Now showing items 1-18 of 18

    • Article

      A comparison between the catching efficiency of two milkfish fry collecting gears and their respective modifications 

      GF Quinitio & G Kawamura - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - SEAFDEC Aquaculture Department
      An experiment was conducted along the shore of Culasi, Antique in Panay to compare the milkfry (Chanos chanos) catching efficiency of the ordinary fry seine against its innovation and the ordinary sweeper against its 2 modifications. Results show that it is possible to replace the wings of the presently used sweeper and the ends of the fry seine with a coarse-meshed netting. This improvement decreases the water resistance of the gears and thus enables fry gatherers to use larger ones thereby giving more catch.
    • Book chapter

      Amino and fatty acid profiles of wild-sourced grouper (Epinephelus coioides) broodstock and larvae 

      VR Alava, FMP Priolo, JD Toledo, JC Rodriguez Jr., GF Quinitio, AC Sa-an, MR de la Peña & RD Caturao - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      This study was undertaken to provide information on the levels of amino acids in the muscle, liver and gonad of wild-sourced broodstock and larvae, as well as in neurula eggs and day 35 larvae from a hatchery. The fatty acid composition of grouper broodstock tissues was also determined. Samples were analysed for crude protein, amino acids, total lipids and fatty acid contents. Muscle contained higher levels of crude protein and amino acids than the ovary and liver. At the early maturing stage, the grouper ovarian protein was 73.3% and lipid was 19.3%, indicating the high dietary requirements of these nutrients for ovarian development. The crude protein and amino acid contents in wild-sourced larvae were higher than that in eggs and larvae from the hatchery.
    • Book chapter

      Changes in the gastrointestinal tract and associated organs during early development of the grouper (Epinephelus coioides) 

      GF Quinitio, AC Sa-an, JD Toledo & JD Tan-Fermin - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      The histomorphological changes in the gastrointestinal tract of Epinephelus coioides and associated organs during its early development were studied. Larvae of E. coioides were reared in 5-tonne tanks using the semi-intensive culture system. Larval samples were collected at days 0, 2, 4, 6, 8, 10, 12, 14, 16, 20, 25, 30, 35, 40, 45 and 60. The total length (TL) of about 10-20 larvae per sampling was measured. At least 3 samples were examined from each stage for longitudinal sections using light microscopy. The digestive tract of day 0 larvae was a straight, undifferentiated tube composed of simple cuboidal cells. At day 2, cellular differentiation was observed in the pharynx, oesophagus, primordial stomach and intestine. The primordial stomach broadened into a voluminous pouch at day 10. The gastric gland was observed in the stomach from day 20. Day 35 seemed to be the proper time to feed larvae with minced fish when using the semi-intensive rearing system. Insignificant histomorphological changes in the metamorphosing grouper larvae were observed from days 40-60.
    • Article

      Comparative study on the embryonic development of three mud crabs Scylla spp. 

      MCD Ates, GF Quinitio, ET Quinitio & RC Sanares - Aquaculture Research, 2012 - Blackwell Publishing
      Morphological changes in the embryos, egg size and development, incubation period and morphological structures of newly hatched zoea of three mud crab Scylla species were determined. The three species exhibited similar embryonic development composed of 10 stages. The mean egg diameter of Scylla serrata was significantly larger (P<0.05) at the prehatch stage. The mean egg diameters of Scylla tranquebarica and Scylla olivacea were similar (P>0.05). The incubation period was the longest in S. serrata and the shortest in S. olivacea. There was a positive relationship between egg size and larval size, as S. serrata exhibited the largest egg size and first zoea. However, no correlation was detected between egg size at prehatch and lengths of the morphological structures of the newly hatched zoea. The three species exhibited similar lengths of cephalic structures, but S. olivacea had significantly shorter (P<0.05) abdominal structures. The duration of spawning from ablation was the shortest in S. tranquebarica and the longest in S. olivacea. The study is relevant to aquaculture and fisheries management of Scylla species.
    • Article

      A comparison of the annual changes in testicular activity and serum androgen levels between the early and delayed maturing groups of male Cottus hangiongensis 

