Masters Theses
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Item The effect of sex reversal treatment on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) raised in brackishwaterBadillo, Susan Delos Santos (University of the Philippines Visayas, 2000-08)A study to determine the effects of sex reversal (SRT) on the growth and survival of two strains of Nile tilapia (Oreochromis niloticus) and Mossambique tilapia (Oreochromis mossambicus) was conducted in four 2m x lm x 1.5m suspended hapa nets in UPV-IA Hatchery and Biology brackishwater fishpond for 75 days. The experimental treatments and codes used in this study were the following, Treatment GGn (GIFT/normal), Treatment GGsrt (GIFT/sex reversal), Treatment MMn (Moss/normal), Treatment MMsrt (Moss/sex reversal), Treatment GEn (GIFT-Egypt/normal) and Treatment GEsrt (GIFT-Egypt/sex reversal). Juvenile fry (average weight 0.0 1g) were subjected to sex reversal treatment by feeding fish diet with methyltestosterone at 60 mg per kg of feed for three weeks in freshwater. After SRT, the fingerlings were nursed in fine mesh net (0.5 mm mesh, 2m x 1m x 1m) for 30 days until the fish attained the weight from 3.0 g to 5.3 g. They were individually tagged by fin clipping method. They were acclimated from 0 ppt to 20 ppt prior to experimental proper. Juvenile fish of 3.40-5.44 g were communally stocked at 25 fish each treatment. Juvenile fish were fed with a commercial feed at 15% of their mean body weight per day from 1-30 days and 10% per day of their mean body weight from day 31-75 days culture period. Within the normal treatments, there was no significant (P>0.05) difference in mean body weights between Treatments GGn and GEn but both are significantly higher (P<0.01) than Treatment MMn. Within the sex reversed treatments, mean body weight in Treatment GGsrt was not significantly (P>0.05) different from Treatment GEsrt, but showed high significant (P<0.01) difference with Treatment MMsrt, similar to the normal treatments. The highest average final biomass of 808.88 g was obtained in Treatment GGsrt followed by Treatment GEsrt (795.58 g) and lowest in treatment MMn (367.63 g). The biomass gain of tilapia within the normal treatments ranged from 282.6 g to 672.95 g. Treatment GGn showed no significant (P>0.05) different from Treatment GEn, but both were significantly higher from Treatment MMn. The same trend was observed within sex reversal treatments. Treatment GGn obtained the highest (589.70%) percentage biomass gain and Treatment MMn (335.01%) was the lowest within the normal treatments. In sex reversal treatment, Treatment GGsrt has no significant difference with Treatment GEsrt, but both showed a high significant difference in Treatment MMsrt. Highest specific growth rate was observed in Treatment GGn (2.62 g day-1) and lowest in Treatment MMn (1.97 g day-1). Mean condition factor (MCF) of tilapia was highest in Treatment GGn (1.60), followed by Treatment GEn (1.56) and lowest in Treatment MMsrt (1.17). Within the normal treatments, Treatment GGn and GEn showed no significant difference (P>0.05), but both were significantly higher (P<0.01) than Treatment MMn. Within the SRT treatment, all treatments showed highly significant (P<0.01) difference from each other with highest at Treatment GGsrt and lowest at Treatment MMsrt. Mean survival ranged from 95% to 100%. Highest percent male population was obtained in hormone-treated fish (95-100%) compared to normal treatments (64-71%). Sex reversal treatment did not improve growth and survival of the two strains of Nile tilapia (O. niloticus), but improved the growth of Mossambique tilapia (O. mossambicus) significantly after 75 days under the conditions this experiment was conducted.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 Survival of nursery-reared juvenile milkfish, Chanos-chanos at different transport density, temperature and anaesthetic combinationsFailaman, Alan N. (University of the Philippines Visayas, 2020-06)Experiments were conducted to optimize transport conditions of nursery cultured juvenile milkfish in a closed plastic bag based transport system. In the first experiment combined effects of temperature (25-27°C, 20-22°C and 15-17°C) and anesthetics (2-phenoxyethanol at 200 mgL-1 for initial sedation and 80 mgL-1 for transport sedation) on oxygen consumption and survival ofjuvenile milkfish, Chanos chanos, were evaluated. Another experiment was conducted to optimize transport conditions at fish densities of 200, 400, 600, 800 and 1000 gL-1 for 4, 8, 12,16 and 20 hour duration. The study showed no significant difference on oxygen consumption rates ofmilkfishjuveniles subjected to various water temperature range and anesthetic combinations. Temperature range of 20 to 22°C in combination with anaesthetic (2-phenoxyethanol) application was the best condition for long duration confinement of milkfish juvenile in closed plastic transport bags. The study established the optimum juvenile milkfish transport density and the effective transport duration. With anaesthetic application (2-phenoxyethanol), juvenile milkfish density of 600 gL-1 is effective for 20 hours oftransport duration, 800 gL-1 for 8 hours oftransport duration and 1000 gL-1 effective for 4 hours transport duration. These results provide a practical protocol for the transport of juvenile milkfish from the nursery culture area to the grow-out production area.Item Effects of dietary pH on growth performance and feed utilization of Nile tilapia (Oreochromis niloticus)Fabay, Ryan V. (University of the Philippines Visayas, 2020-06)Two feeding trials were conducted to investigate the effects of dietary pH (pH 2.5, 3.7, 4.6, 5.7-control, pH 7.0, and pH 8.0) and dietary acid source (acetic acid, citric acid, hydrochloric acid and control-no acid) on growth rate and feed utilization efficiency of the Nile tilapia fry. In addition, attractability indices of the diets at different pH and dietary acid sources were determined. Results of the first feeding trial showed that the feed with pH adjusted to 4.6 resulted in increased growth rate and improved feed utilization efficiency in the Nile tilapia. In the second feeding trial, the use of either hydrochloric, citric or acetic acid in adjusting the pH to