Now showing items 1-20 of 186

    • Book

      First annual report of the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC) for the fiscal year ending December 31, 1973 

      Southeast Asian Fisheries Development Center, Aquaculture Department - 1974 - Aquaculture Department, Southeast Asian Fisheries Development Center
      An illustrated account is presented, covering background (establishment of the department), plan of operation (functions; activities), project site development (Leganes Station, Tigbauan Station, construction of buildings, infrastructure development), research (prawn fry stocking, collection of prawn spawners, research staffing, research tie-up with Mindanao State University, Japanese fisheries experts), equipment (preparation of the list of Japanese donated equipment), organization of the department, funding.
    • Book

      Annual report 1974 

      Southeast Asian Fisheries Development Center, Aquaculture Department - 1975 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The 1974 report describes the development of project sites at Tigbauan and Leganes, where new ponds and labs have been established. The facilities of these labs include covered and open ponds, wet and field labs, a food preparation building, as well as dormitories and housing units. A substation is now operating at Nueva Valencia, investigating the life cycle of tiger prawn, Penaeus monodon, and 5 further substations also exist. Organisational aspects are described, covering scientific staff, equipment, funding etc. The Department s activities are described in detail; these are mainly concerned with shellfish culture and the associated problems. Notes are included on the First Aquaculture Research Conference (April 1974)and 7th SEAFDEC Council Meeting (Dec 1974). Finally, the new and continuing research projects to be conducted during 1975 are listed.
    • Book

      Annual report 1975 

      Southeast Asian Fisheries Development Center, Aquaculture Department - 1976 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • 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 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

      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

      Methods of harvesting and preservation of the diatom Chaetoceros calcitrans 

      OM Millamena, EC Jereos & IR Gorriceta - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Diatom culture and larval feeding experiments were conducted to test the viability and acceptability of preserved algal concentrates. C. calcitrans is characterised by the presence of setae which keep them suspended in cultures and make autoflocculation very difficult. Flocculation was induced by the addition of a floc-forming chemical. Using the optimum conditions, it was possible to harvest the algae within 1-h settling time and with about 84% recovery. The viability of frozen Chaetoceros was determined by actual cell reproduction. Preliminary feeding experiments showed that Chaetoceros can be successfully used as a substitute for fresh diatoms as feed for Penaeus monodon larvae. Simple freezing techniques, with or without the use of protectants has been found convenient for preserving algal concentrates in small volumes for both feeding and culture purposes.
    • 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

      A simple method of tagging prawns 

      LM Rodriguez - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The recognition of individual animals is crucial to many aspects of research. Prawns (Penaeus monodon) present unique difficulties in this respect since they molt regularly. Thus, almost all tagging and marking methods developed for prawns so far have proven inadequate. Some tags or marks are lost during molting; others cause injury to the prawns. A new and efficient method has been developed at the Igang Seafarming Station of the Aquaculture Department.

      Rectangular brass tags measuring 5 mm by 20 mm and numbered consecutively are used. The prawn is held gently but firmly at the base of the carapace with the left hand while the right hand slips the brass tag around the stalk of the unablated eye and presses the tag gently. All tagging must be made under water to avoid stress.

      From May 29 to September 7 to a total of 348 unilaterally-ablated adult female prawns were tagged on the unablated eyestalk in 5 batches to enable individual observations on gonadal maturation, molting, and growth. Periodic examinations were made four times a month to coincide with the different phases of the lunar cycle. On each examination, survival and recovery rates were recorded. The data included death due to immediate mortality during ablation and loss to cannibalism for the duration of the experiments.

      In all five tagging experiments, most of the prawns recovered had their tags intact. These included even dead and molting animals.