      GF Quinitio, A Goto & H Takahashi - Environmental Biology of Fishes, 1992 - Springer Verlag
      Annual changes in testicular activity and concentration of two serum androgens were monitored in two groups of the river-sculpin Cottus hangiongensis collected from the upper and lower reaches of a river at southern Hokkaido, Japan. One of them (early maturing group) underwent testicular maturation with aberrant spermatids and spermatid masses produced during the reproductive cycle. Moreover, regular seasonal changes in serum testosterone and 11-ketotestosterone concentrations were observed. On the other hand, in the other group (delayed maturing group), although body size of the fish was large enough to undergo reproduction, annual changes in gonadosomatic index and testicular activity did not vary much. During the months of active testicular development in the early maturing group, spermatogenesis was observed to begin in some regions of the testes of delayed maturing fish, but always resulted in the formation of aberrant spermatids and spermatid masses. Moreover, concentration of serum androgens did not significantly vary throughout the year. Results suggest that low androgen production is a proximal factor for delayed sexual maturity in the delayed maturing group, and that the occurrence of aberrant spermatids and spermatid masses during spermatogenesis is not linked to the delayed maturity.
    • Conference paper

      Egg quality of grouper Epinephelus coioides fed different fatty acid sources 

      GF Quinitio, RM Coloso, NB Caberoy, JD Toledo & DM Reyes Jr. - In D MacKinlay & M Eldridge (Eds.), The Fish Egg: Its Biology and Culture Symposium Proceedings. International Congress on the Biology of Fishes, 14-18 July 1996, San Francisco State University, 1996 - American Fisheries Society, Physiology Section
      Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enriched fish by catch (TFC), and commercial HUFA A-enriched fish by catch (TFS) was monitored. Monthly egg production, spawning frequency, fertilization rate, egg viability, and hatching rates of the control were significantly higher compared to TFS Egg production. Spawning frequency and hatching rate of TC and TFS were not significantly different. Results suggest that varying the species of fish by catch could provide the requirements of E. Coioides broodstock so as to provide quality eggs.
    • Book chapter

      Environmental factors affecting embryonic development, hatching and survival of early stage larvae of the grouper (Epinephelus coioides) 

      JD Toledo, NB Caberoy & GF Quinitio - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      These series of experiments were conducted to determine the effects of density (200, 400, 800 and 1600 eggs/litre), salinity (8, 16, 24, 32 and 40 ppt), aeration (0, 0.62, 1.25, 2.50 and 3.75 ml/min/litre) and light intensity (0, 120, 230, 500 and 700 lx) on the survival of fertilized eggs and early stage larvae of Epinephelus coioides. Under statice incubation conditions, the highest egg viability, hatching rate and percentage of normal larvae were obtained at a stocking density of 400 eggs/litre with moderate aeration (100 ml/min) and salinity of 32-42 ppt. Gentle aeration at 0.62 to 1.25 ml/min/litre, rearing water of 16 to 24 ppt and a light intensity of 500 to 700 lx maximized the survival of early stage E. coioides larvae in the hatchery.
    • Technical Report

      A guide to the establishment and maintenance of milkfish broodstock 

      CL Marte, GF Quinitio, LMB Garcia & FJ Lacanilao - 1984 - Aquaculture Department, Southeast Asian Fisheries Development
      Series: Technical report / SEAFDEC Aquaculture Department ; no. 11
      The manual describes methods used at the SEAFDEC Aquaculture Department in order to establish milkfish broodstock. It is presented under the following major section headings: Establishing broodstock farms; Farms for rearing bangus juveniles; Maturation cages for rearing broodstock to maturity; Gathering data; Spawning and egg collection; and Larval rearing.
    • Article

      Induction of sex change in female Epinephelus coioides by social control. 

