Recent Submissions

  • Book chapter

    Agricultural run-off and pollution in Imbang River, Negros Occidental 

    GA Gonzales - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    This study determined the concentration of key pollutants carried by agricultural run-off from the drainage area of Imbang River, Negros Occidental over a two-year period. The quantities loaded into the river were estimated to assess the contribution of agriculture to the degradation of the river. Agricultural production in sugarcane and rice plantations in the area relied on chemicals to control pests and enhance production. Run-off from agricultural land contained an average 0.2 ppm phosphate, 0.2 ppm ammonia, 0.02 ppm nitrite, and 1.7 ppm nitrate from fertilizer inputs and other sources. The run-off also had 7.4 ppm biochemical oxygen demand, 465 ppm total solids, 296 ppm total suspended solids, 0.4 ppm settleable solids, plus traces of organochlorine pesticides. The concentrations of all these potential pollutants were not alarming or dangerous, although on occasion, some exceeded the tolerable limits. However, increasing reliance on fertilizers often leads to intensified use and related problems. Likewise, the continuing use of chemicals to control field pests is of serious concern given that residues are easily carried by run-off to the nearest waterway and passed on and magnified through the food chain. The health of farm workers who routinely handle these products is at risk. Apart from commercial fertilizers, farm lands received organic wastes from domestic and industrial sources. Most farmers maintained farm animals such as carabaos, goats, and sheep that were allowed to graze on the fields after crops had been harvested. Grazing animals frequently left surface deposits of manure. Some farmers on occasion used sugar mill wastes as fertilizers and road fillers in the haciendas. Moreover, household wastes including human excreta were commonly disposed on nearby fields. The contributions of animal and human wastes to the total load of nutrients could be substantial but difficult to quantify given the manner of production and the varying composition of the wastes. Indeed, agricultural run-off transports non-point pollutants from so many poorly defined sources.
  • Book chapter

    The fish processing industry in Central Luzon and the processors' assessment of the extension program of the Department of Agriculture 

    MS Morata - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    A survey was done in 1992 of 242 fish processors in Region III or Central Luzon: 57 in Bataan, 39 in Bulacan, 24 in Nueva Ecija, 45 in Pampanga, 41 in Tarlac, and 36 in Zambales. The fish processors were engaged in three major fish processing enterprises: fish smoking (52%), fish drying (17%), and fish fermentation (31%). The products were smoked fish ‘tinapa’, dried fish ‘daeng’, fish paste ‘bagoong’, rice-fish paste ‘buro’, and fish sauce ‘patis’. Most of the processors in Zambales, Bataan, and Bulacan produced bagoong; ‘buro’ was produced only in Pampanga. Of the processors, 105 were small-scale operators, most of them in Pampanga, Bataan, and Bulacan, who had average capital of P11,000, worked an average of 3 days a week, and processed an average of 5,000 kg of fish a year. The 90 medium-scale processors had average capital of P20,000 and handled between 5,000 and 20,000 kg of fish a year, 5 days a week. The 47 large-scale processors, mostly in Zambales, Bataan, and Tarlac, invested an average of P94,000, and handled more than 20,000 kg of fish a year, seven days a week. The 242 fish processors in Region III in 1992 employed 501 people, 47% of them family members. The total production of processed fish products was about 73,000 kg a month, including about 21,511 kg ‘tinapa’, 4,790 kg ‘daeng’, and 46,634 kg ‘bagoong’. Processors in Zambales fermented the most fish, about 23,000 kg/month, followed by those in Bulacan. Among those in fish smoking, Bataan processors produced the biggest volume of 5,900 kg/month. Fish drying was done only in Bataan and Bulacan, and Bataan processors produced about 2,800 kg/month. The fish processors in Region III sold their produce three ways: wholesale, retail, and contract buying. They followed a simple marketing plan, using outlets in nearby towns and cities, including Metro Manila. For six months of operation, the cost was lowest in fish smoking and highest in fish drying. Gross sales was also lowest in fish smoking, but highest in ‘bagoong’-making. Net profit was lowest in fish smoking and highest in ‘bagoong’-making. Return on investment was 38% in fish smoking, 41% in ‘bagoong’-making, but only 19% in fish drying. More than one-half of the processors earned incomes of P20,000–35,000 a month, one-fifth earned less, but one-fourth earned more.

