Now showing items 122-141 of 1070

    • Article

      Comparison of various water replenishment and fertilization schemes in brackishwater milkfish ponds 

      I Bombeo-Tuburan - Journal of Applied Ichthyology, 1989 - Blackwell Publishing
      The study was undertaken to determine the optimum combination of the frequency of water replenishment and fertilization that can yield the highest growth, survival, and gross production of milkfish. Results indicated that mean body weight and survival were not significantly different (P > 0.05) among the treatments. Gross fish production was higher in biweekly fertilization if considered as a single factor. However, when this was in combination with the weekly or biweekly water replenishment, similar gross fish production was attained. In any case, because biweekly fertilization has a better effect than a weekly schedule, the former should be used in combination with any other level of replenishment. A weekly water replenishment, however, is impractical in big pond areas of 5–10 ha compartments which are still common in some milkfish ponds in the Philippines. Therefore, biweekly water replenishment and fertilization with 16–20–0 at 50 kg ha-1 would be reasonable.
    • Article

      Contribution of natural food and supplemental feed to the gut content of Penaeus monodon Fabricius in a semi-intensive pond system in the Philippines 

      U Focken, A Groth, RM Coloso & K Becker - Aquaculture, 1998 - Elsevier
      Juvenile Penaeus monodon were stocked in grow-out ponds and fed a compound diet at high rates for 19 weeks under semi-intensive conditions. At three stages of the rearing period (weeks 6, 11 and 16), the gut content of the shrimp was analysed microscopically at every hour of the day. Additionally, possible sources of natural food (lablab, lumut, zoobenthos, etc.) were analysed microscopically and where possible for proximate composition. At week 6, the gut content consisted of 28.9% supplemental feed, 42.3% plant materials (other than from the pelleted diet), 1.8% crustacean parts and 27.0% diverse detrital matter. For week 11, the percentages (same order) were 47.5%, 21.1%, 22.8%, 8.6% and for week 16, 21.7%, 34.3%, 31.7% and 12.9%, respectively. Food preference did not change with time of the day. At week 6, most feeding activity occurred at night, later, feeding activity shifted to day-time. Reduction of the maximum gut content at dissolved oxygen levels below 4 mg l−1 at night indicated a cessation of feeding in which case shrimp fed during the day-time, when dissolved oxygen levels were higher.
    • Article

      Controlled release of testosterone and estradiol-17 β from biodegradable cylinders 

      X Zhang, UP Wyss, D Pichora, MFA Goosen, A Gonzal & CL Marte - Journal of Controlled Release, 1994 - Controlled Release Society
      A controlled release device for the hormones, testosterone and estradiol-17 β, was developed by coating a melt extruded hormone/poly (ϵ-caprolactone) cylinder with pure polylactide. Since testosterone and estradiol-17β have much higher permeabilities in poly (ϵ-caprolactone) than in polylactide, they primarily permeate through the open ends of the cylinder, with little release through the polylactide wall. By changing the cylinder length, the release rate and duration could be adjusted. The release followed Pick's diffusion equation for a drug loading below its solubility in poly (ϵ-caprolactone) or Higuchi's equation for a drug loading above the solubility. The diffusion coefficients of testosterone and estradiol-17β in poly (ϵ-caprolactone) were estimated as (8.31 ±3.12) × 10−18 and (0.728 ± 0.250) × 10−18 cm2/s, respectively.
    • Article

      The coral communities of Mararison Island, Culasi, Antique, Philippines 

      CL Marte & YP Tirol - UPV Journal of Natural Sciences, 2006 - University of the Philippines in the Visayas
      An assessment of the extensive fringing reefs surrounding Mararison lsland, Culasi, Antique was undertaken in 1994 to 1996 and in 1998 to provide scientific basis for management and enhancement of the island s resources as part of the Community Fisheries Resource Management project launched in 1991. The fringing reefs on the northwest side of the island are characterized by high percent coral cover (53-65%) consisting of very diverse coral species. The dominant forms are branching non-Acropora,with numerous small colonies of other coral forms. In contrast, the southeast side of the island fronting the fishing village is depau perate (4.7 -17.6% coral cover) with few small colonies of encrusting and massive corals characteristic of stressed reefs. However, highest coral cover consisting of dense stands of branching Acropora interspersed with branching non-Acropora was observed along the reef slope of Nablag station located at the western end of the island. Coral cover in the offshore reef (Guiob) was relatively fair (24%-46%). A total of 166 scleractinian corals were seen although only few species occurred frequently or provided high percent coral cover. Following the bleaching event of 1998, dramatic decreases (30%-61%) in live coral cover, particularly along the reef slopes, were observed in all stations.
    • Article

