Now showing items 21-40 of 125

    • Article

      Dietary crude protein requirement of Tilapia nilotica fry 

      CB Santiago, M Bañes-Aldaba & MA Laron - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      To determine growth and survival of Tilapia nilotica fry fed formulated practical dry diets with varying crude protein levels, fish were subjected to 3 seperate feeding trials. Isocaloric practical diets containing 20, 25, 30 and 35% crude protein were fed to fry at 15% fish biomass daily for 7 weeks in 2 trials and another set containing 20, 25, 30, 35, 40, 45 and 50% was given for 8 weeks. On the basis of growth, survival and feed conversion, T. nilotica fry required 35% crude protein in the practical diets given at 15% fish biomass.
    • Article

      Ecology and life history of penaeid shrimps 

      H Motoh, N Solis & E Caligdong - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Fourteen species of penaeid shrimps with commercial value in Batan Bay and Tigbauan-Guimbal waters were identified as follows: Penaeus monodon, P. semisulcatus, P. japonicus, Metapenaeus ensis, M. burkenroadi, M. endeavouri, Metapenaeopsis palmensis, M. stridulans, Trachypenaeus fulvus, and Parapenaeus longipes. Among the 14 penaeids, P. semisulcatus, M. ensis and M. palmensis were found to be the dominant species within each genus. There are seven existing fishing gears for shrimping in the Batan Bay and Tigbauan-Guimbal waters: fish corrals, lift net, filter net, gill net, skimming net, baby trawler and commercial trawler. In general, female penaeids are larger than males. The largest P. monodon female measured was 81 mm in carapace length with 23 g in body weight. The largest male measuring 59 mm in carapace length with 119 g of body weight was caught in Batan Bay. Judging from spermatozoa occurrence on both sexes of P. monodon, the biological minimum size for male is 37 mm in carapace length and 49 mm for female. A total of 133 Penaeus postlarvae obtained from the offshore were identified by comparison with those reared in the laboratory. The postlarvae of P. japonicus-latisulcatus complex were quite dominant (60.2%), followed by P. semisulcatus (18.0%), and P. merguiensis-indicus complex (17.3%). The number of P. monodon postlarvae was relatively small (4.5%). The modal carapace length of P. monodon postlarvae from the offshore was 1.3 mm with three or four dorsal and no ventral spines on the rostrum, while P. monodon fry from the shoreline had 2.3 mm with five or six dorsal and one or two ventral spines.
    • Article

      The effect of different binders on the water stability of feeds for prawn 

      F Piedad-Pascual, L Bandonil & WH Destajo - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Corn starch, gelatin, sago palm starch, agar, and bread flour were tested for their binding capacity in pelleted diets for Penaeus monodon . Agar was found to be good binder, but it costs too much, while bread flour was also good but as it's commonly used for human comsumption its use for animal feed should be minimized. The use of 20% bread flour, or a combination of 5% sago palm starch or corn starch with 15% bread flour is recommended, depending on the cost and availability. Basic composition of the formulated diet is tabulated, as is water stability of 2 and 4 mm diameter steamed pellets after 2, 6 and 18 h.
    • Article

      Effect of different feeding regimes on reproduction and survival of ablated Penaeus monodon Fabricius 

      JH Primavera, C Lim & E Borlongan - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Results of experiments conducted on ablated Penaeus monodon, fed with 4 different feeds (pellet-pellet, mussel-mussel, mussel-pellet and squid-pellet), on survival, spawning, fecundity and hatching rate are given and discussed.
    • Article

      Effect of different light intensities on the growth of the diatom Chaetoceros calcitrans 

      EC Jereos - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Batch cultures of C. calcitrans were maintained indoors at a temperature range of 21 to 25 C and continuously illuminated by 40-watt daylight fluorescent lights. Cultures were exposed to 5 different intensities from 200 to 25,000 lux. Population counts show that light intensity affects growth and reproduction of the algae cultivated. A comparison of population peak growths showed cultures illuminated by 12,000 lux to have higher cell counts than those exposed to higher or lower light intensities.
    • Article

