Now showing items 82-101 of 125

    • Article

      Polyculture of milkfish (Chanos chanos) and mud crab (Scylla serrata) at two stocking densities 

      MM Lijauco, OQ Prospero & EM Rodriguez - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Mud crabs (Scylla serrata) were cultured singly and in combination with milkfish (Chanos chanos) to compare growth, survival and production rates. Net production of crab was higher in polyculture than monoculture, but the reverse was observed for milkfish.
    • Article

      Polyculture of milkfish (Chanos chanos) and tiger prawn (Penaeus monodon Fab.) with and without supplemental feeding 

      CT Villegas & DD Baliao - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Twelve 1,000 m2 earthen ponds were used to compare the growth rates, survival and production of milkfish (Chanos chanos) and prawn (Penaeus monodon) in monoculture and polyculture systems in shallow brackishwater ponds and without supplemental feeding. The low production and survival rates obtained were attributed to the lack of natural food; the high salinity during the first month of culture could be one of the causes of the high mortality of prawn observed in both mono and polyculture systems. Although the results of the trial were not ecouraging, it is possible that high yields may be obtained from the combination of the 2 species given enough natural food and favourable water conditions.
    • Article

      Preliminary biological evaluation of some formulated feeds for P. monodon 

      F Pascual & L Bandonil - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Rice bran is widely used by fish farmers as supplementary feed while soybean cake is used both as feed and as fertilizer in fishponds. Both fish meal and shrimp head have been found acceptable as feed ingredients. However, not much is known of the acceptability and efficiency of a mixture of these ingredients as feed for Penaeus monodon larvae. Ninety 127-day old P. monodon were measured for length and weight and were randomly divided into nine aquaria each containing 20 liters of water. These were fed lampirong for two months previous to the study. There were three replications for each treatment. Length, weight, and survival rates were used to compare the efficiency of the diets. Weighed amounts of pellets equivalent to 100% of the body weight were fed during the first three days and reduced to 50% thereafter. A stopwatch was used to determine the length of time that elapsed before the shrimps would approach the pellet. Ten shrimps approximately 4 months in age were placed in 10 liters of water in a 25-liter aquarium. Two grams of each pellet type were placed simultaneously on opposite sides of the aquarium. The time that elapsed from the moment the pellets sunk to the bottom up to the time that any one shrimp approached the pellets was recorded. The group fed the imported pellets gained the most. Those fed FP-2s-77 elongated faster than those fed FP-1s-77. Survival rate of those fed FP-2s-77 was 37% while those fed imported pellets was 73%. Both 1s and 2s pellets disintegrated in water easily but the imported pellets were stable even after six hours in water. The attractability test for the pellets showed that the prawns were more readily attracted to the pellets 1s and 2s than to the imported pellets.
    • Article

      Preliminary chemical and physical evaluation of some formulated feeds for P. monodon 

      J Kalaw, L Bandonil & V Dy - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The culture of Penaeus monodon has explicitly defined the need for diet formulations or supplementary feeds that would promote optimum growth and survival of the animal. A total of 28 feed combinations were developed for P. monodon. Fish meal, shrimp head meal, squid head meal, Ascetes spp. rice bran, and soybean cake were used as primary ingredients in these feeds. The commercial vitamin mix No. 22 was added to the dry ingredients. Gelatinized corn starch and wheat flour were used as binders. The pellets were extruded using a portable kitchen grinder with a diameter of 4 mm. The products were either sun-dried for 8 hours or oven-dried overnight at 50 degree C to stabilize moisture at 8-10%. The pellets were then kept in covered glass bottles and stored in the laboratory at room temperature. The cost of the feeds excluding labour were also computed. The pellets were analyzed for protein, fat, carbohydrate, crude fiber, ash, and moisture contents using standard procedures. They were also analyzed for water stability. To test the stability of pellets in water, 2-g samples were placed in plankton nets (mesh #40) and suspended in water for two, and six hours. The undissolved samples were then vacuum-dried and the moisture determined. Cost of the feeds ranged from P1.10 to P2.60 per kg depending on the feed ingredient. Squid and Ascetes spp. were rather expensive for use as basic ingredients. Proximate analysis of dry weight showed percentage protein content ranged from 20-63 g; fat, 8-20 g; carbohydrate (by difference), 11-36 g; ash, 8-28 g; moisture, 6-11 g; and crude fiber, 5 . 13 g. Stability tests showed that after two hours, 35-88% of solids remained intact and after 6 hours, 20-55% of the pellets remained undissolved. When a pellet disintegrates easily, pollution of the water occurs. Chances for the shrimp to feed on the pellet is minimized when the pellet is unstable. Thus, the search for a more compact feed pellet has to be continued.
    • Article

