Now showing items 665-684 of 3211

    • Article

      Daily amount of rotifers taken by a sea bass Lates calcarifer larvae 

      H Kohno & M Duray - Philippine Journal of Science, 1990 - Science and Technology Information Institute
      The amount of rotifers consumed by a single sea bass Lates calcarifer larva per day (R) was examined by both the direct and by the satiation-digestion methods. In the direct method, R is estimated by the number of rotifers left in the larval tanks and larval density in the tanks, while in the satiation-digestion method R is estimated by the amount of rotifers found in the digestive tract of the larvae. In both methods, the amount of rotifers consumed by the larvae increased exponentially with larval growth. The relationship between the total length (TL) and the log-log plots of the maximum amount of rotifers eaten by a larva can be expressed by the following equations; R=1.799 x TL4.398 (r=0.975) for the direct method and R= 4.861 x TL3.432 (r = 0.907) for the satiation-digestion method. The relationship between TL and body wet weight (BW) can be expressed as: BW = 2.607 x 10-4 x TL3.786 (r=0.960) for larvae smaller than 6.5 mm TL and BW = 15.053 x 10-3 x TL2.855 (r = 0.916) for those larger than 6.5 mm TL.

      The index of satiation was almost the same for day 6(0-6), D-9 and D-12 (8.3-23%), higher range was observed in D-15 larvae. The index of daily feeding amount was comparatively higher in D-12 larvae compared to D-6, D-9 or D-15 larvae.
    • Article

      Daily rates of ingestion on rotifers and Artemia nauplii by laboratory-reared grouper larvae of Epinephelus suillus. 

      MN Duray - The Philippine Scientist, 1994 - San Carlos Publications, University of San Carlos
      The amount of rotifers and Artemia nauplii consumed daily by the grouper Epinephelus suillus larvae was determined through examination of gut contents. The larvae (2.6 mm TL) were initially fed rotifers on day 2 and newly hatched Artemia nauplii on day 21 (9.1 mm TL). The amount of food consumed by the larvae increased with larval growth. Larvae also showed diurnal feeding pattern at day 7 (3.6 mm TL), day 14 (4.9 mm TL), day 21 (9.1 mm TL) and day 28 (11.1 mm TL). Feeding incidence increased in the evening and became zero at 2100-2200 h. Active feeding started earlier in the older larvae and satiation was between 0900-1100 hr.
    • Article

      Daily variations in plasma hormone concentrations during the semilunar spawning cycle of the gulf killifish, Fundulus grandis 

      AC Emata, AH Meier & SM Hsiao - Journal of Experimental Zoology, 1991 - Wiley-Liss
      Male and female gulf killifish, Fundulus grandis, were kept in large cages submerged in their natural habitat in the Gulf of Mexico. Gonadosomatic indices (GSI: 100 × gonad weight/body weight) and blood samples were obtained from male and female fish every 4 hours (beginning at 1600) throughout a day on 3 separate days of the semilunar cycle: at the GSI and spawning peak (July 27–28), at midcycle (August 2–3), and on a day prior to the probable spawning peak (August 9–10). Blood samples of females were assayed for cortisol, estradiol-17β (E2), progesterone, testosterone, thyroxine (T4), and triiodothyronine (T3). The daily rhythms of hormones at each of the three days during the cycle differed markedly from one another. At the spawning peak, E2 and T3 peaks occurred at 1200, testosterone and progesterone peaks were found at 2400 and the GSI and cortisol peaks were at 0400. The GSI decreased sharply at 0800 indicating a period of probable spawning. At midcycle, most hormone levels were low throughout the day and the amplitudes of the hormone rhythms were suppressed. One day prior to the spawning peak, testosterone and progesterone variations (peaks at 2400) were similiar to those found on the day of the first semilunar GSI and spawning peaks. Daily variations of other hormones, especially E2, were prominent on the day prior to peak spawning but different from those found on the day of peak GSI/spawning. In males, plasma concentrations of cortisol, testosterone, T3 and T4 also underwent daily variations that differed from one another on the 3 days of the cycle. The results clearly demonstrate that there are dramatic changes in the daily variations of plasma hormone concentrations during the semilunar spawning cycle.
    • magazineArticle