      GF Quinitio, NB Caberoy & DM Reyes Jr. - The Israeli Journal of Aquaculture-Bamidgeh, 1997 - Society of Israeli Aquaculture and Marine Biotechnology
      Mature female groupers (Epinephelus coioides) of different sizes were stocked in three floating net cages (2 fishes each) and in tanks (2-4 fishes) to induce sex change in the bigger female grouper after isolation from the original group. All the bigger fish (initial body weight 5.0-6.1 kg) in the floating net cages changed into males by the end of the experiment, while the smaller ones (initial body weight 4.5-5.2 kg) remained female. The fastest sex change was in cage 1 where the bigger fish had atretic oocytes one month after stocking and was milting after four months. In the other cages, milt production in the bigger fish was observed 6-10 months after stocking. In the tank-reared groupers, the biggest fish (initial body weight 6.4 kg) in the tank with four fishes was found to be milting about two months after stocking while the smaller fishes (initial body weight 3.4-4.0 kg) were still females. The fishes started to spawn two months later. In another tank that was stocked with two females, no sex change was observed in the bigger fish even 16 months after stocking. These results indicate that female groupers can be sexually changed into male by social control at the shortest period of four months in floating net cages and two months in tanks. However, there may be cases wherein sex change will not occur.
    • Book chapter

      Lipid nutrition studies on grouper (Epinephelus coioides) larvae 

      VR Alava, FMP Priolo, JD Toledo, JC Rodriguez Jr., GF Quinitio, AC Sa-an, MR de la Peña & RD Caturao - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      The main objectives of this project were to study the lipid chain transfer from the egg stage through hatching and the patterns of lipid conservation or loss during starvation and feeding of larvae in order to elucidate the lipid metabolism of grouper (Phase 1); to determine the fatty acid composition of highly unsaturated fatty acid (HUFA) boosters and enriched live food organisms to enable the possibility of choosing food organisms that provide various dietary levels and ratios of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA, Phase 2); and to determine the effect of Brachionus and Artemia, containing different levels and ratios of DHA:EPA:ARA, on the growth and survival of grouper larvae (Phase 3). Total lipids (TL) of samples were extracted and separated into neutral (NL) and polar lipids (PL). The samples collected in Phase 1 were floating neurula eggs, newly hatched (NHL) and unfed 4-day larvae; larvae fed with live food organisms for 25 and 35 days or starved for 3 days; and wild-sourced larvae starved for a week. In Phase 2, the samples collected were phytoplanktons, Brachionus cultured in phytoplankton for 4 days, Diaphanosoma celebensis and Pseudodiaptomus annandalei. In phase 3, larvae were fed Brachionus until day 14 and at day 25 with Artemia. E. coioides eggs contained high DHA, EPA and ARA, demonstrating their importance in larval development. Larvae primarily spent NL as energy, whereas PL was generally conserved. Wild grouper larvae had higher levels of PL than NL, whereas hatchery-sourced eggs and larvae contained higher levels of NL than PL. Based on the lipid content of wild larvae, high phospholipid diets were essential for larvae survival and normal development. A variety of products were effective in enriching the HUFA content (particularly ratios of DHA, EPA and ARA) of live food organisms. HUFA-enriched live food organisms enhanced the growth, survival and pigmentation in grouper larvae.
    • Book chapter

      Localisation of enzymes in the digestive system during early development of the grouper (Epinephelus coioides) 

      GF Quinitio, AC Sa-an, JD Toledo & JD Tan-Fermin - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      This study was undertaken to investigate the occurrence of some digestive enzymes in the gastrointestinal tract during early development in the grouper. This work was conducted to provide information on formulating an appropriate feeding scheme and an artificial diet for the early development of the grouper, Epinephelus coioides. Larvae of E. coioides were reared in 5 tonne rectangular concrete tanks. The digestive enzymes localized were acid phosphatase (ACP), alkaline phosphatase (ALP), nonspecific esterase (NSE), aminopeptidase (AMP), trypsin (TRP), maltase (MAL) and lipase (LIP). Weak enzyme activity occurred during the yolk sac stage. High AMP activity started at day 14 prior to Artemia feeding at day 16. Fluctuations in TRP activity might be related to stomach formation. Occurrence of MAL during early development demonstrated a capacity to digest carbohydrates. An increase in LIP activity coincided with the occurrence of gastric glands. Insignificant changes in digestive enzymes were observed in the metamorphosing grouper larvae from day 40 to 60.
    • Conference paper

