Now showing items 1-20 of 25

    • Technical Report

      Artificial fertilization of eggs and early development of the milkfish Chanos chanos (Forskal) 

      H Chaudhuri, JV Juario, JH Primavera, R Mateo, R Samson, ER Cruz, EO Jarabejo & JT Canto Jr. - In Induced spawning, artificial fertilization of eggs and larval rearing of the milkfish Chanos chanos (Forskal) in the Philippines, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Technical report / SEAFDEC Aquaculture Department; 4
      Hydrated eggs obtained from a female milkfish were artificially fertilized with the milt collected from a male injected with acetone-dried pituitaries of salmon. The fertilized eggs (1.1 to 1.25 mm in diameter) developed normally in seawater in basins and Petri dishes at a salinity of 30-34 ppt and successfully hatched in 25 to 28½ hours at a temperature of 26.4-29.9°C. The yolk was completely absorbed in about 2½ days and at this period many postlarvae died. A few larvae were reared up to 5 days but all died within 6 days. Effects of feeding the postlarvae from the third day with freshly hatched trochophore larvae of oysters obtained from eggs artificially fertilized in the laboratory could not be ascertained.
    • Article

      Breeding and larval rearing of the rabbitfish, Siganus guttatus (Bloch) 

      JV Juario, MN Duray, VM Duray, JF Nacario & JME Almendras - Aquaculture, 1985 - Elsevier
      Females of Siganus guttatus reared to sexual maturity in canvas tanks were induced to spawn by using human chorionic gonadotropin (HCG, Ayerst) at 500 IU/fish or about 2 IU/g body weight. The amount of HCG used depended on the initial mean egg diameter; the smaller the diameter, the more HCG was used. Fish with oocytes characterized by germinal vesicle migration (mean egg diameter ≥ 0.47 mm) spawned without HCG injection. Fertilization and hatching rates for both treated and untreated fish were more than 90%. The larvae were reared to metamorphosis using rotifers from day 2–17, rotifers + newly hatched Artemia nauplii from day 18–20 and rotifers + newly hatched Artemia nauplii + artificial feed from day 21–35. In addition, Isochrysis galbana was introduced to the rearing tanks from day 1–10 and Chlorella sp. and/or Tetraselmis sp. from day 1–35. Survival rates of larvae tended to be lower as the broodstock became older.
    • Conference paper

      The commercial production of green grouper fingerlings, Epinephelus suillus, from wild caught fry - an industry experience 

      JV Juario, JR Silapan & LL Silapan Jr. - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Wild-caught fry of the green groupers, Epinephelus malabaricus and E. suillus ranging in standard lengths (SL) from 1.5 to 3.0 cm were bought from different fry dealers all over the Philippines. These were reared from 1.0 to 2.5 months in 10 to 40 m3 (small) concrete tanks, in 240 m3 (large) concrete nursery tanks with sandy bottom, in 10 m3 hapa nets installed either in large nursery concrete tanks with sandy bottom or in 0.8 to 1.0 ha earthen ponds. The initial stocking density was 33-150/m3. When the fingerlings reached 5 to 7 cm SL, these were harvested and stocked in cages. The wild fry were fed adult brine shrimps for the first few days and later, trash fish. Rearing water in small concrete tanks was changed daily while that in large nursery tanks and hapas was changed only when dissolved oxygen level was about 4 ppt or lower. Survival rates ranged from 3% to 64%. Although survival rates varied, rearing grouper fry in hapa nets installed in earthen ponds were found to be the most suitable for the commercial production of grouper fingerlings to a size suitable for stocking in cages. The large variation in survival rates is attributed mainly to the quality of wild fry bought from different fry dealers all over the country and the occurrence of diseases during the culture period. The problems encountered in the commercial production of fingerlings are discussed.
    • Article

      Early effects of nutritional stress on the liver of milkfish, Chanos chanos (Forsskal), and on the hepatopancreas of the tiger prawn, Penaeus monodon (Fabricius) 

      V Storch, JV Juario & FP Pascual - Aquaculture, 1984 - Elsevier
      After periods of food deprivation and subsequent feeding, hepatocytes of Chanos chanos fry and R-cells of Penaeus monodon juveniles were investigated by means of transmission electron microscope. They clearly reflect the quality of different diets and thus can be used as monitor cells. For purposes of comparison, the same diets were offered to land-dwelling isopods which are known to accept a variety of different diets. Thus, this technique could also be used as a method of determining the effectiveness of binders in artificial diets.
    • Article