    Fish processors in Region III in 1992 were on average 46 years old; nearly 80% were 26–55 years old and only two were younger than 26 years. There were more women than men in fish processing, particularly in Bataan, and about 93% were married. The respondents had formal education, but 60% did not go beyond elementary school. The respondents had considerable experience in fish processing, 60% of them having been in the business for 5–20 years, and 19% of them for even longer. Many reported household expenditures of P1,000–3,000 a month, but some also as high as P6,000–7,000 a month. The processors owned household appliances and furniture, and a few owned motorized boats.

    The Department of Agriculture provided extension services and credit to fish processors in Region III. Services included technical assistance, direct consultation, field visits, lectures, demonstrations, training, seminar, and preparation of feasibility study when availing of loans. Most fish processors in Bulacan considered extension services important, but most of those in Nueva Ecija were indifferent to extension services, apparently because they already had the needed knowledge and skills. In Pampanga, the older processors and those with greater investment considered extension services very important. In Zambales, processors with more experience required less extension services. In Bataan, gender, education level, investment, civil status, and income significantly influenced the processors’ assessment of the importance of extension services and the extent of their participation in the government’s extension program. Women considered it very important to avail of extension services, especially those who were married and those with little formal education.
  • Book chapter

    Water quality in Imbang river, Negros Occidental: effluents and pollutant loads from agriculture, sugar mills, households, and shrimp farms 

    GA Gonzales, HJ Gonzales, RC Sanares & ET Taberna - In TU Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    An ecological assessment of Imbang River in Negros Occidental was undertaken from December 1992 to February 1995. The effluents from sugar mills, households, shrimp farms, sugarcane plantations and rice fields were characterized and their pollutant loads estimated. Water quality and invertebrate assemblages were analyzed at several sites along the river to determine the environmental status. Results showed significant seasonal and site variations in water quality along Imbang River. The dry season, coinciding with the milling season, was the more critical time of the year as water quality tended to deteriorate. The segments of the river near the sugar mills and households had the poorest water quality. Sugar mill effluents had high water temperature (average 33oC but as high as 50oC), low dissolved oxygen, high total solids, the highest settleable solids (average 2.5 and as high as 17 m/l), and the highest biochemical oxygen demand (average 259 ppm but as high as 14,800 ppm BOD). Domestic effluents had low pH, high ammonia, very high BOD, plus detergents or surfactants and high levels of fecal coliform bacteria. Agricultural runoff had high nitrate, high total solids, and the highest total suspended solids (average 296 ppm but as high as 5,095 ppm TSS). Shrimp ponds used saline water of average 23 ppt, and had the highest total solids (average 23,456 ppm and as high as 57,400 ppm). By far the major contributor of pollutant loads into Imbang River was agriculture, due to its huge areal extent and huge volume of water use and run-off. Agricultural run-off carried the highest annual loads of 7,858 kg phosphate; 6,495 kg ammonia; 794 kg nitrite; 67,212 kg nitrate; 16,987 metric tons settleable solids; 16,800,000 mt total solids, and 11,890,000 mt total suspended solids; but only 297 mt BOD. Sugar mill effluents had the highest BOD load (1,583 mt/yr) and also had high nutrient loads. Household effluents contributed the second largest loads of solids next to agriculture, and also added surfactants (966 kg/yr) and fecal coliforms into the river. The six shrimp farms at the lower reaches of Imbang River were a minor contributor of pollutants into the river, annually adding about 891 kg ammonia; 1,077 kg phosphate; and 181,325 mt total solids.
  • Book chapter

    Fish catch and fisher incomes before and after installation of artificial reefs in Panguil Bay, northern Mindanao 

