Now showing items 142-161 of 1070

    • Article

      Daily amount of rotifers taken by a sea bass Lates calcarifer larvae 

      H Kohno & M Duray - Philippine Journal of Science, 1990 - Science and Technology Information Institute
      The amount of rotifers consumed by a single sea bass Lates calcarifer larva per day (R) was examined by both the direct and by the satiation-digestion methods. In the direct method, R is estimated by the number of rotifers left in the larval tanks and larval density in the tanks, while in the satiation-digestion method R is estimated by the amount of rotifers found in the digestive tract of the larvae. In both methods, the amount of rotifers consumed by the larvae increased exponentially with larval growth. The relationship between the total length (TL) and the log-log plots of the maximum amount of rotifers eaten by a larva can be expressed by the following equations; R=1.799 x TL4.398 (r=0.975) for the direct method and R= 4.861 x TL3.432 (r = 0.907) for the satiation-digestion method. The relationship between TL and body wet weight (BW) can be expressed as: BW = 2.607 x 10-4 x TL3.786 (r=0.960) for larvae smaller than 6.5 mm TL and BW = 15.053 x 10-3 x TL2.855 (r = 0.916) for those larger than 6.5 mm TL.

      The index of satiation was almost the same for day 6(0-6), D-9 and D-12 (8.3-23%), higher range was observed in D-15 larvae. The index of daily feeding amount was comparatively higher in D-12 larvae compared to D-6, D-9 or D-15 larvae.
    • Article

      Daily rates of ingestion on rotifers and Artemia nauplii by laboratory-reared grouper larvae of Epinephelus suillus 

      MN Duray - The Philippine Scientist, 1994 - San Carlos Publications, University of San Carlos
      The amount of rotifers and Artemia nauplii consumed daily by the grouper Epinephelus suillus larvae was determined through examination of gut contents. The larvae (2.6 mm TL) were initially fed rotifers on day 2 and newly hatched Artemia nauplii on day 21 (9.1 mm TL). The amount of food consumed by the larvae increased with larval growth. Larvae also showed diurnal feeding pattern at day 7 (3.6 mm TL), day 14 (4.9 mm TL), day 21 (9.1 mm TL) and day 28 (11.1 mm TL). Feeding incidence increased in the evening and became zero at 2100-2200 h. Active feeding started earlier in the older larvae and satiation was between 0900-1100 hr.
    • Article

      Daily variations in plasma hormone concentrations during the semilunar spawning cycle of the gulf killifish, Fundulus grandis 

      AC Emata, AH Meier & SM Hsiao - Journal of Experimental Zoology, 1991 - Wiley-Liss
      Male and female gulf killifish, Fundulus grandis, were kept in large cages submerged in their natural habitat in the Gulf of Mexico. Gonadosomatic indices (GSI: 100 × gonad weight/body weight) and blood samples were obtained from male and female fish every 4 hours (beginning at 1600) throughout a day on 3 separate days of the semilunar cycle: at the GSI and spawning peak (July 27–28), at midcycle (August 2–3), and on a day prior to the probable spawning peak (August 9–10). Blood samples of females were assayed for cortisol, estradiol-17β (E2), progesterone, testosterone, thyroxine (T4), and triiodothyronine (T3). The daily rhythms of hormones at each of the three days during the cycle differed markedly from one another. At the spawning peak, E2 and T3 peaks occurred at 1200, testosterone and progesterone peaks were found at 2400 and the GSI and cortisol peaks were at 0400. The GSI decreased sharply at 0800 indicating a period of probable spawning. At midcycle, most hormone levels were low throughout the day and the amplitudes of the hormone rhythms were suppressed. One day prior to the spawning peak, testosterone and progesterone variations (peaks at 2400) were similiar to those found on the day of the first semilunar GSI and spawning peaks. Daily variations of other hormones, especially E2, were prominent on the day prior to peak spawning but different from those found on the day of peak GSI/spawning. In males, plasma concentrations of cortisol, testosterone, T3 and T4 also underwent daily variations that differed from one another on the 3 days of the cycle. The results clearly demonstrate that there are dramatic changes in the daily variations of plasma hormone concentrations during the semilunar spawning cycle.
    • Article

      Decapsulation of Artemia cysts: A simple technique for the improvement of the use of brine shrimp in aquaculture 

      P Sorgeloos, E Bossuyt, EM Laviña, M Baeza-Mesa & G Persoone - Aquaculture, 1977 - Elsevier
      Although it is a common practice in different disciplines of fundamental research on the brine shrimp, and despite the very interesting applications that it offers for the use of Artemia in aquaculture, the "decapsulation" technique, which removes the outer layer of the cyst shell of Artemia, is not known to shrimp and fish aquaculturists.