      Effect of different sex ratios of ablated wild-stock Penaeus monodon Fabricius on maturation, fecundity and hatching rates 

      R Alava & JH Primavera - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Effect of feeding rate on the survival and growth of milkfish (Chanos chanos) fry in a controlled environment 

      C Lim - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The optimum daily feed allowance varies with species, age, size, frequency of feeding, culture procedures, quality of feed and water quality. This experiment indicated that with a diet containing 40% protein and 3,450 kcal of M.E. per kg, a feeding rate of 16-20% of the biomass is optimum for satisfactory survival and growth of fry raised in a controlled environment. Increasing the feeding level beyond this value was not beneficial but in turn increased the ammonia-nitrogen concentration to a level which is harmful to the fish.
    • Article

      Effect of furanace on the development of larval stages of Penaeus monodon Fabricius 

      RQ Gacutan & AT Llobrera - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Zoea 2 (Z2), Mysis 1 (M1) and Postlarva 1 (P1) of P. monodon artificially spawned in closed-system concrete hatchery tanks were bioassayed for their tolerance to the antibiotic furanace. The setup consisted of four 20-liter capacity plastic basins previously conditioned for 15 days with freshwater in full sunlight. During the experiment, each basin was filled with 5 liters of seawater to which was added filtered Chaetoceros and Brachionus to give densities of 5 . 0-7 . 5 x 10-4 cells/ml and 10-20 individuals/ml, respectively. The following are the properties of the water used throughout the experiments: salinity, 26-32%; pH, 7 . 3-8 . 4; temperature, 25-30 degree C; dissolved oxygen, 4 . 5-8 . 4 ppm; nitrite, 0 . 36-0 . 99 ppm; and ammonia, 0 . 10-0 . 30 ppm. To each basin were added 50 healthy larvae of specific stages of P. monodon. After an initial acclimation of one hour in the medium, preweighed amounts of the antibiotic were added and thoroughly dissolved. The concentrations tested were 1 . 0, 2 . 0 and 3 . 0 ppm. One basin always served as control. After 24 hours of exposure, the surviving population in each basin was counted. The survivors were then examined thoroughly under the microscope for unusual behavior and morphological defects brought about by the exposure. To minimize wide variations in the medium as a result of feeding and other manipulations, the systems were all prepared at 9:00 a.m. each time, and the feeds on two instances, one at 5:00 p.m. and another at 5:00 a.m. Fifteen trials conducted with Z2 showed survival ranges of 68% to 98% with a mean of 77 . 6% in the controls; 32% to 94% with a mean of 65 . 7% at 1 ppm, and 0% to 56% with a mean of 36.5% at 2 ppm. There were no survivors at 3 ppm. Interpolation from the survival-dose curve gave a 24-hr LC50 of approximately 1.6 ppm.
    • Article

      Effect of nitrite, ammonia, and temperature on P. monodon larvae 

      FF Catedral, DD Gerochi, AT Quibuyen & CM Casalmir - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      P. monodon larvae were studied for the effects of temperature, ammonia, and nitrite on survival. Toxicity levels of nitrite were found to vary with larval stage. Larvae could tolerate ammonia up to about 10 ppm, with the effect more clearly shown by the zoea stage. Survival and growth were not significantly affected by temperature, although moulting was enhanced at temperatures higher than 29°C. Larvae of P. monodon have lower tolerance toward nitrite and ammonia compared to postlarvae. Although high survival was obtained at low levels of nitrite and ammonia, it is still necessary to know their effects on metabolism, in order to examine possible biochemical parameters for diagnosing sublethal toxicity or stress.
    • Article

      Effect of some physico-chemical factors on the survival and growth of Penaeus monodon postlarvae 