      The coral reef fisheries of Malalison Island, west central Philippines two years after fish sanctuary protection 

      YH Primavera - UPV Journal of Natural Science, 2002 - University of the Philippines in the Visayas
      Fish landings in Malalison Island, west central Philippines were monitored from June 1995 to January 1997 to determine species composition of catch, catch per unit effort (CPUE) and yield from the different fishing areas. A total of 596 fishing operations were recorded from the five fishing areas namely Nablag, Balabago and Salangan patch reefs and North and South fringing reefs. CPUE (kg fisher-1 hr-1) was 0.71 for hook and line, 1.16 for speargun, 2.80 for hookah (speargun with compressor), 1.29 for set gill net, 1.30 for drive-in gill net and 2.23 for drift gill net. Total fish yield was estimated to be 26.4 t km-2 yr-1. Reef and reef-associated fish species comprised about 85% of the total yield and was dominated by caesionids (33%) and acanthurids (28%) caught by hookah and set gill net. Hookah contributed highest yield from Nablag patch reef. Reef and reef-associated fish yield was estimated to be 22.44 t km-2 yr-1. This is almost four times the 1992 estimate of 5.8 t km-2 yr-1 when community-based management efforts were initiated by the SEAFDEC Aquaculture Department to sustain the coral reef fisheries in Malalison Island.
    • Article

      Cortisol stimulates the size and number of mitochondrion-rich cells in the yolk-sac membrane of embryos and larvae of tilapia (Oreochromis mossambicus) in vitro and in vivo 

      FG Ayson, T Kaneko, S Hasegawa & T Hirano - Journal of Experimental Zoology, 1995 - John Wiley and Sons
      The effect of cortisol and thyroid hormones on the activity of mitochondrion-rich (MR) cells in the yolk-sac membrane of tilapia (Oreochromis mossambicus) embryos and larvae was investigated. MR cells were identified by the fluorescent mitochondrial stain DASPEI. Yolk-sac membranes from 4-day-old embryos in fresh water (FW) were incubated for 24 h in medium supplemented with cortisol, thyroxine (T4), or triiodothyronine (T3). Treatment with cortisol at 0.1 μ/ml and higher significantly increased the population of MR cells and the intensity of fluorescence compared with the control, whereas MR cell size was not affected. Treatments with T4 and T3 did not affect MR cell density, size, or intensity of fluorescence.

      Four-day-old embryos in FW were immersed for 10 days in FW supplemented with cortisol, T4, or T3. A significant increase in MR cell size was observed starting on day 3 after treatment with 100 μ/ml cortisol. Treatment with lower doses of cortisol produced increases in the cell size on later days. Density of MR cells was significantly increased only on day 9. Treatment with T4 produced inconsistent results. Treatment with T3 did not affect MR cell size or density at any time. None of the three hormones affected the intensity of fluorescence of MR cells. The stimulatory activity of cortisol on MR cells in the yolk-sac membrane suggests that cortisol, present in the yolk of tilapia embryos and larvae, may be involved in osmoregulation during the early life stages of fish.
    • Article

      Critical factors influencing survival and hatching of milkfish (Chanos chanos Forsskal) eggs during simulated transport 