    HP Moncay & LP Cablo - In TU Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Two artificial reef complexes (10 modules) were deployed in Panguil Bay in 1990. The effect of the ARs on the fish catch and fisher incomes was studied from March 1993 to April 1994 in Purok 3, 4, 6, and 7 in San Antonio, Ozamis City and in Poblacion 1 and 4 in Clarin, Misamis Occidental. Clarin‘s 40 full-time fisher respondents had 50 outrigger boats, all without engines, and used 181 fishing gears, 93% of them simple or multiple hand lines. San Antonio‘s 80 full-time fisher respondents had 87 non-motor boats and 44 motor boats and used 489 fishing gears, 86% of them bottom-set gill nets. The fishers worked an average of 19 days a month and four hours a day. The fishing grounds were mostly between 3 and 3.5 km from shore, and the gears were operated in waters about 50 m deep. Of about 17,000 kg of fish harvested in Clarin and San Antonio over one year, 33% came from bottom-set gill nets, 32% from bottom-set long lines, and 28% from multiple hand lines. The catch included a great variety of fishes, plus shrimps and cuttlefish; threadfins made up 13% of the total volume by weight, slipmouths 10%, and sardines 7%. The catch ranged from 2,382 kg valued at P75,862 in Purok 3 to 3,212 kg worth P97,303 in Poblacion 1, but in Purok 7, the catch was 2,965 kg worth P123,195. The average annual revenues of fishers was P24,191 in San Antonio and P11,472 in Clarin, corresponding to monthly earnings of P2,016 and P956, respectively. The revenues and net incomes were low, but the returns on investment were high (78–300%). The fishing boat, with or without engine and gas, was the major expense incurred by the fishers. Between 1989 and 1993–94, the volume of fish catch increased two-fold in San Antonio and four-fold in Clarin. The average annual income of fishers in the six villages increased by 10–60% after the ARs, and the average annual expenses also increased by 5–30%. In 1993-94, the computed return on investment was 105% in San Antonio and 274% in Clarin, higher than in 1989.
  • Book chapter

    Giant squid Thysanoteuthis rhombus caught by jigs in Calauag Bay, southeastern Luzon 

    JO Dickson & RV Ramiscal - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Test fishing for the giant squid Thysanoteuthis rhombus using large jigs was conducted in selected areas around Alabat Island, Quezon Province from May 1991 to October 1992. A total of 92 fishing days and 425.3 fishing hours were successfully completed and 1,650 jigs were set. The total catch was 82 giant squids of total weight 412 kg. Catch per unit effort was on average 0.02 kg/jig-hour or 5 squids/100 jigs, but higher from July to September. Capture of the giant squid by jigs was very seasonal, only from June to October. During these months, fish aggregating shelters were installed to catch pelagic fishes, and these shelters may have attracted the giant squid to Calauag Bay. The sample of 82 giant squids adds considerable information to the biology of this species in Philippine waters. The smallest specimen, caught in August 1991, was 23 cm in mantle length and 750 g in weight. The largest specimen, caught in September 1992, was a male 69 cm in mantle length and 10.3 kg in weight. Of the 66 specimens examined, 31 were males and 35 were females. About 52% of the specimens were sexually mature, 30% were maturing, and the rest were immature. Of the 61 stomachs dissected, 20 were empty, six were full or 3/4 full, and the rest were in between. The giant squid was a fish eater, almost all stomachs containing fish bones, spines, scales, or digested fish meat.
  • Book chapter

    The squid fishery in Carigara Bay, Samar: catch of Photololigo duvaucelii by squid jigs and Sepioteuthis lessoniana by hanging squid pot 

