http://hdl.handle.net/10862/3258 2026-04-09T08:43:37Z http://hdl.handle.net/10862/3309 Competitive and comparative advantages of brackishwater aquaculture of tiger shrimp, mud crab, and milkfish in the Philippines in 1985-1995 Gonzales, Leonardo A.; Elca, C. D.; Gonzales, V. A.; Alviola IV, Pedro A.; Paraguas, F. J.; Olalo, C. Bagarinao, Teodora The brackishwater aquaculture sector contributes considerably to the growth of the fisheries sector. Tiger shrimp Penaeus monodon, mud crab Scylla serrata, and milkfish Chanos chanos, in particular are efficient users of domestic resources and earners of foreign exchange. These three commodity sectors have not been fully developed because of inadequate policies in research, technology generation, and extension, and in public investment and support services in production, marketing, and post-harvest processing. Our analysis used the domestic resource cost approach. The average resource cost ratios for the Philippines were 0.44 for tiger shrimp, 0.66 for mud crab, and 0.35 for milkfish. If the peso overvaluation is corrected, the comparative advantage can be dramatically enhanced with respective resource cost ratios of 0.36 and 0.55, and 0.28. Given the current international market and production technologies for these commodities, competitive and comparative advantage can be sustained above the breakeven border price per kilogram of US$6–7 for tiger shrimp, US$5–6 for mud crab, and about US$1 for milkfish. The actual border prices per kilogram during the past five years have been higher at US$12.34 for tiger shrimp, US$8.39 for mud crab, and US$2.39 for milkfish. At current domestic costs and border prices of the these commodities, the advantage in exports may be sustained at yields per hectare greater than about 2 mt tiger shrimp, 100 kg mud crabs, and 500 kg milkfish. To enhance the efficiency of production of these commodities, the following areas of intervention are needed: <ul><li>Technology improvements in seed production from the hatchery of tiger shrimp, mud crab, and milkfish</li><li>Research and technologies for diagnosis, prevention, and control of diseases of tiger shrimp (e.g. luminous bacteria)</li><li>Training in farm management to enhance the skills of small-scale pond operators</li><li>Public investments in infrastructures and support services including credit access to enhance efficient flow of goods and services from the farm to strategic market outlets</li><li>Market development to ensure sustainable outlets for brackishwater pond production</li><li>Reforms in trade and exchange rate policies to enhance global competitiveness</li></ul> 2007-01-01T00:00:00Z http://hdl.handle.net/10862/3307 Bacteria and toxin isolated from the dinoflagellate Pyrodinium bahamense var. compressum and production of monoclonal antibodies and diagnostic kits to monitor red tide and toxic mussels Espino, T. M.; Aspiras, R. M.; Sabino, N. G.; Parreño, E.; Macasadia, R. L.; del Mundo, M. L. F. Bagarinao, Teodora Six bacterial isolates obtained from the red tide dinoflagellate Pyrodinium bahamense var. compressum were found to be toxic. The most toxic isolate MM-11 was cultured, characterized, and identified to be Micrococcus luteus. MM-11 and M. luteus had similar DNA bands on agarose gel, and contained 70.0–75.5% mole G+C. Several Micrococcus species were isolated from pure culture and field samples of Pyrodinium and from red tide affected mussels. MM-11 and the other Micrococcus isolates tested positive for saxitoxin. MM-11 was grown on seawater agar; peak cell density of 1.36 x 1010 cells/ml occurred after 3 days of incubation. Toxin production was directly proportional to cell density. The crude toxin from the optimized culture of MM-11 resulted in death of mice in only 1.8–2.4 min, equivalent to a toxicity of 5.9–13.4 mouse units. MM-11 was inoculated into healthy mussels and yielded bacterial isolates that had characteristics of MM-11, and extracts of toxin similar to MM-11 toxin. Mice injected with extracts from the inoculated mussels showed symptoms of paralytic shellfish poisoning (dyspnea 12–15 min after injection), but did not die. Partially purified extracts from red tide affected mussels killed mice in 3.4 min, equivalent to a toxicity of 3.4 mouse units. Addition of 5, 25 and 50% coconut milk to this toxin extract reduced the toxicity to only 34%, 29%, and 25% of that without coconut milk. The ELISA test similarly showed reduction of saxitoxin concentration from 4.78 g toxin/g at 5% added coconut milk to 3.62 g toxin/g at 50% added coconut milk. PSP toxins were extracted from bacteria and red tide affected mussels. The 24 purified extracts of MM-11 toxin were shown by mouse bioassay to have concentrations from 0.6 to 71.6 μg toxin/g bacteria. Green mussels sampled from Bataan and Zambales during incidence of red tides from 1994 to 1998 contained lower amounts of toxin per unit weight than the bacterial extracts. Analysis of the MM-11 toxin by HPLC-fluorometry showed two fractions similar to those of standard gonyautoxin 1 and gonyautoxin 3. 2007-01-01T00:00:00Z http://hdl.handle.net/10862/3302 Development of various value-added products from 'aloy' or bullet tuna Auxis rochei Santos-Yap, Encarnacion Emilia M. Bagarinao, Teodora The recommended steps in new product development were followed to utilize bullet tuna maximally. New products were generated, evaluated, and refined. Three product concepts were initially advanced to the product optimization stage; both product and positioning blueprints were created. The products were optimized in terms of the levels and combinations of additives and spices, and the organoleptic properties were evaluated. The new products—bullet tuna loaf, seasoned dried bullet tuna, canned spicy bullet tuna, and canned pet foods—were tested for shelf-life. Tuna loaf treated with potassium sorbate remained acceptable for 29 days at 0°C, whereas untreated samples remained acceptable for 26 d at 0°C, 16 d at 14°C, and 3 d at 35°C. Seasoned dried tuna was still acceptable until 15 d in storage at 0°C and until 6 d at 35°C. Canned spicy tuna remained acceptable after more than a year of storage at 35°C. Cost analysis based on the current retail prices of bullet tuna (P30/kg), additives, spices and other raw materials showed that the production costs were: P19 for 100 g of bullet tuna loaf; P2 for a piece of seasoned dried tuna; and P 12.5 for a can of spicy bullet tuna. Traditional processing methodologies were applied to bullet tuna as raw material. Smoking and dry-salting yield bullet tuna products that can be offered to the consumers at prices much lower than those of the newly developed value-added products. 2007-01-01T00:00:00Z http://hdl.handle.net/10862/3300 Demonstration of tilapia-carp polyculture in lowland and highland farms Palma, Adelaida L.; Pol, Romy M.; Diamante, Adan Samuel Bagarinao, Teodora Technology demonstration was conducted in three selected lowland freshwater ponds in Lucban, Quezon and in three highland ponds in Ifugao. The ponds varied in location, size, water source, and operators. The polyculture system included 60% Nile tilapia, 30% common carp, and 10% bighead carp, seeded at a density of 5/m². Two lowland ponds had total production of 4,737 and 4,416 kg/ha-yr (8.83 kg/m³ and 6.77 kg/m³). One highland pond yielded 2,786 kg/ha-yr (11.14 kg/m³). Survival rates were better in lowland areas, mostly because the farmer cooperators had better training and more experience. Costs-and-returns analysis showed high profitability of tilapia-carp polyculture. With proper management, polyculture can produce fish and increase farmers‘ incomes, even during the off-season for traditional crops. 2007-01-01T00:00:00Z