      LMB Garcia & JD Toledo - Aquaculture, 1988 - Elsevier
      The effects of loading density, length of transit time, temperature and salinity on milkfish (Chanos chanos Forsskal) eggs during simulated transport were examined. Rocking motion approximating conditions of transport of eggs collected from milkfish broodstock floating net cages to a hatchery was simulated using a laboratory orbit shaker. Loading densities of more than 7000 eggs/l in shipping bags resulted in decreased rates of survival and correspondingly lower hatching rates. Prolonged shaking simulating extended periods of egg transport also resulted in low egg survival and hatching rates compared to fertilized eggs not subjected to simulated transport. Egg survival after simulated transport at 20°C was lower than at 28°C, except at 20 ppt salinity, where survival was equal. Egg survival at 20°C progressively increased with declining salinity levels whereas high egg survival rates were observed after 2 h of simulated egg transport at 28°C and at the three salinities tested. Hatching rates of fertilized eggs after simulated transport were higher at 28°C than at 20°C regardless of salinity. Neither salinity nor its interaction with temperature affected hatching rates of eggs after simulated transport. These results indicate that survival and hatching of fertilized milkfish eggs after simulated transport is influenced by loading density, transport time, temperature and, to some degree, the salinity of the water. Based on these results, guidelines for handling and transporting milkfish eggs are given.
    • Article

      A critical review of shrimp pond culture in the Philippines 

      JH Primavera - Reviews in Fisheries Science, 1993 - Taylor & Francis
      The paper reviews and evaluates shrimp pond culture in the Philippines and its ecological and socioeconomic effects. The intertwined histories of the country's mangrove forests and culture ponds are treated in depth; brackishwater aquaculture and the different shrimp culture systems are described. Intensive farming is discussed in terms of feed and water requirements, chemical inputs and waste production, and the attendant organic and nutrient overloading, longevity and toxicity of chemicals, development of antibiotic resistance, and introduction of exotic species. Most of the discussion is based on the Philippine experience, but relevant case studies from other shrimp‐growing countries, notably Thailand and Indonesia, and also from salmon cage culture in the temperate zone, are included.

      Ecologically and economically more viable, semi‐intensive culture is recommended as the key to the long‐term sustainability of the shrimp industry. Because the greatest impact of brackishwater pond culture (including shrimp farming) is the loss of mangrove habitats and their varied goods and services, massive reforestation of degraded areas should be undertaken. Other recommendations are the promotion of environmentally sound aquaculture technologies, e.g., seaweed and mollusc culture and the integrated forestry‐aquaculture‐fisheries management of mangrove plantations (tumpang sari) in coastal areas; enforcement of existing laws that protect remaining mangroves; and promulgation of new laws to regulate water use and waste disposal. Areas for future research include the prevention and control of pond wastes and shrimp diseases, and refinements of the Indonesian tumpang sari for adoption locally.
    • Article

      Cryopreservation of different strains of the euryhaline rotifer Brachionus plicatilis embryos 

      JD Toledo, H Kurokura & H Nakagawa - Nippon Suisan Gakkaishi, 1991 - Japanese Society of Fisheries Science
      Cryopreserevation of different strains of Brachionus plicatilis symmetrical stage embryos was conducted. One S-type strain, namely Yashima-S (YS), and three L-type strains, namely Yashima-L (YL), Nagasaki (NG), and Hamana (HA), were used. Symmetrical stage embryos in 10% DMSO-28‰ sea water solution were frozen at -196°C using a two-step freezing procedure; the embryos were first cooled slowly from -5°C to -20°C at a rate of 0.3°C/min and then cooled rapidly by direct transfer to liquid nitrogen. Frozen samples were thawed in a gently stirred water bath at room temperature.

      A mean survival rate of 36% after 30 days storage in liquid nitrogen of HA strain was significantly lower than YS (55%), YL (58%), and NG (54%), and is due likely to its relatively larger embryo volume. There was no significant difference in the intrinsic rate of increase (r) between strains among clones taken from the cryopreservation or unfrozen control group. The results also indicate that various strains of B. plicatilis embryos can be cryopreserve without seriously altering their reproductive capability. The freezing method described could be of great potential in aquaculture and in future studies on rotifer genetics.
    • Article

