities (10,000 m-2; 20,000 m-2; 30,000 m-2; and 40,000 m-2) were tested to determine growth (number of chaetigerous segments) and survival after 7 days in nursery cups. Results showed that the number of segments of early juveniles did not vary significantly (P>0.05) in all treatments. Final number of survivors were higher (P<0.05) at 40,000 m-2 (33,700 ± 1,488 ind.) than 10,000 m-2 (8,300 ± 1,097 ind.), 20,000 m-2 (16,100 ± 1,095 ind.) and 30, 000 m-2 (26,800 ± 1,489 ind.). This suggests that Marphysa sp. juveniles can be produced in high numbers despite high stocking densities using the current nursery protocols. The outdoor grow-out experiment was conducted in a brackishwater pond where early juveniles were stocked at four densities(500 m-2; 1,000 m-2; 1,500 m-2; and 2,000 ind.m-2) attwo culture periods (3 and 4 months) to determine the survival and growth of Marphysa sp. Results revealed that stocking density of 500 ind.m-2 resulted in bigger (P<0.05) polychaetes but total length, survival rate, and biomass were not different (P>0.05) from those in higher stocking densities. Survival rates of the polychaetes did not differ significantly (P>0.05) between 4 months (18.1 ± 12.1%) and 3 months(16.1± 9.2%) of culture. Body weight, total length, and polychaete biomass were all significantly higher (P<0.05) after 4 months of culture compared to just 3 months, suggesting longer culture periods can improve overall yields. The organic matter in sediments decreased from 5% to 4% both in treatments for stocking densities and culture periods, indicating the potential of Marphysa sp as a bioremediation agent.Item Effect of different bio-augmentation agents on the biochemical composition of bacterial floc and growth of juvenile Penaeus monodon cultured in concrete tanksDianala, Rex Delsar B. (University of the Philippines Visayas, 2012-10)The effect of bio-augmentation agents on the biochemical composition of biofloc, growth ofjuvenile Penaeus monodon, and antimicrobial activity of BFT water against Vibrio harveyi was investigated. P. monodon juveniles were cultured in pond soil-lined concrete tanks for 150 d using biofloc technology with bio-augmentation. Three commercial bio-augmentation agents (Pond Protect™, Pond Dtox™, BZT Waste Digester™) were tested against a control with no bio-augmentation agent application. At the end of the culture period, floc and shrimp collected for proximate analysis, and biofloc water tested for activity against V. harveyi. Average body weight (ABW), food conversion ratio (FCR), and specific growth rate (SGR) of the shrimp were computed. Bio augmentation with Pond Protect™ resulted in significantly higher (p < 0.05) crude protein content of the biofloc although this did not translate to higher shrimp yield nor growth performance. BZT Waste Digester™ as bio-augmentation agent significantly increased (p < 0.05) shrimp ABW. No apparent relationship between floc composition and shrimp carcass composition was observed. BFT water, with and without bioaugmentation agents, completely inhibited V. harveyi within 24 h. This study demonstrates that bio-augmentation agents could enhance the biochemical composition offloc and affect shrimp growth. BFT water was also shown to have potent antimicrobial properties against V. harveyi.Item Induction of molting in hatchery-reared mud crab Scylla serrata juvenilesDe la Cruz, Joanna Joy Y. (University of the Philippines Visayas, 2014-03)The effects of lime, temperature and autotomy of chelipeds on growth, survival and molting of mud crab Scylla serrata juveniles were investigated under laboratory conditions. Hatchery produced S. serrata (45-day old) at the intermolt stage with internal carapace width of 2.0-2.3 cm and body weight of 1.7-2.2 g were exposed to lime concentrations of 0, 100, 200 ppm at daily and weekly application, temperature of ambient, 29, 32 and 35 °C and subjected to autotomy. The juveniles were allowed to molt twice prior to termination. The survival of juveniles declined with increasing levels of lime. Mean survival rate of juveniles without lime was 47% while 100 and 200 ppm lime ranged from 29 to 32%. No significant differences were found in the specific growth rate (% SGR) and molt interval (days) in all lime treatments after the first and second molts. All juveniles held in 35 °C had 100% mortality in the first molt due to incomplete molting therefore it was excluded from data analysis. SGR of crab juveniles in the ambient (2.75 ± 0.15%) and 29 °C (3.20 ± 0.18%) were comparable but significantly different (P<0.01) with those juveniles in 32 °C (4.12 ± 0.39%). The molt interval of the crab juveniles after second molt was significantly shorter with increasing temperature (29 °C: 32 ± 0.80 days, 32 °C: 28 ± 1.11 