      A dam and a tilapia farm-nursery 

      MB Surtida - SEAFDEC Asian Aquaculture, 1998 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Decapsulation of Artemia cysts: A simple technique for the improvement of the use of brine shrimp in aquaculture 

      P Sorgeloos, E Bossuyt, EM Laviña, M Baeza-Mesa & G Persoone - Aquaculture, 1977 - Elsevier
      Although it is a common practice in different disciplines of fundamental research on the brine shrimp, and despite the very interesting applications that it offers for the use of Artemia in aquaculture, the "decapsulation" technique, which removes the outer layer of the cyst shell of Artemia, is not known to shrimp and fish aquaculturists.

      The present paper describes the technology developed by the authors for the routine decapsulation of Artemia cysts. The advantages which result from the use of decapsulated cysts in aquacultural hatcheries are discussed.
    • Conference paper

      The decline of native fishes and fisheries and the rise of aquaculture in lakes and rivers in the Philippines 

      T Bagarinao - 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center; Philippine Council for Aquatic and Marine Research and Development; Bureau of Fisheries and Aquatic Resources
      This paper reviews historical and recent data on biodiversity, fisheries, exotic fishes, and aquaculture in Philippine lakes and rivers. The country's lakes and rivers are poor in primary freshwater fishes because the Philippines' only connection with the Asian mainland had been through land bridges between Borneo, the Sulu islands, Mindanao, Palawan and Mindoro - in which islands endemic carps have evolved. Philippine lakes and rivers instead have secondary freshwater fishes such as gobies, migratory marine fishes such as mullets, and some snails, clams, and prawns. Most lakes and rivers have been severely degraded and their biodiversity reduced by siltation, pollution, overfishing, and the establishment of exotic fishes from other countries or elsewhere in the country. Many fishes first described in the Philippines in 1910-1940 by Seale, Herre, and Filipino ichthyologists have not been collected in recent years. The Laguna de Bay fishery in the early 1960s was largely dependent on the 'ayungin' Therapon plumbeus, 'biyang puti' Glossogobius giurus, and the 'kanduli' Arius manilensis that together comprised 95% of the annual 83,000 mt; another 19,000 mt came from shrimps and 245,000 mt from snails. Fishing and snail-dredging were so intense that catches declined and the whole lake fishery collapsed around 1970. After the collapse, the primary production of the lake increased and milkfish and tilapia became natural choices for aquaculture. Lake Lanao became famous for its species flock of 18 endemic carps, but these are now extinct, except perhaps two species. In 1963, these carps contributed 981 mt to the fishery, other native fishes 269 mt, shrimps and snails 257 mt, and introduced fishes 479 mt. Twenty years later, endemic carps have made up only 92 mt, native fishes 141 mt, shrimps and snails 164 mt, and introduced fishes 312 mt of the harvest from the lake. The 'kadurog' G. giurus, probably stocked in the lake with milkfish larvae in 1955, proliferated in the 1960s and apparently drove the endemic carps to extinction. The 'katolong' Hypseleotris agilis was first seen in the lake in 1977 and has since outcompeted the 'kadurog'. In Lakes Taal and Naujan, migratory marine fishes have been caught by fish corrals set across the outlets, but the catch along Pansipit River has fallen since the turn of the century and that in Butas River fell from 62 mt in 1977 to 17 mt in 1983. Catches of the endemic sardine Harengula tawilis in Lake Taal fluctuated between 4,400 mt in 1983 to 11,300 mt in 1990 and 1,400 mt in 1994. Cage culture of tilapia and milkfish has been going on in Lake Taal for 10 years. In Lakes Buhi and Bato, the endemic 'sinarapan' Mistichthys luzonensis almost disappeared due to fine-net fishing and tilapia stocking; catches have been 50-90 mt in 1983-93 but zero in 1994.
    • Article