      FF Catedral, R Coloso, N Valera, CM Casalmir & AT Quibuyen - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Growth and survival rates of P. monodon postlarvae were examined at different temperatures, salinities, and nitrite and ammonia concentrations, using one feed level. Condition of postlarvae greatly affected the experimental results shown in some instances where very low survival rates were obtained, even for the controls. Results indicated that postlarvae from P10 and up can tolerate salinity changes of 10 to 20 ppt without prior acclimation. Survival generally appears the same for temperatures between 24 and 36°C. It appears that P. monodon postlarvae have higher temperature tolerance. Tolerance of postlarvae at the early postlarval stage is between 30 and 50 ppm of nitrate. They were more tolerant from P10 upwards. Although survival was high in runs containing nitrite, growing appears to have been affected. Postlarvae could tolerate ammonia concentrations up to about 50 ppm. At 100 ppm higher mortality rates were observed. Whether or not there was any permanent effect by nitrate and ammonia at high but apparently tolerable levels is not known.
    • Article

      Effect of substrate types on fecundity and nauplii production of ablated Penaeus monodon Fabricius 

      R Pudadera, J Primavera & E Borlongan - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Experiments were undertaken to assess the survival, spawning, fecundity and nauplii production of ablated P. monodon females reared in flow-through broodstock tanks with white coralline and black sand substrate for 62 days. The similar trend observed in mortality rates in both substrates suggests that variation in substrate material for broodstock tanks is not a likely cause of prawn mortality. There were also no significant differences observed between rematurtion rates, i.e. number of spawnings, under the different treatments. Singnificantly higher nauplii production were observed in females in tanks with white substrates. At present, the land-based broodstock tanks in SEAFDEC utilize white coralline substrates due to higher hatching rate of eggs and nauplii production, convenience in siphoning out debris and excess food that tend to accumulte in the tank, and contrast provided by the white substrate during nightly observations of ovaries.
    • Article

      Effect of temperature on the oxygen consumption of Penaeus monodon postlarvae 

      FF Catedral & R Sayson - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Extended abstract only.
    • Article

      The effect of various protein levels on the growth and survival rates of Penaeus monodon Fabricius 

      A Khannapa - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Postlarvae of tiger prawns, P. monodon , were fed with various protein levels of 0; 30; 40 and 50%, fish meal and rice bran were combined and pelletized for 16 wks. Prawns used had an average mean length of 1.2 mm and an average mean weight of 5.5 mg. Nitrite, ammonia, dissolved oxygen content, temperature and pH were monitored. After one month of feeding, growth increments of postlarvae fed with 30% protein diet were significantly different from those given 0; 40 and 50%. Survival rate of the group fed 40% protein was higher (81.7%) but was not significantly different from those fed 30% (68.0%). The highest feed efficiency was obtained from the 30% protein pellets (4.6). At the end of 16 weeks, growth increment of 40% protein level was significantly different from the 30% and 50% protein levels, but the survival rate was not signficantly different from the 30% protein level. Feed conversion for the 40% protein diet was 2.8.
    • Article

      Effect of varying crude protein levels on spawning frequency and growth of Sarotherodon niloticus breeders 

      CB Santiago, M Bañes-Aldaba & MA Laron - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Four-month-old S. niloticus breeders were fed with dry pellets containing 20-50% crude protein and the frequency of spawning involving removal of egg from the mouthbrooding females and growth were determined. When the diets contain high quality proteins from fish meal and soybean oil meal and the amounts of daily food allowance are at satiation level, the influence of increasing dietary crude protein on spawning frequency involving egg removal from the brooder and growth may not be significant.
    • Article

      Effects of 2-phenoxy ethanol and MS-222 on milkfish fingerlings (Chanos chanos) as anaesthetic agents 

      T Murai & MR Catacutan - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      An experiment was undertaken in order to determine an adequate anaesthetic and optimum concentrations for use in the handling of fingerling milkfish (Chanos chanos). The compounds 2-phenoxy ethanol and MS-222 were investigated. Results show the latter to be adequate with optimum concentrations between 100 and 200 ppm.
    • Article

      Effects of crude, semipurified and purified starch of sago (Metroxylon sagu Rottb.) on the water stability of pelleted shrimp diets 