    JO Dickson & BR Ricafrente - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    The squid fishery in Carigara Bay used the following gears: hanging squid pots, squid jigs, drive-in net, and spear by slingshot. Hanging squid pot operations were concentrated in the municipal waters of Capoocan and Carigara and targeted Sepioteuthis lessoniana. During the one-week survey in Carigara Bay, 705 hanging squid pots with markers were found offshore of barangays Culasian, Pinamopoan, Cabul-an and Talarian, all in Capoocan town. Other operators in Carigara, Babatngon, Barugo, and San Miguel towns hung their squid pots from fish shelters (arong) offshore of Carigara and Capoocan towns. Test fishing operations were conducted in Carigara Bay from January to December 1992 using the hanging squid pot, squid jigs, and a squid cast net. A 16 hp motorized boat F/B Ellah Meh was used during the fishing operations. A total of 162 days test fishing with 15 hanging squid pots yielded 125.7 kg of the longfin squid Sepioteuthis 1essoniana. Sixty nights of fishing with the ordinary squid jig yielded 97 kg of Indian squid Photololigo duvaucelii. Two test fishing operations with the squid cast net yielded no squid at all. The S. lessoniana (75-500 g body weight) caught by pots were larger than the P. duvaucelii (7-270 g) caught by jigs.
  • Book chapter

    Improved production of mud crabs Scylla serrata in marine pens with used tires and bamboo tubes as shelters 

    MC Basaya - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    One serious problem in mud crab farming systems is cannibalism and low survival, but this can been offset by provision of shelters. Two types of shelters were tested on mud crabs grown in bamboo pens set in a mangrove area in Tiniguiban Cove in Puerto Princesa. Six pens, each 3 m x 3 m in area, were built side by side (the whole array 9 m x 6 m in area). Two pens were provided bamboo tubes, two had used tires, and two had both shelter types. The bamboo tubes were about 46 cm long and 13 cm in diameter, open on both ends, and each with a node retained as partition. The bamboo tubes were laid in one layer at the middle of the pens, 48 tubes in each of the two pens. The used tires were 50 cm in diameter, placed 20 cm apart in one layer in the middle of the pens, 12 tires in each of two pens. In the two pens that had both shelter types, half the number of bamboo tubes and used tires were laid out. All shelters were tied and did not move off the bottom. Juvenile crabs of 46 g body weight were stocked at 63/pen or 7/m2. The crabs were fed chopped trash fish at 5% of body weight daily at 0800 h and 1600 h. Mud crabs in the pens with bamboo tubes as shelters had the best survival (79%), weight gain (81 g), net production (4.5 kg/pen), and feed conversion ratio (4.9), as well as net income (P544,202/ha-yr) and return on investment (48%). The results clearly indicated that bamboo tubes were better shelter for juvenile mud crabs than used tires. Bamboo tubes were presumably more familiar to mud crabs reared in bamboo pens. Having node partitions in the middle, the bamboo tubes had smaller and safer hiding places. These shelters effectively reduced crowding, aggression, and cannibalism, and thus increased the survival and growth of mud crabs. The used tires evidently did not provide a good shelter configuration nor sufficient protection for mud crabs in bamboo pens.
  • Book chapter

    Bacterial loads in hatcheries and virulence of Vibrio spp. to larvae of the tiger shrimp Penaeus monodon 