      The eyestalk tagging method is suitable for prawns because the tags can be attached without causing injury and has no effect on the rate of growth, maturity, molting and behavior of the animal. The tags are identifiable and permanent; they remain attached to the animal even after death.
    • Article

      Survival rates of different postlarval stages of Penaeus monodon Fabricius 

      JH Primavera - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The objective of this study is to determine survival rates of different postlarval stages upon stocking in the Leganes ponds. Twelve 3m x 2m x 2m suspension nets made of nylon cloth (mesh size = 0.1 mm) were set up in a Leganes Station pond (ave. water depth = 1 m) by means of 3-m long poles stacked at distances approximating the area of each net. The net bottom was filled with topsoil at least 15 cm thick to stimulate the pond bottom. At least 60 cm of the upper edge of each net was above the water level to prevent mixing of water inside and outside the net. P. monodon of stages P11, P15, P21 (from the hatchery) and P25 (from the wet lab) were stocked in the nets at 200/sq m or 1,200 fry/net. Due to lack of fry, only one P25 net was stocked. Each net had two large dried miapi branches as shelter from predation and cannibalism for the young sugpo fry. Fresh lablab was fed at the rate of one pail (approximately 5 kg) every four days per net. Harvest data show relatively higher survival rates for P15 and P18 compared to P11 and P25 with no significant difference between these two stages. The results for P25 may not be valid because the stock came from the wet lab in comparison to the other postlarval stages which were reared in the hatchery. Moreover, the P25 stock had no replicates and the net itself (no. 10) was discovered to have many holes. These preliminary results point to P15 as the best stage for harvest from the hatchery in terms of high pond recovery and lesser expense in rearing compared to older postlarvae.
    • Article

      Bacteria from seawater used in Penaeus monodon larval cultures 

      AT Llobrera & RQ Gacutan - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Bacteria in the seawater used in P. monodon hatchery operations were isolated on Bachmann's agar. The total plate counts in 25 isolations ranged from 1.0 - 5.0 x 102 to 5.1 -10.0 x 105 cells per ml. Out of 124 isolates, 98 (79 percent) were Gram-positive and 26 (21 percent) were Gram-negative. Micrococcus and Staphylococcus were dominant in the former group, while Acinetobacter, Moraxella, Flavobacterium and Alcaligenes were most numerous in the latter. Twenty-nine of the Gram-positive isolates closely resembled Peptostreptococcus, Planococcus, and Pediococcus.
    • 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

      The biology and control of Caligus sp., an ectoparasite of the adult milkfish Chanos chanos Forskal 

      EM Laviña - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      One unidentified species of copepod belonging to the genus Caligus of the family Caligidae was found to infest the adult milkfish broodstock. To control the parasites infesting the adult milkfish, tests were made using the chemical (2,2,2-trichloro-1-hydroxyl)-phosphonic acid-dimethylethol (Neguvon) at a concentration of 0.25 ppm. It is noted that a concentration of 0.25 ppm of Neguvon maintained for 12-24 hours in the sabalo-containing tanks in a closed water system but with aeration is effective in controlling the parasites. Fish mortality during the experiment was due to inadequate aeration in the tanks.
    • Article

      Organic pollution in culture water resulting from excess feed and metabolite buildup 

      OM Millamena & RR Platon - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Penaeus monodon postlarvae were subjected to increasing feed concentrations and their growth and survival rates were recorded. Measurements were made of dissolved organic matter, and ammonia and nitrite-nitrogen concentrations. Survival was highest at the lowest feeding level and decreased as feed concentration increased. It is concluded that although organic matter enriches the food supply for P. monodon postlarvae, at higher concentration levels it can pollute the culture water, which in turn leads to mass mortality of the postlarvae. Secondly, the survival rate of P. monodon postlarvae is directly related to dissolved organic matter concentration, oxygen tension, and ammonia-nitrogen concentrations in the culture water. Even at sublethal levels these adverse environmental conditions decrease the survival rate.
    • Book

      Annual report 1976 

      Southeast Asian Fisheries Development Center, Aquaculture Department - 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • 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

      A suctorean parasite of Penaeus monodon larvae 

      RQ Gacutan, AT Llobrera, CB Santiago, PJ Gutierrez & G Lio - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A new disease caused by a suctorean has been observed in tank-spawned and reared P. monodon larvae. Identification of the etiologic agent pointed to Ephelota gemmipara R. Hertwig, a species commonly found to inhabit hydroid colonies.
    • Article

