Recent Submissions

  • Viability of frozen algae used as food for larval penaeids

    Aujero, Eva; Millamena, Oseni (1979)
    Freezing with added chemicals as flocculants and protectants was assessed as a means of preserving stock cultures of 4 algal species used for larval penaeid food Chaetoceros calcitrans, Skeletonema costatum, Tetraselmis chuii and Isochrysis galbana. The maximum storage effectability of the preservation techniques for each species was also determined.
  • Catch composition of penaeid prawns caught with fish corrals at Batan Bay, Philippines

    Motoh, Hiroshi; Solis, Noel; Caligdong, Edna (1979)
    The study was undertaken to ascertain the commercially important species of penaeid prawns caught in Batan Bay, Philippines and their abundance in fish corrals. A total of 12 species were commercially caught: Penaeus monodon, P. semisulcatus, P. merguiensis, P. indicus, P. latisulcatus, P. japonicus, P. canaliculatus, Metapenaeus ensis, M. endeavouri, M. dalli, M. elegans, and Trachypenaeus fulvus.
  • Survival, maturation, fecundity and hatching rates of unablated and ablated Penaeus indicus H.M. Edwards from brackishwater ponds

    Primavera, Jurgenne H.; Young, Thomas; de los Reyes, Carol (1979)
    Penaeus indicus harvested after three months of rearing in brackishwater ponds and averaging 6.9 g for females and 5.6 g for males were stocked in two 12 cu m flowthrough ferrocement tanks at 240 females and 200 males per tank. The females were ablated on one eyestalk in one tank and remained unablated in the other tank; all males were unablated. Ablated females spawned up to 7 times per female; unablated females spawned up to only 3 times during the two month duration of the experiment. Ablated females produced a total number of 17.5 x 10<sup>6</sup> eggs, 6.6 x 10<sup>6</sup> nauplii, and an average of 23,480 eggs/spawning and 37.8% hatching rate from a total of 757 spawnings. Unablated females produced a total of 2.0 x 10<sup>6</sup> eggs, 1.1 x 10<sup>6</sup> nauplii, and an average of 26.990 eggs/spawning and 53.9% hatching rate from a total of 74 spawnings. Survival of ablated females was 53.5% compared to 69.4% for unablated females; males in both tanks averaged more than 90% survival.
  • Studies on the fungal diseases in crustaceans. I. Lagenidum scyllae sp. nov. isolated from cultivated ova and larvae of the mangrove crab (Scylla serrata)

    Bian, Bo Zhong; Hatai, Kishio; Po, Gilda; Egusa, Syuzo (1979)
    Lagenidium scyllae , a marine mastigomycete from the ova and larvae of the mangrove crab, is described and illustrated as new. The fungus grew at a temperature range of 16-42 C, with an optimum at 22.5-31.8 C. It grew well in peptone-yeast-glucose (PYG) broth containing 2-3% NaCl. In PYG-sea water medium, it grew at a pH range of 5-11.
  • Optomotor reaction of milkfish larvae and juveniles

    Kawamura, Gunzo; Hara, Shiro (1979)
    The development of the optomotor reaction (OMR) in milkfish (Chanos chanos), from the larval, through the metamorphic, to the juvenile stage was observed. The period from the appearance of the pelvic fins until the complete disappearance of the finfold was named &rdquo;metamorphic stage&rdquo;. While the larvae showed strong rheotactic responses, their OMR was somewhat weak. It was clear that the OMR underwent a big change through the metamorphic stage, and became strong and almost perfect in the juveniles.
  • The extraction of mimosine from ipil-ipil (Leucaena leucocephala) by soaking in water

    Pascual, Felicitas; Peñaflorida, Veronica (1979)
    The study aimed to find a cheap and practical method of extracting mimosine from Leucaena leucocephala, otherwise known as ipil-ipil in the Philippines. L. leucocephala leaves are used in cattle, poultry and swine feed and have been tried as a food ingredient in some fish diets. While it contains relatively high amount of protein, its use as feed has been limited because of the presence of toxic substance, mimosine. Findings revealed that soaking the leaves in water was highly efficient for the extraction of mimosine, the longer the duration of soaking the more mimosine was extracted. On the other hand, 87 % of the juveniles Penaeus monodon fed with diets containing L. leucocephala leaves soaked for 24 hours survived, much higher compared to those that were fed with unsoaked leaves for eight weeks.
  • Results of drift card experiments and considerations on the movement of milkfish eggs and larvae in the northern Sulu Sea

    Kumagai, Shigeru; Bagarinao, Teodora (1979)
    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.
  • Occurrence of milkfish, Chanos chanos (Forsskal) eggs around Panay Island, Philippines

    Senta, Tetsushi; Kumagai, Shigeru; Castillo, Nelson (1979)
    The study documents the occurrence of milkfish, Chanos chanos (Forsskal) eggs around Panay Island, Philippines: in Cuyo East Pass, Panay Gulf, Visayan Sea, Sibuyan Sea and Cagayan Islands. Most of the eggs, 545 out of 551, were obtained from Cuyo East Pass compared to Cagayan Islands and Sibuyan Sea while no milkfish egg was recovered from either Panay Gulf or Visayan Sea.
  • Effect of different sex ratios of ablated wild-stock Penaeus monodon Fabricius on maturation, fecundity and hatching rates