    JL Torres - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Shrimp hatcheries are high-density systems and are prone to diseases. A small-scale and a large-scale hatchery for the tiger shrimp Penaeus monodon in Iloilo, Philippines were monitored over two months for water quality and shrimp survival. Water quality (water temperature, pH, salinity, dissolved oxygen, and specific gravity) was not significantly different between the two hatcheries. However, the small hatchery seemed to favor survival of eggs to early postlarval stages, whereas the large hatchery favored the survival of late postlarvae. The normal microflora and bacterial loads of tiger shrimp eggs, larvae, postlarvae, and rearing water were determined to identify the dominant bacteria and potential pathogens. Shrimp eggs harbored the lowest heterotrophic bacterial counts. The counts increased from the nauplii to the mysis stages, decreased during the mysis stage, and then gradually increased in the older larvae. Bacterial loads in the rearing water reflected those in raw sea water and reservoir-aged sea water. Vibrio, Pseudomonas, and Aeromonas were not detected in eggs but were found in postlarvae. Ubiquitous in sea water, these bacteria increased with the build-up of organic matter. The bacterial load in the water adversely affected larval survival. Forty bacterial strains were isolated from tiger shrimp eggs, larvae, postlarvae, from the feeds, and from the rearing water. These were tested for biochemical characteristics and segregated into eight groups or genera. Six genera were found in the mysis and five genera in the postlarvae. The Vibrio species were dominant. Only Escherichia spp. were present in feeds, whereas five genera were present in the rearing water. Only Vibrio and Pseudomonas were present in both larvae and water. Moraxella, Aeromonas, and Klebsiella were found in larvae but not in rearing water. Micrococcus and coryneforms were found only in rearing water. Four Vibrio isolates were tested for virulence against shrimp postlarvae at inoculation densities of 102 and 107 cfu/ml. The four Vibrio species caused mortality of postlarvae, and more at the higher inoculation density. The most virulent was Vibrio anguillarum—30% of postlarvae died after 24 h exposure to a bacterial density of 102 cfu/ml, and all larvae died after 48 h at 107 cfu/ml. Shrimp hatcheries must have protocols for hygiene and sanitation and for disease prevention and control.
  • Book chapter

    Domestic effluents and pollution in Imbang River, Negros Occidental 

    GA Gonzales - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Domestic effluents, or waste waters from human settlements, were sampled from eight stations along Imbang River in Negros Occidental from July 1993 to February 1995. Three types of domestic waste waters were produced by communities along Imbang River. Waste waters from clothes washing, house cleaning, and bathing, including washings of domestic animals and holding pens and run-off from rains and storms were conveyed by open canals and ditches to the river. This type of domestic effluents were well aerated and had the least potential to degrade the rivers. Waste waters from kitchens and markets carried large volumes of food scraps and other solid wastes, were unsightly, and smelled bad from the decomposition of garbage. Overflows from septic tanks were the most objectionable domestic effluents with offensive visual and olfactory properties. Domestic effluents had pH 4–7.6, dissolved oxygen of 0.5–7.2 ppm, and biochemical oxygen demand ranging from 2 to 240 ppm. The overflows from septic tanks were of the worst quality, with BOD 20x greater than household washings, and 6x more than kitchen and market effluents. Fecal coliform bacteria made up 93% of the total coliforms in the septic tank overflows, 86% in kitchen and market waste waters, and 39% in household washings. The domestic effluents from the communities around Imbang River had higher than allowable levels of BOD and solids. The 11 barangays with 16,486 households and 85,535 people loaded about 3,4000 m3 of waste water into the river every day. Along with the waste water were 180 mt/yr of BOD, 590 mt/yr of total solids, plus large quantities of nutrients, surfactants, and fecal coliform bacteria.
  • Book chapter

    Households, agriculture, industry, fishing, and fish farming along Imbang River, Negros Occidental 

    RC Sanares - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Interviews were conducted among respondents identified from the households, agriculture farms, sugar mills, and fish farms along the whole stretch of Imbang River, Malisbog River, and Muyao Creek, down to Barangay Balaring at the coast of Silay City in Negros Occidental. Among the 1,073 households, 11% used river water for washing clothes, but 20% also used the rivers for disposal of waste waters, 11% for human wastes, and 13% for animal wastes. Among the 30 respondents from the agriculture sector, 70% discharged water into the river. The two sugar mills in the area treated waste waters partially before release into the rivers; one sugar mill also released wastes in a nearby rice field. Milling wastes such as bagasse, molasses, and mud press were reused and not dumped into the river. Imbang River was both the water source and wastewater sink for seven fish farms.
  • Book chapter

    Competitive and comparative advantages of brackishwater aquaculture of tiger shrimp, mud crab, and milkfish in the Philippines in 1985-1995 

    LA Gonzales, CD Elca, VA Gonzales, PA Alviola IV, FJ Paraguas & C Olalo - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    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:
    • Technology improvements in seed production from the hatchery of tiger shrimp, mud crab, and milkfish
    • Research and technologies for diagnosis, prevention, and control of diseases of tiger shrimp (e.g. luminous bacteria)
    • Training in farm management to enhance the skills of small-scale pond operators
    • 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
    • Market development to ensure sustainable outlets for brackishwater pond production
    • Reforms in trade and exchange rate policies to enhance global competitiveness
  • Book chapter