      Deep-sea farming of Kappaphycus using the multiple raft, long-line method 

      AQ Hurtado & RF Agbayani - Botanica Marina, 2002 - Walter de Gruyter
      Farming practices of Kappaphycus seaweed planters using the multiple raft, long-line method were assessed in three major cultivation areas of Zamboanga del Sur, Mindanao. Results show that this cultivation method is appropriate in deeper waters (> 10 m deep). Family labor (6–70 years old) is usually used in the selection and preparation of ‘cuttings’, unloading of newly harvested crops and drying of seaweeds, while preparation and installation of the raft, tying of ‘cuttings’ and harvesting, hired labor is needed. Though the multiple raft, long-line method of cultivating Kappaphycus is expensive (PhP 45,742 to PhP 49,785) based on a 500 m2 raft, return on investment (ROI) is high and the payback period is short. Of the three areas assessed, Maasin had the highest ROI (218%), followed by Tictauan Island (212%), and finally Taluksangay (79%). Consequently, the payback period followed the same order. Seaweed farming in these areas showed a tremendous impact on the quality life of the fisher folk and contributed a high revenue to the national economy.
    • Conference paper

      Defatted soybean meal and Leucaena leaf meal as protein sources in diets for Penaeus monodon juveniles 

      F Piedad-Pascual & M Catacutan - In R Hirano & I Hanyu (Eds.), The Second Asian Fisheries Forum: Proceedings of the Second Asian Fisheries Forum, Tokyo, Japan, 17 - 22 April 1989, 1990 - Asian Fisheries Society
      Penaeus monodon juveniles, mean weight 0.38 g, were fed 12 practical diets with 30, 20 or 16% Peruvian fish meal, 15 or 35% defatted soybean meal (DSM), 10% Leucaena leucocephala , leaf meal (LM), and 15% shrimp meal with and without vitamins and/or minerals. The diets contained 42-48% crude protein and 11-13% crude fat. The animals were stocked at 10 per fiberglass tank, and reared in 40 aerated seawater in a flowthrough system for 8 weeks. Growth and survival were not affected by the level of DSM but significantly decreased in prawn fed diets with LM. Feed conversion ratios of prawn were better for complete diets than those where vitamins only were added. Poor feed conversion ratios and specific growth rates were obtained when no vitamins and minerals or only minerals were added to the diets.
    • Conference paper

      Defects in the handling, storage and transport of mud crab 

      JP Peralta & DS Cheung - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Consumers prefer to buy live mud crabs (Scylla). Moribund and dead crabs have very low market value. Immediately after harvest, the crabs are tied to render their claws immobile. The time between harvest and arrival of crabs at the final destination is 3-5 days. During the holding and transport period, the crabs are no longer fed and are sometimes subjected to stressful conditions (e.g. high temperature) which may result to weight loss, muscle emaciation and other undesirable conditions of the crabs, and mortality. Likewise, ammoniacal odor (strong urine-like smell) that affects flavor is sometimes observed. Crabs with emaciated muscle and undesirable odor are considered rejects.

      This paper presents the initial results of the project on the Improvement in the Handling, Storage and Transport of Mud Crabs under Sub-program C entitled Improvement of Feeds and Stock Management Practices in Mud Crab Grow-out Culture under the National Mud Crab Science and Technology Program.
    • Article

      Dehalogenase from Methylobacterium sp. HJ1 induced by the herbicide 2, 2-dichloropropionate (Dalapon) 