      The present paper describes the technology developed by the authors for the routine decapsulation of Artemia cysts. The advantages which result from the use of decapsulated cysts in aquacultural hatcheries are discussed.
    • Article

      Deep-sea farming of Kappaphycus using the multiple raft, long-line method 

      AQ Hurtado & RF Agbayani - Botanica Marina, 2002 - Walter de Gruyter
      Farming practices of Kappaphycus seaweed planters using the multiple raft, long-line method were assessed in three major cultivation areas of Zamboanga del Sur, Mindanao. Results show that this cultivation method is appropriate in deeper waters (> 10 m deep). Family labor (6–70 years old) is usually used in the selection and preparation of ‘cuttings’, unloading of newly harvested crops and drying of seaweeds, while preparation and installation of the raft, tying of ‘cuttings’ and harvesting, hired labor is needed. Though the multiple raft, long-line method of cultivating Kappaphycus is expensive (PhP 45,742 to PhP 49,785) based on a 500 m2 raft, return on investment (ROI) is high and the payback period is short. Of the three areas assessed, Maasin had the highest ROI (218%), followed by Tictauan Island (212%), and finally Taluksangay (79%). Consequently, the payback period followed the same order. Seaweed farming in these areas showed a tremendous impact on the quality life of the fisher folk and contributed a high revenue to the national economy.
    • Article

      Dehalogenase from Methylobacterium sp. HJ1 induced by the herbicide 2, 2-dichloropropionate (Dalapon) 

      NH Jing, AM Taha, RV Pakingking Jr., RAB Wahab & F Huyop - African Journal of Microbiology Research, 2008 - Academic Journals
      Heavy industrial activities and agricultural processes require consumption of many halogenated compounds, and release them continuously as pollutants into the environment. These xenobiotics show high toxicity and persistence and cause many problems to the society, soils and ground water. Microbial dehalogenases are involved in the biodegradation of many important chlorinated compounds. A bacterial strain identified as Methylobacterium sp. HJ1 is able to degrade the herbicide 2,2-dichloropropionic acid by removal of the halogen and subsequent metabolism of the product for energy. D,L-2-chloropropionate also supported good growth of the organism but 3-chloropropionate, monochloroacetate and dichloroacetate were not utilized. Cell-free extracts of the 2,2-dichloropropionate-grown bacteria converted 2,2-dichloropropionate into pyruvate with the release of two chloride ions for each molecule of pyruvate formed. This indicates the presence of dehalogenase activity in the cell-free extracts. Only 2,2-dichloropropionate and D,L-2-chloropropionate were inducers and substrates for the dehalogenase. Monochloroacetate and dichloroacetate did not serve as an inducer, whereas 3-chloropropionate was a non-substrate inducer.
    • Article

      Density dependent growth of the tropical abalone Haliotis asinina in cage culture 

      EC Capinpin Jr., JD Toledo, VC Encena II & M Doi - Aquaculture, 1999 - Elsevier
      The effects of different stocking densities on the growth, feed conversion ratio and survival of two size groups of the tropical abalone Haliotis asinina were determined. Three culture trials were conducted in net cages installed in a sheltered cove, Guimaras Province, Philippines. Trials 1 and 2 were conducted using 15–20 mm abalone juveniles for 150 days, while trial 3 was conducted using 35–40 mm abalone for 180 days. The animals were fed sufficient amounts of the red alga, Gracilariopsis bailinae (=G. heteroclada), throughout the experiment. There was an inverse relationship between growth (length and weight) and stocking density. Feed conversion ratio was not influenced by density, but was observed to be higher for larger animals. Survival was not significantly affected by density. Net cages are appropriate for culture of H. asinina. This study showed that H. asinina can reach commercial size of about 60 mm in one year. It also showed that growth of H. asinina can be sustained on a single-species diet. An economic analysis will be important in choosing the best stocking density for commercial production.
    • Article

      Detection of Vibrio penaeicida in kuruma prawn after transport 

      LD de la Peña, H Koube, T Nakai & K Muroga - Fish Pathology, 1997 - Japanese Society of Fish Pathology
      In Japan, vibriosis caused by Vibrio penaeicida usually occurs in cultured kuruma prawn (Penaeus japonicus) during summer and fall. The causative bacterium can easily be detected from overtly diseased prawns, but from apparently healthy prawns the detection rate is low. The results of the conventional isolation method of the pathogen does not seem to reflect the true carrier rate because more prawns often come into overt infection after collection-transport-acclimation procedures, although such data have not been published.