days) compared to ambient temperature (39 ± 0.93 days). The mean survival of juveniles in various temperature levels upon termination was 62, 85 and 65% for ambient temperature, 29 and 32 °C, respectively. Juveniles with intact chelipeds (5.80 ± 0.47%) and one cheliped autotomized (5.45 ± 0.30%) had a significantly higher SGR compared to juveniles with both chelipeds autotomized (4.20 ± 0.52%) in the first molt but no significant difference was observed in the second molt. This trend was observed because the autotomized chelipeds were not fully regenerated after the first molt. The molt interval was significantly shorter in the autotomized juveniles compared to juveniles with intact chelipeds. The interval was 36, 28 and 23 days for intact, one and two chelipeds autotomized, respectively. The survival of juveniles with intact chelipeds (60.61 ± 6.06%) was comparable with autotomized chelipeds (one cheliped: 59.60 ± 4.04%; two chelipeds: 47.22 ± 2.78%). Based on the results, the suggested optimum temperature level for rearing S. serrata juveniles was at 29 °C. Likewise, autotomy of one cheliped can promote molting without adversely affecting the growth and survival of the juveniles. On the other hand, the application of lime did not improve the molting of juveniles due to occurrence of high pH and alkalinity. This also resulted in the low survival and growth of Juveniles.Item Growth development, survival and settlement rate of sandfish (Holothuria scabra) larvae reared using different microalgae and settlement and settlement cuesSibongga, Rema C. (University of the Philippines Visayas, 2017-07)Growth, development and survival of Holothuria scabra larvae fed with different microalgae were studied. In the first experiment, Chaetoceros calcitrans, Rhodomonas sp. and Tetraselmis tetrathele at 10000, 20000, 30000 and 40000 cells ml-1 were compared. Larvae fed with Rhodomonas sp. at 10000 cells ml'1 had the highest mean body length (BL) at late auricularia (1032.41±38.70 μm). However, those fed with C. calcitrans at 20000 cells ml'1 showed higher daily growth rate (DGR) of 31.4±5.2 pm d-1. Development to 50% competent larvae was shorter using C. calcitrans at 20000 and 30000 cells ml'1. At 12 days post-fertilization (DPF), larvae fed with C. calcitrans at 20000 and 40000 cells ml'1 showed significantly higher % doliolaria (p<0.05) and those fed at 20000 cells ml-1 showed highest survival of 53% at 14 DPF. In the second experiment, three combinations of microalgae containing 10000 cells ml'1 of each microalga were used: C. calcitrans and Rhodomonas sp., C. calcitrans and T. tetrathele, and Rhodomonas sp. and T. tetrathele. Larvae fed with mixed C. calcitrans and Rhodomonas sp. showed significantly higher mean BL at late auricularia (991.0±15.8 pm) and DGR (43.8±9.9 μm d-1) (p<0.05). Larvae showed faster development and higher survival of 86% at 10 DPF. In summary, C. calcitrans at 20000 cells ml'1 is recommended as a single diet while a combination of C. calcitrans and Rhodomonas sp. as a mixed diet. Settlement of H. scabra on substrates with different cues was also investigated using corrugated plastic sheets (CPS) as substrate and Navicula, C. calcitrans paste and Spirulina paste as cues. CPS without cue served as control. Although no significant differences, Spirulina paste showed highest settlement rate (88.54%) followed by Navicula and C. calcitrans paste. Control showed significantly lowest settlement rate. Therefore, Spirulina paste best induced settlement of H. scabra. However, Navicula and C. calcitrans paste may be used as cheaper settlement cue substitutes.Item Growth performance, feed utilization and survival against stress test of juvenile Nile tilapia Oreochromis niloticus fed with lactic acid bacteria (lab) Pediococcus acidilacticiSo, April Dawn P. (University of the Philippines Visayas, 2016-06)The present study evaluated the growth performance, feed utilization and survival against stress test of Nile tilapia, Oreochromis niloticus fingerlings (mean initial average body weight 0.39g ± 0.01) fed with commercial probiotics. The experimental design was randomized, with four treatments and four replicates: Treatment 1 (control) with 0g kg-1 probiotics inclusion, Treatment 2 with lg kg1 probiotics inclusion, Treatment 3 with 2g kg'1 probiotics inclusion and Treatment 4 with 4g kg'1 probiotics inclusion. Three hundred and twenty fingerlings were distributed in 16 50L containers and fed for 40 days. Differences in the mean values of total weight were found at the end of the experiment. After 40 days of feeding trial, percent weight gain (%WG), specific growth rate (SGR) and and feed conversion ratio (FCR) was significantly high (P < 0.05) in treatments with probiotics compared