      NH Jing, AM Taha, RV Pakingking Jr., RAB Wahab & F Huyop - African Journal of Microbiology Research, 2008 - Academic Journals
      Heavy industrial activities and agricultural processes require consumption of many halogenated compounds, and release them continuously as pollutants into the environment. These xenobiotics show high toxicity and persistence and cause many problems to the society, soils and ground water. Microbial dehalogenases are involved in the biodegradation of many important chlorinated compounds. A bacterial strain identified as Methylobacterium sp. HJ1 is able to degrade the herbicide 2,2-dichloropropionic acid by removal of the halogen and subsequent metabolism of the product for energy. D,L-2-chloropropionate also supported good growth of the organism but 3-chloropropionate, monochloroacetate and dichloroacetate were not utilized. Cell-free extracts of the 2,2-dichloropropionate-grown bacteria converted 2,2-dichloropropionate into pyruvate with the release of two chloride ions for each molecule of pyruvate formed. This indicates the presence of dehalogenase activity in the cell-free extracts. Only 2,2-dichloropropionate and D,L-2-chloropropionate were inducers and substrates for the dehalogenase. Monochloroacetate and dichloroacetate did not serve as an inducer, whereas 3-chloropropionate was a non-substrate inducer.
    • Book chapter

      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.
    • Article

      Density dependent growth of the tropical abalone Haliotis asinina in cage culture 

      EC Capinpin Jr., JD Toledo, VC Encena II & M Doi - Aquaculture, 1999 - Elsevier
      The effects of different stocking densities on the growth, feed conversion ratio and survival of two size groups of the tropical abalone Haliotis asinina were determined. Three culture trials were conducted in net cages installed in a sheltered cove, Guimaras Province, Philippines. Trials 1 and 2 were conducted using 15–20 mm abalone juveniles for 150 days, while trial 3 was conducted using 35–40 mm abalone for 180 days. The animals were fed sufficient amounts of the red alga, Gracilariopsis bailinae (=G. heteroclada), throughout the experiment. There was an inverse relationship between growth (length and weight) and stocking density. Feed conversion ratio was not influenced by density, but was observed to be higher for larger animals. Survival was not significantly affected by density. Net cages are appropriate for culture of H. asinina. This study showed that H. asinina can reach commercial size of about 60 mm in one year. It also showed that growth of H. asinina can be sustained on a single-species diet. An economic analysis will be important in choosing the best stocking density for commercial production.
    • Conference paper

      Depuration of Molluscs. 

      RQ Gacutan, ML Bulalacao & AT Vizcarra - In Status of Mollusc Resources and Prospects for Development. Proceedings of the Seminar-Workshop on Status of Mollusc Resources and Prospects for Development, Ecotech Center, Cebu City, May 2-3, 1986., 1987 - Philippine Council for Agriculture, Forestry and Natural Resources Research and Development; Bureau of Fisheries and Aquatic Resources
      The experimental system put up at SEAFDEC [Southeast Asian Fisheries Development Center; Philippines] consisted of six rectangular (96 x 196 x 42 cm) fiberglass-coated tanks made of marine plywood. It can depurate about 230 to 310 kg bivalves in two days. Initial findings showed that under normal seawater conditions (salinity 29-32 ppt, temperature 27-30 degrees Celsius; oxygen content 3-6.2 mg/L; and pH 7.4-8.3) and moderate rate of flow (7-10 L/min), highly contaminated oysters (MPN 1.0 x 10 to the fifth power to 2.0 x 10 to the sixth power/100 g meat) can be depurated within 48 hr or less. A short flume type of tank with a volume of about 250 L was designed, tested and showed to cleanse oysters under normal conditions in only 24 hr with a flow rate of 7L/min and with very little resulting mortality. More important, the tank can be lifted and moved by only two men of average body built.
    • Oral presentation

      Description of the embryonic stages of Penaeus notialis and the influence of some abiotic factors on the species. 

      I Fernandez & M Oliva - 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
      The embryonic development of the shrimp Penaeus notialis Farfante, 1967 is studied. The duration from spawning to hatching of the nauplii was 14-16 hr. As soon as spawning occurs, a sequence of transformations is observed in the characteristic cell mitosis up to the formation of the embryo which breaks the membrane and emerges as the first naupliar stage. The process of development is very similar to other penaeids and the duration of each stage is characteristic of the species. The influence of salinity and pH on spawning, hatching rate and survival, and the optimal values for each factor were determined.
    • Conference paper

      Design and construction of a fishpen for an aquaculture-based social laboratory. 