      Effect of different diets on the ultrastructure of hepatocytes of Chanos chanos fry (Chanidae: Teleostei): An electron microscopic and morphometric analysis 

      V Storch, W Stählin & JV Juario - Marine Biology, 1983 - Springer-Verlag
      The hepatocytes of milkfish fry offered different artificial diets (carbohydrate-, lipid-, protein-oriented) and live food (Artemia spp., Brachionus plicatilis) differ considerably both qualitatively and quantitatively as was shown by means of transmission electron microscopy and planimeter. Food deprivation, too, resulted in ultrastructural alterations of milkfish fry hepatocytes. Thus, this cell type might be used as an indicator of quality and quantity of food in teleosts.
    • Article

      The effect of starvation and subsequent feeding on the hepatocytes of Chanos chanos (Forsskal) fingerlings and fry 

      V Storch & JV Juario - Journal of Fish Biology, 1983 - Academic Press
      Excised liver sections of the milkfish, Chanos chanos, fry and fingerlings were studied by transmission electron microscopy. The hepatocytes underwent marked ultrastructural alterations in response to food deprivation of 10-day starvation for fry and 2 months for the fingerlings. The prominent features characterizing the hepatocytes of starved fish were: a reduction of cell and nucleus size; apparent loss of nucleoli; condensation of chromatin material in fry; loss of stored glycogen; reduction of ER profiles; increase in the number of electron-dense bodies containing large amounts of iron in fingerlings; and an increase in mitochondrial size. These changes were reversible following short periods of re-feeding, i.e. 2 days for fry and 4 days for fingerlings, using natural food for the fry and formulated diet for the fingerlings.
    • Article

      Effect of thyroxine on growth and development in post-yolk-sac larvae of milkfish, Chanos chanos 

      TJ Lam, JV Juario & JE Banno - Aquaculture, 1985 - Elsevier
      Post-yolk-sac larvae of milkfish, Chanos chanos (commonly referred to as “fry”) were collected along the shore in the Philippines. Treatment of these long, slender and transparent larvae with L-thyroxine-sodium (Eltroxin, Glaxo) by immersion in 0.5 ppm solution (changed daily) markedly accelerated their growth and development. By day 15 of the treatment, the treated larvae had become silvery, opaque and adult-like in form, whereas the control larvae were still slender and transparent (or at best translucent) with incomplete silvering of the body. 0.1 ppm thyroxine was less effective. Discontinuation of the treatment after 8 days was also less effective as judged by the appearance and weight of the larvae on day 15.
    • Article

      Effects of Chlorella-feeding on larval milkfish, Chanos chanos, as evidenced by histological monitoring 

      H Segner, P Burkhardt, EM Avila, V Storch & JV Juario - Aquaculture, 1987 - Elsevier
      Milkfish, Chanos chanos, larvae were found to suffer 100% mortality within 6 days of feeding when reared on Chlorella sp. According to the liver ultrastructure, Chlorella-fed fish underwent starvation. Likewise, no signs of lipid absorption were observed in the intestine of Chlorella-fed larvae. On the other hand, Chlorella-related histological alterations of the enterocytes in the anterior part of the intestine were different from starvation-related alterations. It is concluded that Chlorella-feeding creates a starvation situation for larval milkfish, but the early losses with this diet are due to an additional stress specifically introduced by Chlorella-feeding.
    • Article

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

      JV Juario, GF Quinitio, JE Banno & MR Natividad - Kalikasan, The Philippine Journal of Biology, 1980 - University of the Philippines at Los Baños
      The study was conducted to study the effects of single injections of Human Chorionic Gonadotropin (HCG) (Ayerst Laboratories, Inc) and Durandron Forte 250, a long-acting androgen preparation (N.V. Organon Oss, Holland), on sperm motility, vitality and density and on the consistency of milt in newly caught, wild, mature milkfish (Chanos chanos). There is an advantage in using Durandron Forte 250 in inducing thinning of milt in mature milkfish during the natural breeding season to facilitate fertilization of eggs. Aside from its long-lasting effect which minimizes handling of fish, it is much cheaper than HCG.
    • Article

      Experiments on the induced breeding of milkfish, Chanos chanos (Forsskal) in 1978 