      Cryopreservation of the euryhaline rotifer Brachionus plicatilis embryos 

      JD Toledo & H Kurokura - Aquaculture, 1990 - Elsevier
      A method for the separation and cryopreservation of Brachionus plicatilis embryos is described. Juveniles with uniform development were collected from a cultured stock by passing them through a series of nets. Collected juveniles were cultured and the embryos separated by vigorous vortex mixing as soon as the majority had laid their first eggs. Separated embryos at stage I (cleavage stage), stage II (invagination stage), stage III (symmetrical embryo stage), or stage IV (“eyed” stage) were frozen to −196°C using various concentrations of DMSO and a two-step freezing procedure. No stage I embryos survived freezing and the highest post-thaw survival was obtained with stage III embryos. A DMSO concentration of 10% of the freezing medium resulted in high post-thaw survival while concentrations higher than 10% appeared to be harmful to embryos. Prolonged incubation in 10% DMSO for up to 30 min before freezing increased post-thaw survival.

      Incorporating the above results, stage III embryos from a single batch culture were incubated in 10% DMSO for 30 min and frozen to −196°C. Post-thaw survival rates of 63%, 62%, 53%, and 55% were obtained after 3, 7, 15, and 30 days of storage in liquid nitrogen, respectively. Survivors fed actively on marine chlorella and started to lay eggs 2–3 days after thawing.
    • Article

      Culture and economics of wild grouper (Epinephelus coioides) using three feed types in ponds 

      I Bombeo-Tuburan, EB Coniza, EM Rodriguez & RF Agbayani - Aquaculture, 2001 - Elsevier
      The performance of wild Epinephelus coioides juveniles was compared by feeding with live tilapia juveniles, fish by-catch, and formulated diet for 5 months in grow-out ponds. To minimize cannibalism, the groupers were graded into small (BW=24.9±7.3 g), medium (45.8±5.7 g), and large (84.1±30.0 g) size groups as block in a Randomized Complete Block Design (RCBD) and reared in nine 350-m2 ponds. To supply the tilapia juveniles, adult tilapia were grown 2 months prior to stocking of grouper at a rate of 15 tilapia/grouper. Grouper fed by-catch were significantly higher (P<0.01) than the other treatments in terms of final length and total production. The quality of by-catch could be gleaned by its efficient feed conversion ratio (FCR) of 1.0 (dry basis), significantly better (P<0.01) than the formulated diet that had an FCR of 2.8. Using by-catch, 47% of the harvest weighed >400 g and only 14% was classified <200 g. The cost of juvenile grouper and feeds represented 88–89% of the total investment in all treatments. Economic sensitivity analysis showed that a combination of improvement in factors such as price of grouper juveniles, feeds, yield, survival, and FCR would result in higher return-on-investment (ROI). When cost and returns were considered, feeding juveniles with by-catch was more profitable because it resulted in net income of Php 361,623/ha/year, an ROI of 155%, and a payback period of 0.4 year. The results clearly show that these economic indicators appear to be attractive, thus making grouper pond culture using by-catch a viable industry. More research efforts should, however, be directed towards developing a cost-effective formulated diet for the grow-out culture of E. coioides.
    • Article

      Culture experiments on the harpacticoid copepod, Tisbintra elongata Mori, and evaluation of that species as a food organism for milkfish larvae 

      S Yamasaki & JT Canto Jr. - Memoirs of Faculty of Fisheries Kagoshima University, 1980 - Faculty of Fisheries, Kagoshima University
      The mass culture of the harpacticoid copepod, Tisbintra elongata, indigenous to Panay Island were conducted, feeding them on several kinds of food materials. Salinity tolerance as physiological parameter was also examined. At the same time their efficiency as food for milkfish larvae was evaluated.

      The highest density of 10.5 individuals/m/ was obtained in copepods fed on rice bran and fermented fish solubles at rates of 0.125 to 0.25 and 0.16 mg/indiv./day respectively. The provision of shelter as habitat was also supplementary for growth. This species of copepod was found to be euryhaline, and could grow to high densities in waters hypersaline to their natural habitat.