      Preliminary histological study of the ovarian development of the giant tiger prawn, Penaeus monodon 

      H Motoh - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This study was undertaken to determine structural characteristics within the gonads which might serve as an index to age and longevity and furnish information on the frequency of spawning of an individual.
    • Article

      Preliminary report on the first production of the crab stages of alimasag, Portunus pelagicus (Linnaeus) 

      H Motoh, D de la Peña, M Dimaano & E Tampos - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      An experiment was undertaken studying the early life history of Portunus pelagicus in order to obtain information of relevance to rearing techniques for crabs.
    • Article

      Preliminary studies on growth and survival of Penaeus japonicus postlarvae fed with Tapes and commercial formula feeds 

      CT Villegas - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Growth and survival of P. japonicus postlarvae was studied using Tapes philippinarum and commercial formula feeds. After a 28-day feeding period, the highest survival rate of 100% was obtained in prawns receiving Diet-B, followed by those on Tapes Kyowa Hakko shrimp meal with survival rates of 80 and 76.7%, respectively. The lowest survival rate of 48.3% was obtained among postlarvae fed with squid meal. In this batch cannibalism was observed which resulted in low survival. Growth was highest in the postlarvae fed with Kyowa Hakko and mysid feeds. Diet-B gave a slightly lower weight increase but gave similar gain in length. The composition of the artificial diet, Diet-B, and growth and survival rates are tabulated.
    • Article

      Preliminary studies on predicting the setting season of oysters for the benefit of shellfish farmers 

      AL Young, E Gargantiel & R Traviña - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Preliminary findings from a spatfall forecasting programme initiated in April 1981 at Himamaylan River, Negros Occidental are presented. Two main activities are involved: 1) monitoring of daily counts of oyster larvae in the plankton; and 2) monitoring of actual setting of oysters on standardized collectors put in the vicinity of oyster farm sites. Findings indicate that when the count of mature larvae exceeds 5 per 100 ml sample and persists for at least 3 days, spat may be expected to occur shortly afterwards.
    • Article

      Preliminary studies on the holding of live mussels after harvest 

      WG Yap & CF Orano - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Green mussel (Perna viridis) were harvested to study the applicability of chilling to keep the mussels alive for a longer period of time and to review existing methods of packaging and transport. Data obtained from preliminary studies indicated the effectiveness of keeping mussels alive as long as 4 days with minimal mortality rates.
    • Article

      A preliminary study on the evaluation of casein, shrimp meal, squid meal and spirulina as protein sources for Penaeus monodon (Fabricius) postlarvae 

      C Lim, P Suraniranat & R Platon - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      P. monodon postlarvae were fed with fresh brown mussel (Modiolus metcalfei) meat, and artificial diets containing casein, shrimp (Metapenaeus ensis) meal, squid (Loligo) meal, and Spirulina as protein sources at a rate of 20% of their biomass per day for a period of 10 days. No statistical difference was found among the weight gains of shrimp fed on various experimental diets. However, shrimp fed squid meal diet had highest weight gain followed by shrimp meal, fresh brown mussel meat, casein and Spirulina . Shrimp fed squid meal diet had a significantly better feed conversion and those receiving other experimental diets. Poorest fed conversion was observed in shrimp fed Spirulina. The protein efficiency ratio was statistically highest for the squid meal diet, with the lowest value again for Spirulina diets. Survival rate was significantly highest for shrimp fed the shrimp meal diet. No statistical differences were found among shrimp fed other experimental diets. Appropriate data are tabulated.
    • Article

      Preliminary study on the internal genital organ of the giant tiger prawn, Penaeus monodon 