      JV Juario, M Natividad, J Almendras, J Nacario & J Canto Jr. - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Results indicated that a female having eggs with an average diameter of < 0.7 mm did not respond well to the hormone injections.
    • Technical Report

      A guide to induced spawning and larval rearing of milkfish Chanos chanos (Forsskal) 

      JV Juario & MN Duray - 1982 - Aquaculture Department, Southeast Asian Fisheries Development Center; International Development Research Centre
      Series: Technical report / SEAFDEC Aquaculture Department; No. 10
      The techniques for the artificial propagation of milkfish (Chanos chanos ) developed at SEAFDEC are presented. These include: 1) capture and transport of spawners; 2) determination of sex and weight and maturity of fish; 3) induced spawning (preparation of injection, males, females); 4) fertilization and incubation; 5) larval rearing; and 6) mass production of larval food.
    • Technical Report

      A guide to induced spawning and larval rearing of milkfish Chanos chanos (Forsskal) 

      JV Juario & MN Duray - 1983 - Aquaculture Department, Southeast Asian Fisheries Development Center; International Development Research Centre
      Series: Technical report / SEAFDEC Aquaculture Department; No. 10
      The techniques for the artificial propagation of milkfish (Chanos chanos ) developed at SEAFDEC are presented. These include: 1) capture and transport of spawners; 2) determination of sex and weight and maturity of fish; 3) induced spawning (preparation of injection, males, females); 4) fertilization and incubation; 5) larval rearing; and 6) mass production of larval food.
    • Article

      Histological observations on the rearing of milkfish, Chanos chanos, fry using different diets 

      H Segner & JV Juario - Journal of Applied Ichthyology, 1986 - Blackwell Publishing
      Six different diets, commonly used in the Philippines for rearing milkfish, Chanos chanos, try, were tested by means of growth, survival and histology. These diets included:

      a) live food (Artemia nauplii); b) two different dry feeds; c) natural feed supplements (rice bran, egg yolk); d) a mixture of live and dry feeds. The mixed diet was found to give the best results, closely followed by live food. The dietary value of one of both artificial feeds improved with increasing age of the fish, whereas the other was clearly inadequate. The same was true for the natural compounds. Results obtained from statistical and histological analyses were congruent; the latter provided additional insights not obtained with statistic data alone.
    • Conference paper

      Histopathology of chlorella-feeding in larval milkfish, Chanos chanos 

      Unicellular algae, particularly Chlorella, are widely used as starter feeds for marine finfish larvae. However, milk fish larvae when reared on Chlorella sp., suffered morality up to 100% within the first days of feeding (Fig. 1). Morality induced by Chlorella occurred earlier than that induced by starvation. The present Communication describes histopathological changes in liver and intestines of mlikfish larvae fed with Chlorella sp., copared with starvedor Artemia-fed fish. Feeding the larvea with Artemia for 7 days evofed (Ø 12-16 micro m) hepatocytes, with a well-developed and orderly arranged rough endoplasmic reticulum (rER). Greater amounts of glycogen were deposited. Whereas those fed with Chlorella (Fig. 2) resulted in cellular shrinkage (Ø 5-7micro m), complete absence of stored products, degeneration of rER. swelling of mitochondria and augmentation of lysosome-like structures (compare also Juario & Storch 1984). Starvation-related alterations of hepatocyte ultrastructure were essentially similar.

      The intestinal tract of milkfish larvae is subdivided into pharynx, esophagus, stomach, intestines I(making up to 70% of gut length), II(up to 20%), and III (up to 10%). Nutritional related changes were only observed in intestines I and II. In Artemia-fed specimens there was intensive lipid absorption in I (Fig. 3) and well-developed supranuclear vacuoles in II (Fig. 4). Under starvation, The first part of the intestine was characterized by partial cellular hydrops, autolyic vacuoles (Fig. 5) and a dissolution of basal labyrinth. The supranuclear vacuoles of II were reduced to smaller, electron dense inclusions (Fig. 6). Chlorells appeared partially digested in the gut. It evoked pathological intrcellular vacuolation of the epithelial cells and bizarre forms of the nuclei in I (Fig. 7). In II, changes were similar to starved larvae (fig. 8).

