Now showing items 1-5 of 5

    • 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

      Effects of salinity, aeration and light intensity on oil globule absorption, feeding incidence, growth and survival of early-stage grouper Epinephelus coioides larvae 

      JD Toledo, NB Caberoy, GF Quinitio, CH Choresca & H Nakagawa - Fisheries Science, 2002 - Springer Verlag
      A series of experiments were conducted to examine the effects of salinity, aeration and light intensity on oil globule absorption, feeding incidence, and growth and survival of early-stage Epinephelus coioides larvae. Newly hatched larvae were transferred to 40-L aquaria at a density of 1500 individuals/aquarium. Larvae were exposed to different levels of aeration (0 mL/min per L, 0.62 mL/min per L, 1.25 mL/min per L, 2.50 mL/min per L, or 3.75 mL/min per L); salinity (8 ppt, 16 ppt, 24 ppt, 32 ppt, or 40 ppt); and light intensity (0 lx, 120 lx, 230 lx, 500 lx, or 700 lx) for 4–6 days. Twenty larvae were sampled daily at 11:00 hours to measure for total length (TL), oil globule volume, and feeding incidence. Survival rates were determined by counting the total number of larvae remaining in each aquarium at the end of the experiment. Significantly higher survival rates (P < 0.05) were observed at aeration levels of 0.62 mL/min per L and 1.25 mL/min per L, at salinity levels of 16 ppt and 24 ppt, and at light intensities of 500 lx and 700 lx. The influence of aeration level, salinity and light intensity on oil globule absorption, feeding incidence, and growth and survival of early-stage grouper larvae are discussed.
    • Article

      Occurrence and pathology of an Amyloodinium-like protozoan parasite on gills of grey mullet, Mugil cephalus 

      MCL Baticados & GF Quinitio - Helgolander Meeresuntersuchungen, 1984 - Biologische Anstalt Helgoland
      In cultured grey mullets, Mugil cephalus L., mortalities caused by a dinoflagellate-like parasite were observed under normal rearing conditions. Moribund fish were abnormally swimming near the water surface and exhibited haemorrhagic areas on the head, around the mouth and on the body surfaces. Their gills displayed whitish spots as well as haemorrhagic areas and showed excessive mucus production. Microscopic examination of these whitish spots revealed structures highly resembling the trophonts of Amyloodinium attached to the gill filaments. The most consistent feature of this parasitic infestation was lamellar disintegration or degeneration. Early stages of the infestation showed epithelial lifting and lamellar detachment, eventually leading to the disruption of the lamellae and lamellar tissue degeneration. The parasites were associated with large necrotic areas in the gills and caused degeneration of the gill ray tissues. Hyperplasia of the gill epithelium and lamellar fusion were also observed, with the parasites enclosed by the fused lamellae. These structural alteration may have caused osmoregulatory and respiratory difficulties which ultimately led to the observed mortalities.
    • Conference paper

      Survival of yolk-sac larvae of grouper (Epinephelus suillus) under simulated transport conditions. 

      GF Quinitio, JD Toledo, AT Duller & DM Reyes Jr. - In P Lavens, P Sorgeloos, E Jaspers & F Ollevier (Eds.), Larvi '91. Short Communications and Abstracts of Contributions Presented at the International Symposium on Fish and Crustacean Larviculture, 27-30 August 1991, Gent, Belgium, 1991 - European Aquaculture Society. EAS Special Publication No. 15
      Transport of live fish is a routine activity in aquaculture. Various transport techniques have been reported by Berka. Transport of grouper eggs (Epinephelus suillus) between fisheries stations in Thailand is being conducted. However, no report has been made on transport of yolk-sac larvae of this fish. In the Philippines transport of eggs poses difficulties, particularly for hatcheries which are distant from the broodstock rearing site since spawning occurs between 1600 and 1800 h. Eggs can only be collected the following morning and hatching starts around 1200-1300 h (20 h after fertilization). Thus it seems advisable to transport yolk-sac larvae rather than eggs of grouper under such conditions. This study was conducted to determine the feasibility and optimum loading density of transporting grouper yolk-sac larvae for about 2 h.
    • Article

      The effect of various salinity levels and stocking density manipulation methods on the survival of milkfish fry (Chanos chanos Forsskal) during storage 

      GF Quinitio & JV Juario - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Results of the study indicate that the survival rate and increase in body weight did not differ significantly at different salinity levels or at different stocking density manipulation methods. A significant interaction between salinity and stocking density manipulation could not be demonstrated statistically. There apparently is no need to reduce the salinity of the water used in storing milkfish Chanos chanos fry in order to attain higher survival as commonly believed. Sufficient food and maintenance of good water quality are more important than salinity for higher survival of fry during storage.