Now showing items 3163-3182 of 3209

    • Article

      Water hardness determination using local laundry bar soaps for carp hatcheries. 

      JM Ferriols-Pavico, EV Aralar & AC Gonzal - Fisheries Research Journal of the Philippines, 1988 - Fisheries Research Society of the Philippines
      A simple method using local laundry soap is described for carp hatchery operation. A saturated soap solution was prepared and uses to titrate a 100-ml water sample of known hardness until a permanent lather appeared on the surface of the sample. The volume of soap solution was recorded to correspond to the hardness level tested. A fish farmer’s guide on the approximate levels of water hardness using WHEEL or PERLA soap solution is provided.
    • Article

      Water quality and holding capacity of intensive and semi-intensive milkfish (Chanos chanos) ponds 

      NS Sumagaysay-Chavoso & ML San Diego-McGlone - Aquaculture, 2003 - Elsevier
      This study determined the holding capacity of semi-intensive and intensive milkfish ponds and water quality in relation to fish biomass and feed input. Six units of 1000 m2 brackishwater ponds were used, three ponds for intensive system (20,000 fish ha−1) and three for semi-intensive system (8000 fish ha−1). Average production was significantly higher in intensive pond (3652 kg ha−1) than in semi-intensive pond (1352 kg ha−1) after a desired marketable size of fish was reached. Highest concentrations in effluents (mg l−1) of rearing water measured every 2 weeks were 0.369 and 0.289 for chlorophyll a (chl a), 0.485 and 0.512 for PO4–P, 0.279 and 0.811 for TAN, 0.094 and 0.082 for NO2–N, and 14.040 and 8.649 for NO3–N, 216 and 142 for total suspended solids (TSS), 15.0 and 21.7 for biological oxygen demand (BOD), in intensive and semi-intensive ponds, respectively. Lowest morning dissolved oxygen (DO) in intensive pond was 2.2 mg l−1, and did not decrease further because of aeration. In unaerated, semi-intensive pond, morning DO ranged from 1.3 to 5.0 mg l−1 but occasionally went below 1.0 mg l−1 resulting to fish mortalities at biomass of 835, 1206, and 1489 kg ha−1. Levels of NO3–N and dissolved inorganic N are linear functions of fish biomass or feed input in all systems (P<0.05). The buildup of nutrients is more pronounced at biomass of 1610 kg ha−1 and above while nutrient transformation (conversion of PO4–P or TAN to phytoplankton or vice versa) is apparent at biomass below 1419 kg ha−1. The holding capacity of unaerated, semi-intensive pond is below 1348 kg ha−1 or 54 kg feed ha−1 day−1 based on DO concentration of less than 1.0 mg l−1. However, the holding capacity can be lower than 835 kg ha−1 or 33 kg feed ha−1 day−1 during very calm weather or during rainy days when water column is stratified. Based on the results of regression analysis, the holding capacity of intensive pond should be set below 5107 kg ha−1 or 110 kg feed ha−1 day−1 so as not to exceed the acceptable levels for water quality variables in effluent waters.
    • Conference paper

      Water quality assessment of the Langat River, Selangor, Malaysia using the natural algal periphyton community and laboratory bioassays of two Chlorella species 

      A Anton - In IJ Dogma Jr., GC Trono Jr. & RA Tabbada (Eds.), Culture and use of algae in Southeast Asia. Proceedings of the Symposium on Culture and Utilization of Algae in Southeast Asia, 8-11 December 1981, Tigbauan, Iloilo, Philippines, 1990 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The physico-chemical conditions in 10 sampling stations off the headwaters of the Langat River, Selangor, Malaysia were studied. Monitoring was done twice a month from June to December 1980. Changes in water quality were observed downstream. A total of 35 taxa of periphyton in four main divisions of algae were identified. The decrease in the number of species in downstream stations could be due to changes in the river rather than to chemical pollution. Two species of Chlorella , namely, C. pyrenoidosa and C. vulgaris , were grown in filtered river water obtained from the different sampling stations to assess their growth responses. Results suggest that pollution in the Langat River was caused mainly by heavy siltation rather than chemical pollutants.
    • Oral presentation

      Water quality criteria for farming the grass shrimp, Penaeus monodon. 

      HC Chen - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Physiological and growth effects of pH, salinity, temperature, heavy metals, pesticides and others on juvenile grass shrimp Penaeus monodon have been investigated to

      determine the biologically safe concentrations. Optimal pH, salinity and temperature are found to be in the range of 8.0-8.5, 15-25 ppt, and 28-33°C, respectively. A dissolved oxygen concentration of 3.7 ppm seems to be the critical oxygen pressure to support the normal life of grass shrimp. To avoid poor survival and retarded growth, the recommended level for each pollutant are: heavy metals, 0.0025 ppm Hg, 0.1 ppm Cu, 0.15 ppm Cd, 0.25 ppm Zn; pesticides, 0.0004 ppb parathion, 0.001 ppb malathion, 0.008 ppb rotenone, 0.01 ppb Azodrin, 0.033 ppb Saturn, 0.01 ppb paraquat, 0.01 ppb Endosulfan, 1 ppb Butachlor; surfactants, 0.1 ppm Dunall OSE, 0.2 ppm BP 1100, 0.5 ppm Seagreen 805; and others, 0.033 ppm H2S, 0.1 ppm NH3.
    • 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.
    • Article