      Mariculture techniques for Epinephelus sp. in the Philippines 

      GF Quinitio & JD Toledo - In RD Guerrero III & MP Garcia Jr. (Eds.), Advances in Finfish and Shellfish Mariculture: Proceedings of the First Philippine-French Technical Workshop on Advances in Finfish and Shellfish Mariculture, October 24-26, 1990, Los Baños, Laguna, Philippines, 1991 - Philippine Council for Aquatic and Marine Research and Development; French Embassy in the Philippines
      This paper reviews the status of different techniques that are presently practiced for Ephinephelus sp. culture in the Philippines. Constraints and problems encountered as well as possible solutions are also discussed.
    • 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

      Occurrence of aberrant spermatids in the freshwater sculpin, Cottus nozawae Snyder 

      GF Quinitio & H Takashi - In LM Chou, AD Munro, TJ Lam, TW Chen, LKK Cheong, JK Ding, HW Khoo, VPE Phang, KF Shim & CH Tan (Eds.), The Third Asian Fisheries Forum. Proceedings of the Third Asian Fisheries Forum, 26-30 October 1992, Singapore, 1994 - Asian Fisheries Society
      Light and electron microscopic investigation were conducted on the spermatogenic cell in the testis of the freshwater sculpin, Cottus nozawae. Light microscopic examination showed that two types of spermatids, normal and aberrant, qxisted in the seminal lobule during the regular testicular activity. Both spermaids were mononucleate but the aberrant spermatids ha mor basophilic nucleus than the normal. Aberrant spermatids enlarged and were than released into lumen of the seminal lobules. Ultrastucturally, highly electron-bense granules occurred in the nuclear chromatin of aberrant spermatids. These increased in size becoming the core of chromatin globules which then filled the enlargeed nucleus. The aberrant spermatids when released into the lobule lumen underwent further degeneration.
    • Article

      Possible application of mibolerone for induced sex inversion of grouper Epinephelus coioides 

      GF Quinitio, JD Tan-Fermin & A Nagai - Fisheries Science, 2001 - Japanese Society of Fisheries Science
      Thirty immature juvenile grouper Epinephelus coioides (19-168 g bodyweight, BW) were randomly stocked in four units 6 t tanks to determine if mibolerone can be used to induce sex inversion in groupers. After acclimatization and weaning to artificial feed, the feed given daily (4% BW/day) was supplemented with 0, 50, 100, and 200 μg mibolerone/kg feed for about 18 weeks. Thereafter, the hormone treatment was withdrawn and the experiment was terminated at Week 24. Ten fish were killed for gonad histology at stocking to serve as an initial control while about three to five fish were killed every 8 weeks. In general, ovaries of initial controls showed the presence of moderate stromal cells and gonia and few primary oocytes. At Weeks 8 and 16, ovaries of the control fish (0 μg/kg) were similar to that of the initial control except that primary oocytes increased at Week 24. Gonads of fish fed diets containing 100 and 200 μg/kg had none to moderate spermatocytes and few spermatids at Week 8 and 16, although spermatozoa were not observed, indicating that the fish were undergoing spermatogenesis. Spermatogenesis at 50 μg/kg was not as advanced since only few spermatocytes occurred at Weeks 8 followed by moderate gonia and no spermatocytes and spermatids at Week 16. However, the presence of few primary oocytes was observed when mibolerone was withdrawn suggesting that sex-inversed fish reverted back to a female condition. These results show that sex inversion in juvenile grouper can be induced by oral administration of mibolerone and may have possible application on mature females to produce functional males.
    • Article

      Sensitivity of grouper Epinephelus coioides eggs to handling stress at different stages of embryonic development 