the optimal 4.6 did not affect the growth performance of the fish. This study demonstrated that pH and not actually the kind of acid diet promoted growth and efficiency in the Nile tilapia fry. Furthermore, this study provides new information on the use of acid in aquaculture as feed additive for tilapia fry, which can be added to fish feed literature.Item A comparative study of the effects of supplementary feeding and artificial substrate on the production of milkfish fingerlings in brackishwater pondsAdeyemi, Frederick F. (University of the Philippines Visayas, 1983-03)The growth and survival of milkfish fry in response to supplementary feeding and artificial substrate were evaluated at stocking densities of 75 and 100 fry/m2 for a period of 56 days from August 21 to October 15, 1982. The study was conducted in eighteen 40m2 experimental nursery ponds of the University of the Philippines Brackishwater Aquaculture Centre, Leganes, Iloilo. A 3 x 2 factorial experiment in completely randomized design was used and six treatment combinations between level of inputs (no inputs, supplementary feeding or artificial substrate) and stocking density (75 or 100 fry/m2) were investigated with three replicates per treatment. The best fish growth was obtained in Treatment VI (100 fry/m2 with substrate) with mean final weight and length of 1.59 gm. and 5.36 cm. respectively while Treatment IV (100 fry/m2 without feeding or substrate) gave the poorest fish growth with mean final weight and length of 0.83 gm. and 4.60 cm. respectively. Differences in mean weight and length among treatments were, however, not statistically significant. Mean percentage survival was significantly higher at a stocking density of 75 fry/m2 (82.8%) than at 100 fry/m2 (64.1%) but supplementary feeding or artificial substrate ix did not show any statistically significant effect on survival. At either 75 or 100 fry/m2 stocking density, supplementary feeding gave a numerically higher percentage survival than artificial substrate. Economic analysis revealed that a stocking density of 75 fry/m2 without supplementary feeding or artificial substrate was the most profitable treatment with a return on investment of 39.2%. At a stocking density of 100 fry/ m2, supplementary feeding with rice bran was more profitable than the use of artificial substrate with returns on investment of 22.6% and 9.1% respectively.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 Influence of cooling of crab (Scylla spp.) juveniles on the physiological changes and survival during storageGeromiano, Merlyn F. (University of the Philippines Visayas, 2017-06)Considering that aquaculture of mud crabs is still dependent on wild seeds, mortalities associated with capture, handling and storage aggravates the problem of lack of seeds which is one of the major constraints affecting the development of the mud crab aquaculture industry. Having cold rooms for maintaining optimum environment for storage has been recommended, however these facilities are not available in all levels of the industry and can only be found in some of the major traders. To address this issue, this study tested a handling and storage scheme that can be used at various points along the harvest to market chain. In lieu of cooling crabs in a chamber, crabs were directly immersed in seawater of different temperatures (4°C, 7°C, 15°C and 29°C) and stored for 48h, 72h and 96h. Crabs that were cooled at 15°C for 3 min showed highest survival (88-90%) after 48h, 72h and 96h of storage. In addition, the least accumulation of glucose and lactic acid in the haemolymph was detected in crabs cooled at 15°C regardless of the storage period, which suggests that crabs were fess stressed when cooled at this temperature.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 Effect of utilizing a combination of cow and chicken manures as organic fertilizer in fish pondBabalola, Julius (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1986-03)An experiment was conducted utilizing twenty 40m2 ponds to investigate the effect of a combination of cow and chicken manures at the following ratios: 1000 kg/ha chicken manure: 3000 kg/ha cow manure; 1000 kg/ha chicken manure: 1000 kg/ha cow manure; 2000 kg/ha chicken manure only; 4000 kg/ha cow manure only; and no manure (control), on some selected physico-chemical properties of the pond, soil and water, primary productivity and production of red tilapia (0. mossambicus x 0. niloticus hybrid) following an (RCBD) - randomized complete block design. Each pond was stocked with 40 fingerlings of red tilapia and cultured for a 90-day period, at the Brackishwater Aquaculture Center of the University of the Philippines in the Visayas, College of Fisheries, Leganes, Iloilo, Philippines. Soil was analyzed for organic matter, phosphorus, nitrogen, pH, using Walkley and Black method, Olsen’s method, Kjehdahl method and pH meter respectively, following standard procedures described in method of soil analysis part II, (Black, 1965). Water oxygen was determined with YSI model 51-B, oxygen meter, salinity with Goldberg’s T/C refractometer pH with pH meter, phosphorus and NH3 - Nitrogen by methods described by Strickland and Parson, 1972. Reactive phosphorus of pond water improved due to the treatments, and supported fish food production leading to the high net fish yield obtained. Primary productivity, an index of living organisms in the pond, was high and suggests that the different treatments supported adequate fish food production. The highest net fish yield (651.03 kg/ha) was recorded in treatment IV (4 tons/ha cow manure only), while the lowest net yield (299.31 kg/ha) was recorded in treatment V (control). Treatments I (1 ton chicken manure and 3 tons cow manure/ ha) and II (1 ton chicken manure and 1 ton cow manure/ha) produced similar net fish yield, 431.97 kg/ha and 431.95 kg/ha, respectively. Treatment III, 2 tons/ha chicken manure only) gave a better net fish yield of 474.82 kg/ha, than treatments I and II. Cow manure can compare with chicken manure as organic fertilizer, in brackish water fish ponds for tilapia. A combination of 1 ton chicken manure and 1 ton cow manure per hectare could be as productive as 2 tons/ha chicken manure only, in tilapia production.