    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 

    TM Espino, RM Aspiras, NG Sabino, E Parreño, RL Macasadia & MLF del Mundo - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    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.
  • Book chapter

    Development of various value-added products from 'aloy' or bullet tuna Auxis rochei 

    EEM Santos-Yap - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    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.
  • Book chapter

    Growth and yield of the grouper Epinephelus coioides fed 'trash fish' at different rates and frequencies in floating net cages 

    GV Galzote & EC Abrera - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    The effects of various feeding rates and frequencies on the growth and survival of orangespotted grouper Epinephelus coides were determined in floating net cages in Tiniguiban Cove, Puerto Princesa, Palawan. Juveniles (average weight 60 g) were stocked in 2 m x 2 m x 1.5 m cages at a density of 10/m3. The experiment tested six treatments: 10% of body weight (BW) daily; 5% BW daily; ad libitum daily; 10% BW every other day; 5% BW every other day; and ad libitum every other day. After five months, the fish fed at 10% daily had 100% survival and the highest weight gain (520 g), growth rate (3.5 g/d), net production (31.44 kg), and gross income (P5,463). However, returns were negative in all treatments because of either too high feed consumption and poor conversion or low net production.
  • Book chapter

    Evaluation of fertilizer use and milkfish yields in Palawan 

    EB Dumada-ug & R Sevilleja - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Milkfish yields in Palawan in 1993–94 were low, only 595 kg/ha-yr on average and ranged 100–700 kg/ha-yr in 35 of 50 farms surveyed. Only seven farms had yields between 1,000 and 1,800 kg/ha-yr. Yields were higher in deeper ponds, and shallowness of ponds was a major constraint to high yields. Farm -gate prices of milkfish ranged from P25 to P55 and averaged P42. The prices of milkfish were on average 43x greater than the price of organic fertilizers (chicken manure) and 6x more than the price of inorganic fertilizers. The income from milkfish made up 10-95% and averaged 53% of the total income of the farmers. One crop cycle a year was the practice in 28 of the 50 farms; 20 farms had two crops, and two farms went for 3–4 crops a year. A crop cycle was 3–4 months long in 14 farms, 5–6 months in 29 farms, and 7–9 months in 7 farms. Crop cycles started with draining and drying the ponds and applying fertilizers to grow natural food. Most of the farms were supplied by tidal water and water exchange in the ponds was done every spring tide in 33 farms. The other farms changed water once a month, once or twice in a crop cycle, or once a year. Application rates of organic fertilizers were mostly less than 1 ton/ha-yr and averaged 515 kg/hayr, but three farms used as much as 1,250 kg/ha-yr, and one farm used 3,000 kg/ha-yr. Half as much inorganic fertilizers were used; the average for the 50 farms was only 211 kg/ha-yr, but one farm used as much as 1,350 kg/ha-yr. The fertilizers encouraged natural food to grow in the ponds. Two of the farms grew mostly plankton, 15 grew the benthic mat lablab, and 33 grew the green filamentous algae lumut. None of the farms used commercial feeds. Stocking rates varied widely among the farms, ranged from 1,000 to 60,000 fry or fingerlings per hectare per year and averaged 8,000/ ha-yr. Two-thirds of the farms stocked less than 7,000/ha-yr, but eight farms stocked fry or fingerlings at much higher rates of 13,000–60,000/ ha-yr. An input use variation model showed that milkfish yield was a function of the ratios of prices of milkfish to prices of organic and inorganic fertilizers; pond water depth and salinity; milkfish income as percent of total income; family size; membership in aquaculture association; and contacts with government‘s extension services and information dissemination system. The surveyed farms ranged from 3 to 40 years old, with 92% under 20 years; they had been in operation 1–23 years, 76% of them for less than eight years. Of the 50 farms in the survey, only nine were private (titled) lands, 34 were covered by fishpond lease agreements (FLA issued by the Bureau of Fisheries and Aquatic Resources), and the others had only survey documents or no papers at all. Farm sizes ranged 0.8–50 ha (average 12.5 ha), and 52% of them were smaller than 6 ha. The private farms were small, only 1–7 ha except one that was 25 ha. The FLA farms were much larger, and 23 of them were 5–50 ha. Large parts of the large farms were not operational, and 90% of the farms used effective areas of less than 7 ha. The low lease fees for FLAs evidently did not encourage farm development to increase yields. The farms had mostly shallow ponds 25–100 cm deep (average 68 cm).
  • Book chapter