      H Motoh - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This report gives information on the anatomy of the internal genital organs of male and female Penaeus monodon.
    • Article

      A preliminary study on the protein requirement of Chanos chanos (Forskal) fry in a controlled environment 

      C Lim, S Sukhawongs & F Piedad-Pascual - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Growth rate of fish appeared to be related to the levels of the protein in the diet up to 40%. Fish fed diets containing 50 and 60% grew slower than those fed 40%, and the optimum level appears to be 40% when fed to fry at a rate of 10% of body weight. Best feed conversion of 1.96 was also obtained from the 40% protein diet. Mean survival rates were low in all treatments, but highest for the 40% protein diet. The competition of 5 isocaloric experimental diets containing various levels of protein are tabulated, as are weight gains, diet conversions and survival rates for milkfish fry fed various dietary levels of protein. Growth curves for milkfish fry are shown, and the relationship between weight gains of milkfish fry and the dietary levels of protein are illustrated.
    • Article

      A preliminary study on the use of the local variety of ipil-ipil Leucaena leucocephala as a protein source for prawn feed 

      FP Pascual - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A study was carried out to determine the effect of 10 or 20% leaves or seeds in the diet of Penaeus monodon , and the extent to which local ipil-ipil (Leucaena leucocephala ) could replace head shrimp meal. A brief description is given of the experimental methodology, and details of composition of the diet, proximate chemical composition of the diets, mean weight gain and survival of Penaeus monodon larvae fed shrimp head meal and ipil-ipil as protein sources, are presented. Mean weight gains for all groups were poor and not statistically significant. Survival rates for those fed 10% ipil-ipil were significantly higher than those fed 20% diets. Wherever the survival rate was high, mean weight gain was low and vice versa. The presence of the toxic alkaloids mimosine in ipil-ipil could have caused the low survival rate.
    • Article

      Preliminary trials in Artemia rearing and salt production in earthen salt ponds 

      J Primavera, D Estenor, P Acosta & F Estepa - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The authors report on the production of Artemia obtained on a 0.5 ha pilot project with combined trials in Artemia rearing with solar salt production during the dry seasons and with production of milkfish (Chanos chanos) fingerlings and/or prawn (Penaeid sp.) juveniles during the rainy season in the Philippines.
    • Article

      Preserved algae as food for Penaeus monodon larvae 

      O Millamena & EJ Aujero - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Uni-algal cultures of C. calcitrans, S. costatum, T. chui and Isochrysis sp. obtained from the laboratory were harvested. The harvest, preserved by either freezing or sun-drying, was fed to the larvae of P. monodon . Among the test algal species, Chaetoceros and Tetraselmis were used in larval feeding trials with frozen food while Chaetoceros, Tetraselmis and Isochrysis species were utilized in feeding experiments with sun-dried algae. Their relative effects on larval survival and development were assessed. Results showed that, except the alum-flocculated cells, both frozen Chaetoceros and Tetraselmis can support survival at the zoea stage. Best survival of 68% was atained with dried Chaetoceros followed by Tetraselmis at 44%. Dried Isochrysis did not perform as well, a significantly low survival of only 25% was obtained.
    • Article