      VS Traviña - In Report of the National Consultative Meeting on Aquaculture Engineering, 2-5 October 1985, Tigbauan, Iloilo, Philippines, 1986 - ASEAN/UNDP/FAO Regional Small Scale Coastal Fisheries Development Project
      A pilot project for the pen culture of Tilapia nilotica and bighead carp in an irrigation canal was initiated in Barangay Cauayan, Pototan, Iloilo. The project, Cauayan Social Laboratory, involves cooperators from the community and other government agencies with the aim of improving the quality of life of the rural poor while at the same time increasing fish production through aquaculture.

      Three barrier nets that contain the fish stock were set across the irrigation canal at 30 m distance to provide two culture areas. Six days after completion and stocking, however, despite all maintenance efforts, these structures collapsed due to heavy fouling — an environmental factor that was not foreseen.

      Giving due regard to this phenomenon, a modified design was constructed with provision for free passage of potential foulers and general flotsam that may be discharged in the irrigation canal. In addition, considerations were also given to maintenance work, especially the cleaning of fouled wire and mesh nettings used to enclose the cultured stock.
    • Conference paper

      Design of proposed fish cages for Kaptai lake in Bangladesh 

      BC Cabangbang - In Proceedings of the International Workshop on Pen Cage Culture of Fish, 11-22 February 1979, Tigbauan, Iloilo, Philippines, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center; International Development Research Centre
      After a brief introduction dealing with the prospects of fish farming in cages in Kaptai Lake (Karnafuli Reservoir), a detailed description of a fish cage, which can be constructed by local fishermen, is given.
    • Book

      Design, operation and economics of a small-scale hatchery for the larval rearing of sugpo, Penaeus monodon Fab. 

      RR Platon - 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 1
      One of the major problems in the mass production of sugpo is how to obtain a constant supply of fry. Since ultimately it is the private sector which should produce the sugpo fry to fill the needs of the industry, the Barangay Hatchery Project under the Prawn Program of the Aquaculture Department of SEAFDEC has scaled down the hatchery technology from large tanks to a level which can be adopted by the private sector, especially in the villages, with a minimum of financial and technical inputs. This guide to small-scale hatchery operations is expected to generate more enthusiasm among fish farmers interested in venturing into sugpo culture.
    • Article

      Detection of Vibrio penaeicida in kuruma prawn after transport 

      LD de la Peña, H Koube, T Nakai & K Muroga - Fish Pathology, 1997 - Japanese Society of Fish Pathology
      In Japan, vibriosis caused by Vibrio penaeicida usually occurs in cultured kuruma prawn (Penaeus japonicus) during summer and fall. The causative bacterium can easily be detected from overtly diseased prawns, but from apparently healthy prawns the detection rate is low. The results of the conventional isolation method of the pathogen does not seem to reflect the true carrier rate because more prawns often come into overt infection after collection-transport-acclimation procedures, although such data have not been published.

      In the present study, transport stress was given to apparently healthy prawns to verify the above phenomenon.
    • Conference paper

      Detoxification of Pyrodinium-generated paralytic shellfish poisoning toxin in Perna viridis from Western Samar, Philippines 

      RQ Gacutan, MY Tabbu, MTR de Castro, AB Gallego, ML Bulalacao, L Arafiles & F Icatlo Jr. - In AW White, M Anraku & KK Hooi (Eds.), Toxic Red Tides and Shellfish Toxicity in Southeast Asia. Proceedings of a Consultative Meeting, 11-14 September 1984, Singapore, 1984 - SEAFDEC Marine Fisheries Research Department; International Development Research Centre
      The results are presented of procedures for the detoxification of paralytic shellfish poisoning toxin using ozone, chlorine and PVP-iodine. Findings indicate ozone and PVP-iodine to effectively inactivate the toxins isolated from Perna viridis ; however, further investigations are recommended.
    • magazineArticle

      Developing a specific pathogen-free shrimp: the case of IHHN virus 

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