      C Lim & W Destajo - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A study was conducted to determine the comparative effectiveness of purified, semipurified and crude starch of sago as binders for pelleted shrimp diets. The diet containing semipurified sago starch had the highest water stability (79.1%). The values were nearly the same for the pellets bound with purified and crude sago starch. Reasons for the low binding capacity of purified and crude sago could be that the gel of purified sago is weakened due to purification, and that of the crude sago is due to the spongy material present in the product. Thus, semipurified sago starch is a better source of binder and purified crude sago. From the economic viewpoint, the cost of purified sago is prohibitive for use as binder. Both semipurified and crude sago palm starch are acceptable. Composition of shrimp diets containing various sources of sago palm starch, and binder cost and water stability of shrimp diets containing various sources of sago palm starch tested at 3, 6 and 12 hours, are tabulated.
    • Article

      Effects of exogenous hormone injections on milt consistency in newly caught, wild milkfish 

      JV Juario, GF Quinitio, J Banno & M Natividad - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A study was conducted to determine the effects of single injections of human chorionic gonadotropin (HCG) and Durandron Forte 250 on sperm motility, vitality and density and also on the consistency of milt in newly caught, wild, mature milkfish (Chanos chanos). In contrast to HCG, single injections of Durandron Forte 250 were effective not only in inducing spermiation but also in maintaining newly caught mature males in good running condition for a maximum of 7 days, despite daily handling and collection of approximately 3ml milt.
    • Article

      Effects of furanace on Brachionus 

      MC Baticados, RQ Gacutan & PJ Gutierrez - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Tiger prawn P.monodon) larvae utilize Brachionus a rotifer, as food in the Zoea 3 and mysis stages when they change from an herbivorous to an omnivorous diet. The present work aims to show the effects of furanace on the population growth of Brachionus. Cultures of Brachionus were obtained and fed with Chlorella at a density of 1-2x10 SUP-6 cells/ml. Five liters of the culture water were placed in each of 4 white, circular, 152x304 mm plastic basins. The mean initial densities of the rotifer ranged from 26 . 5 to 38 . 5 individuals/ml. The concentrations of furanace were 0, 1, 2 and 3 mg /l. The cultures were vigorously aerated. Population growth was observed after 3, 6, and 9 hours of exposure. The cultures were thoroughly mixed before samples were taken to ensure an almost equal distribution of the rotifers in the water. To facilitate the counting of the rotifer, one drop of Lugol s solution was added to each sample. This immobilizes the rotifer as well as stops further reproduction. Individuals with only the lorica left or with badly deformed lorica were considered dead. Population counts were done using a Sedgwick-Rafter counting chamber. Among the different durations of exposure, the percentage survival of the populations in the furanace baths were highest after 3 hr. There were slight increases in the control and 2 mg/l and slight decreases in 1 and 3 mg/l. The differences in the mean densities are statistically insignificant at . 01 significance level. After a 6-hr exposure, the control population reached its peak density with a survival of 89%. Populations in furanace baths decreased to 88 . 5% in both 2 and 3 mg /l followed closely by 87% in 1 mg/l. Again, no statistical differences exist among all the levels. The mean percentage survival in 1 and 2 mg/l increased (89% and 91%, respectively) after a 9-hr expsoure, while those in the control and 3 mg/l decreased to 86 . 5% and 88 . 25%, respectively. There were no marked differences in appearance noted among the individuals in furanace baths and those in the control.
    • Article

      Effects of increased stocking density and supplemental feeding on the production of milkfish fingerlings 

      CT Villegas & I Bombeo - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Experiments were conducted to determine the effects of increased stocking density and supplemental feeding on survival and growth of milkfish (Chanos chanos) fry to fingerling stage and also to evaluate the profitability of supplemental feeding in the milkfish fry nursery. Results showed that increased stocking density from 50 to 75 fry/m2 increased net income and is profitable. Survival was further increased through supplemental feeding with rice bran, which is cheap and easily obtainable.
    • Article

      Effects of temperature on behavior, growth, development and survival of young milkfish, Chanos chanos Forsskal 

      AC Villaluz & A Unggui - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The effects of 3 temperature treatments on activity, feeding, growth, development and survival of young milkfish (Chanos chanos) were investigated under laboratory conditions. It is believed that the results may be applied to develop a land-based mass production technology in rearing milkfish fry to fingerlings.