      Statistically, no significant difference of growth was observed between the milkfish larvae fed on this species and Artemia nauplius. However, comparatively stable results were obtained using Tisbintra as food. In this rearing of milkfish larvae, those larvae whose sizewas 12.3 to 13.5mm in body length were considered to be just prior to morphological change.
    • Article

      Culture of Artemia on rice bran: The conversion of a waste-product into highly nutritive animal protein 

      The age-old problem of finding a cheap suitable food for Artemia is finally solved with rice bran, in fact a waste-product which is available at a very low price in many countries all over the world.
    • Article

      Culture of finfish in netcages 

      DD Baliao, MA De los Santos & NM Franco - Aquaculture Engineering, 1998 - Society of Aquaculture Engineers of the Philippines, Inc.
      This report consists of two parts, the first deals on the cage culture of grouper, and the second on cage culture of tilapia. The culture of groupers is done in netcages set in marine waters, while tilapia is raised in netcages set in freshwater ponds, reservoirs or in lakes.
    • Article

      Culture of Macrobrachium rosenbergii (De Man 1879) in experimental cages in a freshwater eutrophic lake at different stocking densities 

      ML Cuvin-Aralar, EV Aralar, MA Laron & W Rosario - Aquaculture Research, 2007 - Blackwell Publishing
      Macrobrachium rosenbergii (de Man 1879) juveniles (0.4 g) were cultured in experimental cages (L × W × H: 2.5 × 1 × 1 m) in Laguna de Bay, the largest lake in the Philippines. The following stocking densities at four replicates each were used: 15, 30, 60 and 90 prawns m−2 of cage bottom. The mean sizes at harvest after 5 months of culture ranged from 14.3 g for the highest stocking density to 26.3 g for the lowest. The mean size at harvest, daily growth rate and size class distribution were significantly influenced by stocking density, with those at the lowest stocking density showing significantly better growth and overall proportion of larger prawns. Heterogeneous individual growth (HIG) was fairly evident in all treatments. The percentage of blue-clawed males was not influenced by treatment but the mean weight was significantly higher in the lower stocking densities. Both the percentage and mean weight of berried females were significantly higher in the lowest stocking density. Survival was the highest in the lower stocking densities (55.3%, 54.0%, 52.7% and 36.9% for 15, 30, 60 and 90 prawns m−2 respectively). Feed conversion ratio (FCR) improved with decreasing stocking density, ranging from 2.1 to 3. As expected, yield per cropping increased with stocking density and ranged from 450 to 1089 g m−2 yr−1 of actual cage area. Production values obtained in the cage cultured M. rosenbergii were comparable to or even higher than those reported from pond culture, given that the stocking densities used in this study were generally higher than in ponds. The results show that the farming of M. rosenbergii in cages in lakes is a viable alternative to pond culture and has the potential of improve aquaculture production in lakeshore fish farming communities.
    • Article

      Culture of Scylla serrata megalops in brackishwater ponds 

      EM Rodriguez, ET Quinitio, FD Parado-Estepa & OM Millamena - Asian Fisheries Science, 2001 - Asian Fisheries Society
      Three- to five-day old hatchery-reared megalops (4.0 to 6.4 mg body weight) of the mud crab, Scylla serrata, were cultured to the juvenile stage in 20 m2 net cages installed in brackishwater nursery ponds. To establish a suitable stocking density, megalops were stocked at 10, 20, and 30 ind·m-2 in net cages. Treatments were replicated three times over time. After 30 days of culture, mean survival of juveniles ranged from 48.3 to 53.3% and did not vary significantly (P > 0.05) among the three stocking densities. Similarly, the mean final body weights of juveniles ranging from 2.91 to 3.40 g and mass weights 458.9 to 1066 g did not significantly differ among stocking densities. These results show that stocking of crab megalops directly in net cages in a brackishwater pond is feasible at any of the stocking densities tested.
    • Web page

      Cultured Aquatic Species Information Programme - Scylla serrata (Forsskål, 1755) 

      Quinitio, Emilia T. - 2015 - Food and Agriculture Organization of the United Nations
    • Article

      Culturing seahorse (Hippocampus barbouri) in illuminated cages with supplementary Acetes feeding 