    Yield and agar quality of three red seaweed Gracilaria species grown in tanks at three salinities 

    MSR Ferrer & AN Marasigan - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Gracilaria changii, G. firma and G. tenuistipitata were collected from the eastern coast of Sorsogon in southeastern Philippines and grown in concrete tanks at the SEAFDEC Aquaculture Department in Iloilo in May-June and in September-October 1994 at a stocking density of 1 kg/m2 and at three salinities (15, 25, and 35 ppt). In the first run, the highest specific growth rates per day were 2.5% at 25 ppt for G. changii, 3.6% at 35 ppt for G. firma, and 3.2% at 15 ppt for G. tenuistipitata. In the second run, the highest daily growth rates were 1.4% for G. changii, 1.2% for G. firma, and 3.3% for G. tenuistipitata, all at 15 ppt. Nutrient and light limitation in the second run led to lower and even negative growth rates. Gracilaria changii and G. firma were euryhaline but grew best at 25–35 ppt; G.tenuistipitata was not euryhaline and grew best at 15 ppt. The highest growth rates in tanks were at salinities close to those in the natural habitat: G. changii at 25 ppt, G. firma at 35 ppt, and G. tenuistipitata at 15 ppt. The estimated potential production (dry weight kg/m2-yr) in tanks was 1.65 kg G. changii at 25 ppt, 2.49 kg G. firma at 35 ppt, and 2.35 kg G. tenuistipitata at 15 ppt.

    Agar yields from three Gracilaria species varied from 5% to 23%, on average lowest in G. tenuistipitatata, and were generally higher at 25 ppt and 35 ppt than at 15 ppt. Agar gel strengths were also strongly affected by salinity and were highest at 35 ppt. Gracilaria tenuistipitata had very high gel strength (average 782 g/cm2 but as high as 1,082 g/cm2 comparable to agarose), well above the specified 750 g/cm2 for the international market. Gracilaria changii and G. firma had average gel strengths of 516 and 558 g/cm2, well within the range (400–600 g/cm2) for commercial agar used in the food industry. The sulfate contents were lower at 15 ppt and were even 0% in several instances, especially in G. tenuistipitata. The gelling temperature of 32°C and melting temperature of 97.3°C qualifies G. tenuistipitata for the international market. Gracilaria changii and G. firma had melting temperatures of 93–95°C but gelling temperatures of just 29°C. Farming techniques for these seaweeds should be developed to produce enough raw material for profitable commercial processing.
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    Transplantation, hatchery, and grow-out of window-pane oyster Placuna placenta in Guimaras and Iloilo 