      The present report is another example of high moralities occurring among fish larvae reared on live feeds (compare Eckmann 1985).
    • Article

      Induced breeding and larval rearing experiments with milkfish Chanos chanos (Forskal) in the Philippines 

      JV Juario, MN Duray, VM Duray, JF Nacario & JME Almendras - Aquaculture, 1984 - Elsevier
      Salmon pituitary homogenate was used alone or in combination with human chorionic gonadotropin, to induce spawing in captive and wild adult milkfish at ambient temperature (26–30°C) and salinity of 34%.. Healthy or slightly injured females having oocytes with a minimum mean diameter of 0.66 mm could be induced to spawn in captivity using a total dose of 20 mg SPH/kg + 3000 IU HCG/kg given in two injections. Badly injured females did not respond readily to the hormone and required more than two injections to induce ovulation.

      Milkfish larvae were reared successfully to metamorphosis using only Chlorella-fed rotifers during the first 10 days. Survival rates were greatly improved when, aside from Chlorella and Chlorella-fed rotifers, Isochrysis galbana and Tetraselmis chuii were added to the rearing tanks.
    • Induced spawning and larval rearing of milkfish 

      JV Juario - In Technical Consultation on Available Aquaculture Technology in the Philippines, February 8-11, 1979, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Induced spawning of sea bass, Lates calcarifer, and rabbitfish, Siganus guttatus, after implantation of pelleted LHRH analogue 

      B Harvey, JF Nacario, LW Crim, JV Juario & CL Marte - Aquaculture, 1985 - Elsevier
      Captive Lates calcarifer broodstock at Tigbauan, Iloilo (Philippines) were implanted with cholesterol-based pellets of the LHRH analogue D-Trp6-desGly10-LHRH ethylamide or D-hArg(Et2)6, Pro9-NHet-LHRH at doses between 9.0 and 23.5 μg/kg body weight. In May, one of ten LHRH-treated females released partially hydrated ova into the tank 4 days after implantation. In July, at least one (and probably four) of five LHRH-treated females spawned in the tank 2 days after implantation; 2.6 million hatchlings were collected. In August, both LHRH-treated females spawned in the tank 2 days after implantation; 978 000 hatchlings were collected. None of the sham-operated control fish spawned in any of the experiments.

      Captive Siganus guttatus broodstock implanted with silastic-based pellets of the LHRH analogue D-Nal (2)6LHRH spawned 1–2 days earlier than sham-operated controls.
    • Article

      Influence of nutrition on the hepatocytes of Chanos chanos (Chanidae: Teleostei) 

      V Storch, H Segner, JV Juario & MN Duray - Zoologischer Anzeiger, 1984 - Elsevier
      The hepatocytes of milkfish (C. chanos) fry and fingerlings offered a variety of diets differ considerably as was shown by means of transmission electron microscopy. For fry it was shown that a 7 day starvation period results in a heavily altered hepatocyte ultrastructure but that even in this stadium fast regeneration was possible. Chlorella turned out to be the worst diet, among the artificial diets, the trout diet provoked the best regeneration. In fingerlings a prolonged starvation period was necessary to affect hepatocytes. In some cases considerable indications of liver cell degeneration were found after feeding certain diets for 2-3 months. Even dried lumut and lab-lab did not create optimal hepatocyte ultrastructure. Feeding with cod liver oil did not result in deposition of lipid droplets in the hepatocytes of fingerlings, what is in contrast to milkfish fry hepatocytes.
    • Book

      Milkfish culture in brackishwater ponds 

      MM Lijauco, JV Juario, DD Baliao, E Grino & GF Quinitio - 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 4
      The manual is intended as a guide for operation in milkfish farming. It is presented under the following major sections: 1) Handling of fry - counting, storage and transport; 2) Pond layout and construction - selection of farm site, layout, construction, plan and specification; 3) Pond operation, culture and management - nursery pond management and rearing pond operation; 4) Harvest and post-harvest - harvest, post harvest, and processing; and 5) Economics and costing - cost of construction, cost of operation, and production/yield.
    • Conference paper

      Milkfish culture in the Philippines 

      JV Juario - In H Tanaka, KR Uwate, JV Juario, CS Lee & R Foscarini (Eds.), Proceedings of the Regional Workshop on Milkfish Culture Development in the South Pacific, Tarawa, Kiribati, 21–25 November 1988, 1990 - South Pacific Aquaculture Development Project, Food and Agriculture Organization of the United Nations
      In the Philippines, the level of intensity of Chanos chanos culture is categorized into traditional and extensive management. Pond types for different culture systems, stocking practices, acclimation practices, water management, growout culture and harvesting are discussed. Fish pen culture and management are also briefly considered.