      The propagation of the mud crab Scylla serrata (F.) de Haan 

      AFD Laviña & AS Buling - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The mud crab Scylla serrata is an important commercial species found in many brackish areas in the Philippines. During spawning and hatching, the berried females migrate to the sea. Seeds for pond stocking are obtained from the wild. Because of the unpredictability of seed supply, there is a need to propagate the species artificially. Thus, spawning, larval rearing, maturation, and rematuration of the species are being studied. The first attempts at hatching S. serrata were successful with rates varying between 75% and 90%. Two out of three trials on larval rearing yielded a few megalops. The first zoeal stages were fed diatoms, rotifers, Artemia salina, and bread yeast. Overfeeding programs were implemented during the critical premolting periods to prevent weakening of the larvae and lessen cannibalism. Larval weakening during the premolt makes them susceptible to attacks by fungi like Lagenidium and ciliates like Vorticella. S. serrata larvae survived salinity levels as low as 15 ppt until the 14th day of rearing. Other larvae were able to survive in salinities of 30-32 ppt for 8 to 13 days. Zoeal molting was hastened by lowering the salinity to 25-27 ppt. Artificial broodstocking of juveniles and adult crabs has been made possible using a simple refuge system made of three-compartmented hollow blocks. This system has been helpful in minimizing fighting among crabs. Remarkable growth rates have been observed with feeds like mussel meat and trash fish. Average growth increments of 11 mm carapace length and 20 . 35 g body weight have been observed every fortnight. A newly spent spawner could gain additional weight of 22.5 g in only 6 days. Feeding rates of juveniles and adult crabs have been established based on the average body weight from an experiment using mussel meat. Crabs feed more at night. In another experiment, eyestalk ablation was found to be effective in inducing growth and mating. Aside from hastening the molting process, copulation is induced even among the small crabs (average carapace length = 55 mm). Natural mating lasts about 26 hr. A copulation which lasted for seven days with a break in between was observed.
    • Article

      Reduction in Chaetoceros populations by furanace 

      MCL Baticados & RQ Gacutan - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      One of the most promising prophylactic agents being tested to control Penaeus monodon larval diseases is furanace (6-hydroxymethyl-2 2(5-nitro-2-furyl) vinyl pyridine). To evaluate further its suitability as a chemotherapeutic agent, its effects on the population growth of Chaetoceros calcitrans, the diatom used as feed for the zoeal stages, was examined. Chaetoceros populations of uniform density (initial density in all runs: 130-141x10 -3 cells /ml) were placed in nine white, circular (382 sq cm), plastic basins. The physio-chemical characteristics of the culture water were as follows: salinity, 28 . 5-30 . 0 ppt; pH, 8 . 62-8 . 72; temperature, 23-25 . 5 degree C; dissolved oxygen, 7 . 1-9 . 3 ppm; nitrate, 0 . 03-0 . 07 ppm; and ammonia, 0 . 005-0 . 03 ppm. Preweighed furanace granules were dissolved in the culture water, with resulting concentrations of 1 and 2 mg/l (3 replicates each). A set of replicates without furanace served as the control. Population counts of the diatom were taken after 2, 4, 6, 8, and 10 hr exposures. After 4 hr, the population decreased in all three levels. The population in 2 mg/l furanace showed the lowest count and that in control the highest. The population means are not statistically different from one another. The results of the study show that the furanace causes reductions in Chaetoceros population at all durations of exposure.
    • Article

      Relationship between diet composition and growth rate of the zoeal and mysis stages of Penaeus japonicus Bate 

      CT Villegas & A Kanazawa - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Diets containing Chaetoceros gracilis plus Artemia nauplii artificially prepared diet, Diet-B, and two commercial feeds Tapes and mysid meals, were fed to larvae of P. japonicus. Highest survival rate was obtained when larvae were fed with Diet-B. The results show that the early larval stages of P. japonicus can be reared on artificially prepared diets. Since the chemical composition of the diet is known, it can be used as supplemental data for larval feeding development and nutritional requirement studies for the early larval stages of Penaeus japonicus and/or other penaeids. Information is tabulated on feeds and feeding rates used, composition of the artificial diet, fatty acid composition of lipids of the different diets, and of the sterols of the different diets.
    • Article

      Results of drift card experiments and considerations on the movement of milkfish eggs and larvae in the northern Sulu Sea 

      S Kumagai & T Bagarinao - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      For a period of one year beginning December 1977, drift card experiments were conducted off the western and southern coasts of Panay Island to determine the surface currents in the area. Of a total 2,384 drift cards released during the study, 382 (16.02%) were recovered, 92% of them within 30 days following dispatch. The surface currents in the study area are strongly influenced, in direction and speed, by the prevailing monsoon winds. During the NE monsoon period, the surface currents move away from the coast; during the SW monsoon, toward and/or parallel to the coast. Based on the results, the probable movement and transport of milkfish (chanos chanos) eggs and larvae from the spawning ground to the fry collection ground are also discussed.
    • Article

      Salinity preference of the milkfish Chanos chanos Forskal 

      JV Juario & C Dueñas - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Extended abstract only.