to probiotic-free treatments; no differences on survival rate (SR) was observed among dietary treatments. The best growth performance and feed conversion was observed in fishes fed with 4g kg'1 probiotics inclusion. Challenge was done immediately after the period of application. The stress challenge test was done to the experimental animals by exposure to oxygen deficient water or asphyxia. No significant difference (P < 0.05) on SR was observed after 3 hours exposure to asphyxia. It could be concluded that probiotics can improve growth performance and feed utilization. However, further studies are recommended to assess the effects of probiotics to fish when exposed to asphyxia.Item Evaluation of commercial shrimp larval diet as replacement of live foods in mudcrab larval rearingBurlas, Michael Rey J. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2014-04)The use of live food such as rotifer and Artemia entails high cost of production in the hatchery. Hence, the general objective of the study was to reduce the use of natural food in the larval rearing of mud crab. The first study was conducted to screen four types of commercial shrimp formulated larval diet (Lansy, P. japonicus, P. monodon and BP Nippai) in mudcrab Scylla serrata larval rearing. Formulated diets were fed to each stage from zoea 1 to megalopa at an equivalent of 100% dry weight of the live food. Growth index and survival were determined at the end of the experiment. Results showed that of zoea 1 fed any of the formulated diet did not molt to zoea 2. When formulated diets were fed to zoea 2, 3 and 4, there was a decreasing trend in the growth index and survival as the larvae developed. Zoea 5 fed any of the formulated diet failed to molt to megalopa stage. Among the four formulated diets, BP fed larvae had better growth and survival. BP was then used in the second study to determine the amount of formulated diet (FD) that could replace natural food (NF) such as rotifer and Artemia. Results showed that larvae fed 25% FD + 75% NF and 50% FD + 50% NF had better survival and growth than those larvae fed 100% FD + 0% NF, 75% FD + 25% NF and 0% FD + 100% NF. This study indicates that shrimp larval diet in combination with formulated diet can be used to improve the growth and survival of S. serrata larvae.Item Evaluation of different carbon sources used in the biofloc technology (BFT) culture of Litopenaeus vannameiAlaban, Leovigildo Rey S. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)An evaluation of different carbon sources used in Biofloc technology (BFT) culture of L. vannamei was done. The experiment included five treatments: Control, RB (Rice Bran), Tap (Tapioca), Mol (Molasses) and COMBI (Molasses + Rice Bran). Evaluation of biofloc parameters - Total Suspended Solids (TSS) and Settleable Solids (SS)- showed an increasing trend in treatments with molasses (Mol and COMBI) as the culture progressed. This became significantly different (P < 0.05) in the later phase of the culture. The evaluation of environmental parameters included TAN (Total Ammonia Nitrogen), NO2-N (Nitrite Nitrogen) and Chlorophyll a. In treatments with rice bran (RB and COMBI), TAN showed an increasing trend, becoming significantly different with the rest in the later phase of the culture (P < 0.05), while NO2-N were maintained below toxic levels. Chlorophyll a didn’t show any discernable pattern. The effect on L. vannamei was evaluated based on growth (ABW-Average Body Weight, SGR-Specific Growth Rate and FCR- Feed Conversion Ratio) and yield (Survival and Biomass) parameters. Treatments with rice bran showed faster growth rates compared to the rest (P < 0.05) for most part of the culture period. However, analyses of growth parameters based on harvest data don’t show any significant difference in SGR and final ABW for all treatments. Further, poor water quality in these treatments lead to heavy mortalities which caused FCR and Biomass to be significantly different (P < 0.05) from the rest of the treatments.Item Effects of different levels of Pinus tebulaeformis pollen on growth and stress resistance of milkfish fry (Chanos chanos)Baldove, Analyn B. (University of the Philippines Visayas, 2010-06)The present study investigated the effects of different inclusion levels of pine pollen from Pinus tabulaeformis Carr. on the growth performance and stress resistance of milkfish fry (Chanos chanos). Milkfish fry with average body weight of 0.02 g were stocked in 15 tanks (40 fish per tank). A control diet (without pine pollen) and four experimental diets were prepared containing different levels of pine pollen at 0 g kg-1, 1.3 g kg-1, 2.6 g kg-1, 3.8 g kg-1, and 5.1 g kg-1 was fed to the experimental fish for 60 days. At the termination of the