      The way forward with ecosystem-based management in tropical contexts: Reconciling with existing management systems 

      This paper discusses some of the challenges and opportunities that can arise when implementing ecosystem-basedmanagement (EBM) in tropical nations. EBM creates a new series of challenges, problems, and opportunities that must be considered in light of existing governance and management frameworks in a local context. The paper presents five case studies from different parts of the tropical world, including Oceania, insular and continental Southeast Asia, East Africa, and the Caribbean, which illustrate that the implementation of EBM in watershed and marine ecosystems offers a new series of challenges and opportunities for its inclusion with existing forms of environmental governance and management. The paper suggests that EBM is best thought of as an expansion of customary management (CM) and integrated coastal management (ICM), rather than a paradigm shift, and that it has certain benefits that are worth integrating into existing systems when possible. The paper concludes that the cultural and institutional context of CM as well as the experience, technical skills, and legal basis that serve ICM programs are logical platforms from which to build EBM programs. Some guidelines for creating hybrid management regimes are suggested. In sum, declining marine species and ecosystems require urgent action, necessitating utilization of existing paradigms such as ICM and CM as a foundation for building EBM.
    • Article

      Weaning of hatchery-bred milkfish larvae from live food to artificial diets 

      M Duray & T Bagarinao - Aquaculture, 1984 - Elsevier
      Two-week old milkfish (Chanos chanos ) larvae (7.5 mm standard length, 2.3 mg wet body weight) previously fed only rotifers were weaned abruptly to six artificial diets (commercial feed TP, artificial plankton AS and BP, experimental SEAFDEC diets CT and CB, and moist egg diet) with control larvae fed Artemia nauplii. Survival rates ranged from 38% on moist egg diet to 63% on BP, with 42% in the control. On day 43, larvae attained mean lengths of 7.7 mm on moist egg diet to 13.4 mm on Artemia , with no significant differences between diets. The mean wet weights were highest in larvae fed Artemia (77.8 mg). Results show the feasibility of weaning (gradually) even younger milk-fish larvae in hatcheries, using artificial diets.
    • Conference paper

      Weaning of the Asian catfish, Clarias macrocephalus Gunther, larvae to formulated dry diet 

      AC Fermin & MEC Bolivar - 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Two feeding trials lasting 10 days each were conducted to determine the weaning time in the Asian catfish, Clarias macrocephalus, larvae to dry diet feeding. Three-day-old catfish larvae were fed newly-hatched Artemia nauplii for 2,4, and 6 days after which ad libitum feeding with a commercial feed (trial 1) or a formulated diet (trial 2) was started. Fish fed exclusively dry diet (0-day Artemia feeding) or those fed only Artemia for 10 days served as the controls. In trial 1, fish fed Artemia at different durations had significantly higher growth and survival than those reared exclusively on dry diet. In trial 2, percent survival was not significantly different among fish with or without Artemia pre-feeding. However, fish had significantly higher final body weight and SGR when reared initially on Artemia prior to dry diet than those fed exclusively dry diet. Based on the results, catfish larvae can be successfully weaned to dry diet after feeding Artemia for a maximum period of four days (ave. BW=12.25 mg).
    • Technical Report

      Weather observation at Tigbauan, Iloilo, Philippines from 1977 to 1980 

      H Motoh, N Solis, E Caligdong, M Gelangre & F Boblo - 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Technical report / SEAFDEC. Aquaculture Department ; no. 8
      The observations include: (1) air and sea water temperatures; (2) cloud cover; (3) rainfall; (4) wind direction and speed; (5) salinity; (6) sea wave condition.
    • magazineArticle

      What are mangroves? 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1995 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The article presents about mangroves and its value to the ecosystem. The different species in the Philippines and mangroves coping mechanisms to the environment are also presented.
    • magazineArticle

      What are the latest developments in marine hatchery? 

      AJ Españo - SEAFDEC Asian Aquaculture, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      What crab is it? 

      RY Buendia - SEAFDEC Asian Aquaculture, 1999 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      What do you know about siganids? 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1994 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      What needs to be done?: Guide in mangrove reforestation 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The article presents a two-part guideline in mangrove reforestation. The first part is zonation, which is the process of determining what species are particularly suited to plant in a particular site. While, plantation establishment is the second part, it includes guides in the identification of species, selection of planting site, preparation of the planting sites, seed collection, handling and transporting of seeds, and planting.
    • magazineArticle

      What species [of snappers] are marketed? 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1992 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      What you need to know about sea bass and sea bass farming 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1988 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      What you should know about carp: its origin, varieties, physical appearance, feeding habits 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The article discusses the different varieties of carps, their origin, physical appearance and feeding habits. The species discussed were grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigala, and common carp (Cyprinus carpio).
    • magazineArticle

      What you should know about seaweeds 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1991 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Flyer

      What's in a tangab? 

      Anon. - 2008 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The flyer contains information about the tangab, which are large fixed filter nets held open by coconut trunks driven into the sea bed, and are operated in Iloilo Strait between Panay Island and Guimaras Island.
    • magazineArticle

      What's up on carp? 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Bighead carp is preferred among other species for culture because of its fast growth and high survival rate. Pen and cage culture of carps in Laguna de Bay is sustained by the availability of juveniles as a result of improved hatchery technology. Southeast Asian Fisheries Development Center and the Bureau of Fisheries and Aquatic Resources have been conducting research programs to enhance the carp culture industry in the country.