      LMB Garcia, GV Hilomen-Garcia & RLM Calibara - The Israeli Journal of Aquaculture-Bamidgeh, 2010 - The Society of Israeli Aquaculture and Marine Biotechnology (SIAMB)
      Juvenile Hippocampus barbouri were grown in illuminated cages with or without supplemental daytime feeding of thawed Acetes (a planktonic marine crustacean), or in non-illuminated cages with Acetes feeding, as a supplement to light-attracted zooplankton prey. After ten weeks, seahorses in illuminated cages fed Acetes had the highest mean body weight (2.24 g) and length (8.20 cm), but these did not significantly differ from seahorses in unfed illuminated cages (1.88 g; 7.25 cm), which did not significantly differ from those in fed non-illuminated cages (0.88 g; 6.32 cm). In all treatments, the mean instantaneous growth rate in body weight declined progressively throughout the test but the instantaneous growth rate in stretched length did not vary. Mean survival (76-100%) of seahorses in fed non-illuminated cages and in unfed illuminated cages did not vary significantly over the test period. The mean survival of seahorses in fed illuminated cages was lowest (54%), but did not significantly differ from the other treatments. Juvenile H. barbouri grown in illuminated cages had better growth than those in non-illuminated cages, but survival was reduced when seahorses in illuminated cages were fed Acetes.
    • Article

      The current state of aquaculture in Laguna de Bay 

      DC Israel - 2007 - Philippine Institute for Development Studies
      Series: PIDS Discussion Paper Series; No. 2007-20
      This paper presents some of the preliminary results and findings of an ongoing study, jointly conducted by the Southeast Asian Fisheries Development Center (SEAFDEC AQD) and Philippine Institute for Development Studies (PIDS), which assesses the current state of aquaculture in Laguna de Bay.

      The study uses primary and secondary data. The primary data were gathered through interviews with key informants and a cross-section survey of fishpen and fishcage operators and their operations in Laguna de Bay conducted in 2007. The secondary data were gathered from the published statistical indices of institutional sources and other relevant literature.

      The results of the study indicate that aquaculture in Laguna de Bay is a vibrant industry that includes not only fishpen and fishcage operators but also various participants in its input and product markets. Furthermore, they show that aquaculture contributes significantly to fish production in the lake as well as to national aquaculture and fisheries production.

      The results of the study also indicate that while aquaculture in Laguna de Bay has been an important economic contributor locally and nationally, it has been facing numerous problems over time that constrain its development. Of these, environment-related problems, lack of access to cheap capital, obstruction of navigational lanes by fishpens, existence of illegal fishpens, poaching and overall limited support from the government were considered very serious by aquaculture operators. These problems, therefore, may be the ones needing the most attention.
    • Article

      Cysteine concentration regulates cysteine metabolism to glutathione, sulfate and taurine in rat hepatocytes 

      MH Stipanuk, RM Coloso, RAG Garcia & MF Banks - Journal of Nutrition, 1992 - American Society for Nutrition
      The effect of cysteine concentration and cysteine source [cysteine, methionine or 2-oxo-thiazolidine-4-carboxylate (OTC)] on the metabolism of [35S]cysteine was studied in isolated rat hepatocytes. Production of each of the major metabolites of cysteine (glutathione, sulfate, taurine) increased as cysteine or methionine, but not OTC, concentration in the medium was increased. At equimolar exogenous substrate concentrations, cysteine availability to hepatocytes was greater from exogenous cysteine than from methionine, and that from methionine was greater than from OTC. The partitioning of cysteine, or the percentage of total metabolism resulting in production of each of the major metabolites, was markedly affected by cysteine concentration or availability. Low cysteine availability favored its utilization for glutathione; high cysteine availability favored its catabolism to sulfate and taurine. Under conditions of low cysteine availability (incubations with 0.2 mmol/L OTC), glutathione, sulfate and taurine production accounted for 90, 10 and 1%, respectively, of total metabolism. Under conditions of high cysteine availability (incubations with 1 mmol/L cysteine + bathocuproine disulfonate), glutathione, sulfate and taurine production accounted for 19, 47 and 34%, respectively, of total metabolism. Cysteine supplied as such and cysteine formed intracellularly from methionine were similarly partitioned. These studies demonstrate that methionine is not a superior substrate to cysteine for hepatic glutathione synthesis and that cysteine concentration (presumably intracellular cysteine concentration) has a major effect on the partitioning of cysteine sulfur to taurine in rat hepatocytes.