experiment, milkfish were subjected to acute ammonia and high salinity shock test. The result of feeding trial revealed that milkfish fed diets containing different levels of pine pollen stowed significantly higher growth (p < 0.05) in terms of weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio than the control diet. Survival of the milkfish during the trial were not significantly different among treatments (p > 0.05). Survival rates of milkfish groups exposed to high salinity stock test for 72 h were not significantly different from each other (p > 0.05). In contrast, results of the ammonia stress test revealed that the survival rates of milkfish fed with the diets containing (2.6 to 5.1 g kg-1) were significantly higher (p <0 .05) than those fed with diets containing 1.3 g kg-1 and the control diet Optimum dietary PP level was estimated using the quadratic model by using SGR and FCR values and found to be is 2.9 g kg-1 and 3.0 g kg-1, respectively. conclusion, pine pollen can be used as a supplement in milkfish diet to enhance growth and stress resistance against environmental stressors like ammonia.Item Influence of lunar cycle and tidal fluctuation of gonadal maturity of green mussel (Pema viridis) in Inner Malampaya Sound, Taytay, PalawanBaldevieso, Adzel Adrian G. (University of the Philippines Visayas, 2018-07)This study aims to identify the ideal period of harvesting cultured green mussel (Perna viridis) in order to attain larger flesh to shell ratio in inner Malampaya Sound, Taytay, Palawan by investigating the gonadal maturity in relationship to lunar cycle, tides, physicochemical and water productivity parameters. Twenty green mussel samples undergo histological analysis of gonad and 50 samples were measured for body indices weekly from October 2017 to March 2018. Results showed that the body and gonad indices have significant positive correlation with slight higher values during the first quarter weeks, and during a day before the low low tides. The peak of spawning was recorded during October. After which, partial spawning was observed and starts during the weeks of full moon until new moon with a duration of 1-3 week. Thus, the gonadal development/maturity of green mussel in the study is influenced by lunar cycle and tidal fluctuations. Among the water parameters monitored, salinity, pH, and temperature have a significant difference in the monthly, and lunar weeks levels. Furthermore, the drop in salinity might trigger the peak spawning. Diatoms (91%) dominate the plankton composition in the sampling area followed by small percentage of dinoflagellates (4%), zooplankton (2%), and cyanobacteria (2%) and ciliates (1%). The genus Coscinodiscus has the highest percentage (97.73%) among the diatom genera, this species could be one of the major algal diet of green mussels in the area. On the other hand, there was no significant correlation between the gonad index and body indices to the physicochemical parameters and water productivity parameters. Based on body indices and gonad index values, the ideal period to harvest green mussel is during the first quarter weeks. One out of 540 samples was found to be hermaphrodite.Item Semiparametric and parametric modelling of vibro species abundance production systemDequito, Angel Queenee D. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2017-09)Vibrio species that cause white spot disease and vibriosis are known to be influenced by environmental factors. In this study, the changes in the abundance of presumptive Vibrio species from a biofloc shrimp production system with respect to physicochemical and biological parameters were evaluated. Parametric and nonparametric modelling techniques were used to identify and predict changes in Vibrio abundance in relation to alkalinity, ammonia, dissolved oxygen, nitrite, pH, salinity, temperature, transparency, and phytoplankton and zooplankton densities. Abundance was found to be highly correlated with alkalinity, pH, and phytoplankton density as revealed by both parametric and semiparametric models. Generalized additive model (GAM, a semiparametric model) is the best model based on Aikaike’s Information Criterion (AIC) values in which 41.2% of the variability in the dependent variable can be explained by the predictors compared to ordinary linear regression and negative binomial models (parametric models) with 16.04% and 14.5% respectively. Prediction on the abundance can help prevent bacterial diseases in shrimp as this will provide an insight to the farmer about when to and which water parameters or predictors can be controlled. Thus, it is important to consider the use of semiparametric modelling approach as a tool for fish health management and to prevent losses in aquaculture.