    SS Garibay, SN Golez & AS Unggui - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    The windowpane oyster Placuna placenta (local name kapis) used to be harvested in large quantities and support a shellcraft industry in the Philippines, particularly in Panay Island. But the fishery and the industry declined markedly by the 1990s. Studies were conducted to transplant kapis and also to develop hatchery techniques for it in an effort to counter the population depletion. Kapis with average shell heights of 7 cm and 10 cm were transplanted from Roxas City in northern Panay Island and from Oton, Iloilo in southern Panay to Taklong Island in Guimaras during the rainy season (July–November) and the dry season (February–June). Survival of the transplants was higher during the dry season (57–60%) than during the rains (35–48%). Sexually mature kapis 10 cm in shell height were induced to spawn by temperature manipulation, water level manipulation, and use of ultravioletirradiated sea water. Spawning was successfully induced by raising the water temperature to 29±0.5oC. Eggs measured 45 μm on average, and fecundity was 5,000–10,000 per female. Kapis larvae were reared on a combination of the microalgae Isochrysis galbana, Tetraselmis sp., and Chaetoceros calcitrans, maintained at a density of 100,000 cells/ml. Three water treatment schemes were tested for larval rearing: chlorination, ultraviolet irradiation, and filtration (control). Larvae survived to the umbo veliger stage (180 μm, day 10) in chlorinated sea water whereas mass mortality occurred at the straight-hinge stage (days 4–) in both UV-treated and filtered sea water.
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    Demonstration of tilapia-carp polyculture in lowland and highland farms 

    AL Palma, RM Pol & AS Diamante - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    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.
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    Grow-out of milkfish in net-walled marine pens in La Union 

    ND Domenden - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    Grow-out of milkfish in 125 m2 net-walled marine pens was tested in Santo Tomas Cove, La Union at three stocking densities of 6, 9, and 12 fish/m2 and using commercial feed (crumbles and pellets) with 25–30% crude protein. After 115 days, survival of milkfish in marine pens was 92–97%. Fish stocked at 12/m2 or 1,500/pen grew to average weights of 286 g, larger than the fish stocked at lower densities. Feed conversion ratio was 2.3 at the highest density and worse at the lower densities. Costs and returns of milkfish grow-out in marine pens at three densities showed that feeds were the most costly component (55–69%) of production. The milkfish harvest was equivalent to about 33 mt/ha at the stocking of 120,000 fish/ha. Only at this high density was adequate profit made for a 48% return on investment per crop. Two crops are possible in the Ilocos region during the dry season from November to June. Grow-out of milkfish in marine pens can be improved if seed and feeds could be procured at lower cost.
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    Shrimp pond effluents and water quality in Imbang River, Negros Occidental 

    ET Taberna - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
    The contribution of shrimp farm effluents to the pollution load in Imbang River, Negros Occidental was measured during the period May 1993 to February 1995. Shrimp pond effluents were characterized and the pollution load estimated. The pond effluents had low average nitrite (0.0025 ppm) and nitrate (0.06 ppm) and optimum (for shrimp culture) pH 7.9, phosphate 0.15 ppm, dissolved oxygen 5.20 ppm, and salinity 23.3 ppt. Ammonia was 0.13 ppm on average in most farms, above the safe level for shrimp, and total suspended solids was 23 ppm, about 2.5x the allowed limit for effluents. Biochemical oxygen demand (20 ppm) and settleable solids (0.15 ppm) were still with acceptable limits. Residues of organochlorine pesticides were present at very low concentrations, well below the safe levels for aquatic life. Most of the pollution load came from the regular water exchanges over the 4-month crop cycle, at least every two weeks in low-density farms and more frequently in the high-density farms. The total draining of pond water at harvest contributed a minor load. Total solids from shrimp farms contributed a huge load, about 181,325 mt/yr. Total suspended solids contributed 1,285 mt/yr and settleable solids <1 mt/yr. The total BOD load was 154,367 kg/yr. The phosphate load was about 1,080 kg/yr, and the total nitrogen load was 1,225 kg/yr. The effects of effluent release from farms were localized. Upstream water quality and other uses of the river were not affected. Since most of the shrimp farms were located 1.5–2 km from the sea, the release of effluents during water exchange and at harvest did not adversely affect water quality downstream of these farms. Where such draining increased the levels of ammonia, phosphate, and total suspended solids in the river, the effect was significant only within 250 m from the release point, and the pollutants were dissipated about 550–800 m downstream The other water quality variables were at low levels in the pond effluents and did not affect the river water during draining. Often the concentrations of pollutants in the river were higher before than during draining of pond effluents. Stations upstream of the release sites of pond effluents often had high pollutant concentrations from other upstream sources.

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