      NB Caberoy & GF Quinitio - The Israeli Journal of Aquaculture-Bamidgeh, 1998 - Society of Israeli Aquaculture and Marine Biotechnology
      The sensitivity of grouper Epinephelus coioides eggs to handling stress at different stages of embryonic development was investigated. Naturally-spawned grouper eggs in floating net cages were collected and handled at the early cleavage, blastula, gastrula, neurula, and eyed stages. Egg viability, hatching rate and percentage of normal larvae were significantly higher (p<0.05) in eggs collected and stocked at the eyed stage than in all other stages. An increasing sensitivity to handling stress was observed in eggs from early cleavage to gastrula, as manifested by the decreasing percentage of viable eggs, hatched, and normal larvae. Sensitivity to handling stress decreased when development reached the neurula and eyed stages. Hatched larvae from eggs handled during the blastula and gastrula stages had high mortalities during the first 3-24 hours after stocking. The results of this study show that grouper E. coioides eggs are most sensitive to handling stress during the early cleavage to gastrula phases. The results imply that harvesting or collection of grouper eggs is best done after neurulation, when the embryo has already formed optic vesicles (eyed stage), to increase egg viability and the hatching rate. It will also minimize mortalities and the occurence of abnormal larvae.
    • Article

      An ultrastructural study on the occurrence of aberrant spermatids in the testis of the river sculpin, Cottus hangiongensis 

      GF Quinitio & H Takahashi - Japanese Journal of Ichthyology, 1992 - The Ichthyological Society of Japan
      The process of spermatogenesis and spermiogenesis in the river sculpin,Cottus hangiongensis, was observed ultrastructurally. During spermatogenesis, some germinal cysts in the seminal lobules were found to contain spermatocytes, which were provided with irregularly shaped nuclei, doughnut-shaped mitochondria, and atypical intercellular bridges with multiple disk-like cisternae. In addition, many cysts containing binuclear spermatids were observed in the testis. Within the condensed chromatin of the paired nuclei of the aberrant spermatids, highly electron-dense granules occurred, becoming the core of successively developing chromatin globules. The chromatin globules increased in size, resulting in an enlargement of the paired nuclei. These cells were finally released from the cyst into the lumen of the seminal lobules and underwent further degeneration, thus appearing as characteristic ‘spermatid masses’ in the mature testes.
    • Article

      Ultrastructure of the anterior intestinal epithelia of the orange-spotted grouper Epinephelus coioides larvae under different feeding regimes 

      YH Primavera-Tirol, RM Coloso, GF Quinitio, R Ordonio-Aguilar & LV Laureta Jr. - Fish Physiology and Biochemistry, 2014 - Springer Verlag
      Enterocytes of the anterior to midsection of the intestine in grouper Epinephelus coioides larvae were compared among different treatments: unfed to the point-of-no-return (PNR), fed natural food only, and co-fed natural food and artificial diet. On day 3, the nutritional condition of unfed grouper larvae regressed with its reduced enterocyte heights which were further degraded on day 4, the PNR, when all the enterocytes were in advanced stages of apoptosis. The apoptosis appeared to be internally directed via the mitochondria. Among day 3 fed larvae, enterocyte heights of those fed artificial diet did not differ from those fed natural food only. Dietary phospholipid deficiency was indicated in larvae co-fed artificial diet on day 3 with an unusually large chylomicron opening into the inter-enterocyte space, and on days 6 and 33 by intestinal steatosis. On day 19, scant to absent lipid droplets in enterocytes of larvae disclosed heightened nutritional requirement preparatory to metamorphosis. As observed in unfed day 3 and premetamorphic day 19 E. coioides, larvae undergoing critical periods and starvation during development employ apoptosis to dispose of degenerated enterocytes that are phagocytosed by adjacent healthy enterocytes without causing inflammatory distress. Upon metamorphosis, grouper larval gut develops better immunity fitness with eosinophilic granule cells observed in the intestinal epithelia of day 33 larvae. Future studies on grouper larval nutrition may consider the appropriate dietary phospholipid levels and larval competence to biosynthesize highly unsaturated fatty acid from linoleic acid vis-à-vis the use of plant ingredients in artificial diet formulations. In vivo challenge tests may validate appropriate dietary nutrient supplementation and lead to better feed formulation, matching the varying energetic demands and digestive capacities of developing E. coioides larvae.