    Alava, Rosario; Primavera, Jurgenne H. (1979)
    The study was conducted to determine other sex ratios of ablated wild-stock Penaeus monodon other than the most commonly practiced 1 male: 1 female. Four different sex ratios, 0:1, 1:1, 1:2, and 1:4 male: female were tested in four 4m diameter circular tanks for a period of 55 days. During the first run the 1 male: 2 females ratio gave: (a) the highest percentage of first (42.20%), second (30.00%) and third (33.33%) spawning; and (b) the highest total and average fecundity (3.9 million eggs and 300,692 eggs, respectively). The 1 male: 2 females ratio is recommended on the basis of highest percentage for the first, second and third spawners, total and average fecundity.
  • Acute toxicity of unionized ammonia to milkfish (Chanos chanos Forsskal) fry

    Jumalon, Nepheronia A. (1979)
    The study was conducted to determine the effects of varying concentrations of ammonia to milkfish fry. Two runs of static 96h bioassays were conducted to determine the median lethal concentration (LC 50) of unionized ammonia (NH<sub>3</sub>) to milkfish fry. Test concentrations were based on exploratory 24h and 48h bioassays and were made in three replicates. Reagent grade ammonium chloride (NH<sub>4</sub>Cl) was used to adjust the level of unionized ammonia. The 96h median lethal concentration, determined by the Reed Muench method was calculated at 28.029 ppm NH<sub>3</sub> 29.69 ppm. Even at high concentrations of unionized ammonia, most of the fry mortality occurred after 48 to 96 hours exposure. Severe gill damage occurs only at concentrations above 20 ppm, especially above the LC 50. The high LC 50 value obtain shows that milkfish fry has great tolerance to ammonia, that even fry with severely-damaged gills can still recover days after it is returned to favorable culture condition. The result suggest that observed mortalities of milkfish fry under culture conditions are not due to ammonia toxicity.
  • Transport of sugpo, Penaeus monodon juveniles

    Yap, Wilfredo; Mochizuki, Hideo; Apud, Flor (1979)
    This study was made as an attempt to investigate the optimum packing density and the ice quantity suitable for the transport of Penaeus monodon juveniles. The results revealed that prawns of 40 mg size can be packed to as much as 3,000 per bag. While packing densities above 3,000 per bag containing 8 L seawater and 16 L oxygen can be used only for short transport periods. On the other hand in the ice-quantity experiment, mortality rate was less than 1% in all the bags containing 300 g, 600 g, 900 g and 1200 g of ice. A packing temperature of 20~&rsquo;C must be maintained hence, 50 g of ice per hour should be allowed per box, counting from the moment the box is sealed to the time it is estimated to be opened.
  • Notes on the construction of 12 cu m ferrocement maturation tank for prawn broodstock

    Tolosa, Rodolfo T. (1978)
    The study aimed to develop an economical, rational and easy method of constructing ferrocement tank suitable for P. monodon maturation.
  • Salinity preference of the milkfish Chanos chanos Forskal

    Juario, J.V.; Dueñas, C. (1977)
    Salinity preference of the milkfish fry is described. Milkfish fry which were acclimatized to different salinities have preference for certain salinity which is 32 ppt. Majority of the fry in the control tanks usually prefer to stay either at the bottom or at the uppermost layer; only a few stay at the middle layer. This strongly suggests that milkfish fry that are not caught along the shore by fishermen usually tend to migrate to waters of high salinity. Furthermore, salinity preference of milkfish fry does not change with age.
  • Bioenergetics of the freshwater prosobranch Idiopoma angularis Muller in Laguna de Bay

    Baluyut, Elvira A. (1977)
    This study was made as an attempt to investigate some of the ecological aspects of the freshwater snail Idiopoma angularis Muller in a modern framework of energy flow and mathematical models. It offers the first investigation of respiration (as related to temperature and body size), production (growth), and excretion in the prosobranch I. angularis in Laguna Lake.
  • Effect of temperature on the oxygen consumption of Penaeus monodon postlarvae

    Catedral, F.F.; Sayson, R. (1977)
    The study aimed to determine the oxygen consumption of P. monodon postlarvae at different temperatures. Results suggest dependence of oxygen consumption on both weight of postlarvae and temperature. The relationships appear linear at the temperature range examined. Temperature dependence of oxygen consumption suggests that oxygen requirement (and metabolism) increases with temperature.
  • Bacteria from seawater used in Penaeus monodon larval cultures

    Llobrera, Alcestis T.; Gacutan, R.Q. (1977)
    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 10<sup>2</sup> to 5.1 -10.0 x 10<sup>5</sup> 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.
  • The effect of various protein levels on the growth and survival rates of Penaeus monodon Fabricius

    Khannapa, Auaychai (1977)
    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 significantly different from the 30% protein level. Feed conversion for the 40% protein diet was 2.8.
  • Larval and postlarval development of the window-pane shell, Placuna placenta L. (Bivalvia: Placunidae)

    Young, Adam (1979)
    Stages of development of P. placenta from the straight-hinge veliger to the adult are described. Mature larvae metamorphose at lengths from 220-230 m. Larvae probably attach byssally to the water surface at metamorphosis and remain in the plankton for some time before finally settling on the mud bottom.
  • Preliminary studies on predicting the setting season of oysters for the benefit of shellfish farmers

    Young, A.L.; Gargantiel, E.; Traviña, R. (1981)
    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.
  • Acute toxicity of un-ionized ammonia to milkfish (Chanos chanos) fingerlings

    Cruz, E.R. (1981)
    The acute toxicity of un-ionized ammonia to milkfish (Chanos chanos) fingerlings was determined using a static bioassay system. Median lethal concentrations found show that milkfish fingerlings have a high tolerance to ammonia and it is unlikely that levels as high as those employed for the acute exposure would be found to occur under natural conditions. Although the threat of acute toxicological effects induced by ammonia are remote, such conditions might be encountered in stressed natural environments or in heavily loaded aquaculture systems.

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