      Identification and culture of common diatoms as possible feed for Penaeus monodon 

      T Pimoljinda - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Diatoms were collected from Buyuan Bay, and from the hatchery tanks at Tigbauan, to determine the commonly occurring species, the feasibility of culturing these species, and the potential of these selected species as food for larval P. monodon. The commonly occurring diatoms were identified as Chaetoceros calcitrans, Navicula grimmei, Nitzchia seriata, Nitzchia closterium and Amphiprora sp. These diatoms were isolated and unialgal cultures prepared. Protein content analysis using the micro-Kjildahl method gave the following result: C. calcitrans, 11 . 78%; Nitzchia seriata, 25%; Nitzchia closterium, 30 . 5%; Navicula grimmei, 9 . 06% and Amphiprora sp. 8 . 96%.

      Feeding experiments were conducted to determine acceptability of the different diatom species and percentage survival of larval stages Z1 - M2. Larvae were placed in 4-l capacity plastic containers with a stocking density of 10/l. The results of several feeding trials using the different mass-produced diatoms are summarized.

      From the data gathered, C. calcitrans appears to be the most promising candidate as feed for zoea and mysis stages of P. monodon. The average percentage survival of C. calcitrans was 63 . 76% for the 3 trials, and as high as 82 . 22% in the third trial. Comparatively high percentage survival of larvae was also recorded when Nitzchia seriata (48 . 17%) and Nitzchia closterium (67 . 6%) were given as feed, while both Amphiprora sp. and Navicula grimmei gave 0% survival. The poor results with Amphiprora sp. and Navicula grimmei may be due to their low protein content (8 . 96% and 9 . 06%, respectively) and the inability of the larvae to ingest them. Navicula and Amphiprora were observed to cling to the appendages of the larvae and to settle down in the medium making them unavailable to the larvae. Low survival was also noted when frozen C. calcitrans was used (14 . 25%). This may be due partly to the effect of the floculating agent (ALSO4.25 g/l) used in concentrating the diatoms.

      When protein contents of C. calcitrans, N. seriata and N. closterium are compared, the 2 Nitzchia species have relatively higher protein contents than C. calcitrans and, therefore, could be the more desirable feed candidates. However, few feeding trials were made using Nitzchia so that additional investigations will have to be done on this aspect.
    • 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

      Notes on the induced maturation and spawning in four-month-old Penaeus monodon Fabricius by eyestalk ablation 

      JH Primavera & E Borlongan - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The ablation technique consisted of making an incision across the eyeball to allow free flow of fluids while holding the prawn under water, squeezing the eyeball contents outwards, and pinching hard the eyestalk tissue. The cut area heals completely in about a week; no application of antibiotics is necessary. Spent spawners were tagged with thin brass rings (Rodriguez, 1976) around the unablated eyestalk for a separate experiment on rematuration. Two spawning yielding approximately 277,000 eggs were obtained three weeks after ablation, followed four days later by two more spawnings with 160,000 eggs; all four spawners weighed more than 100 g. With a hatching rate of 98% and 78% for the first and second batch, respectively, the spawnings produced viable nauplii. Water temperatures as low as 23°C due to a delayed cold spell in March depressed molting; weakened larvae had to be discharged at the mysis stage. Although ovarian development continued, no further spawnings were obtained due mainly to the onset of bacterial and fungal disease. Infection is initiated in injured portions of the exoskeleton, sometimes penetrating right through the muscles to the ovarian tissues. The non-flowthrough conditions and mussel meat feeding led to fouling of the culture water resulting in consecutive mortalities caused by disease. Female P.monodon held in maturation pens were ablated at the age of 15 months (Santiago, et al., 1976); they averaged only 16 g body weight after four months growth in ponds. In another experiment, pond-reared P.monodon females ranging from 50 to 80 g were ablated at approximately seven months (Aquacop, 1977). The present results show a minimum age of four months from postlarve that P.monodon is capable of ovarian development and spawning upon ablation. However, maturation is probably affected by size as well as age - the four-month old females weighed an average of 100 g in contrast to the smaller animals in the earlier experiments.