      In the present study, transport stress was given to apparently healthy prawns to verify the above phenomenon.
    • Article

      Development and characterization of nine novel microsatellite markers for the milkfish Chanos chanos 

      BS Santos, MRR Romana-Eguia, ZU Basiao & M Ikeda - Conservation Genetics Resources, 2015 - Springer Verlag
      The milkfish, Chanos chanos, is an important aquaculture resource in Southeast Asia. Using NGS data, 72 microsatellite markers were developed. PCR product confirmation using agarose gel electrophoresis allowed the identification of 24 utilizable markers. Milkfish samples (n = 48) from a hatchery stock in Palawan, Philippines were analyzed for genetic variability at the aforementioned 24 loci. Consequently, nine of these microsatellite loci were noted to have high success rate in amplification, exhibited polymorphism with 19 maximum number of alleles and no null alleles. These are the first microsatellite markers to be developed and characterized for C. chanos that will efficiently enable genetic stock delineation and monitoring as well as marker-aided genetic improvement research.
    • Article

      Development and conservation of Philippine mangroves: institutional issues 

      JH Primavera - Ecological Economics, 2000 - Elsevier
      The decline of Philippine mangroves from half a million hectares in 1918 to only 120 000 ha in 1994 may be traced to local exploitation for fuelwood and conversion to agriculture, salt beds, industry and settlements. But brackishwater pond culture, whose history is intertwined with that of mangroves, remains the major cause of loss. The paper discusses the institutional issues — aquaculture as development strategy, low economic rent of mangroves, overlapping bureaucracy and conflicting policies, corruption, weak law enforcement and lack of political will — relevant to this decline. Recommended policies are based on these institutional factors and the experiences in mangrove rehabilitation including community-based efforts and government programs such as the 1984 Central Visayas Regional Project. These recommendations include conservation of remaining mangroves, rehabilitation of degraded sites including abandoned ponds, mangrove-friendly aquaculture, community-based and integrated coastal area management, and provision of tenurial instruments.
    • Article

      Development of a method for reproducing epizootic ulcerative syndrome using controlled doses of Aphanomyces invadans in species with different salinity requirements 

      ES Catap & BL Munday - Aquaculture, 2002 - Elsevier
      Lesions typical of epizootic ulcerative syndrome (EUS) were induced in three-spot gourami, Trichogaster trichopterus, and sand whiting, Sillago ciliata, injected intramuscularly with controlled doses of Aphanomyces invadans zoospores, the fungal pathogen associated with the disease. Both species of fish exhibited chronic granulomatous response and inflammatory cells, predominantly macrophages and lymphocytes, infiltrated the muscle and skin tissues, at days 6–8 post-inoculation of 65 to 85 spores/fish. Based on the comparative granuloma counts and percentage of cellular infiltration in a sampled lesion area using image analysis, it was shown that the three-spot gouramis mounted a more vigorous response than the sand whiting. It was also observed that lesions in three-spot gouramis exhibited early signs of resolution than those in sand whiting. However, fish mortality was greater in EUS-affected three-spot gourami than in EUS-affected sand whiting. With this technique, we were able to describe and compare the sequential histopathology of EUS lesions in a freshwater (three-spot gourami) and an estuarine (sand whiting) fish species.
    • Article

      Development of a polymerase chain reaction (PCR) assay targeted to the dnaJ gene of Vibrio harveyi, a bacterial pathogen in Asian seabass, Lates calcarifer 

      CMA Caipang, RV Pakingking Jr., MJS Apines-Amar, F Huyop & NB Bautista - Aquaculture, Aquarium, Conservation and Legislation, 2011 - Bioflux
      Partial sequence of the dnaJ gene of Vibrio harveyi, which was isolated from diseased juvenile Asian seabass, Lates calcarifer was identified. The partial sequence of dnaJ gene of V. harveyi was 447 bp and shared at least 77% identity at the nucleotide level with the dnaJ gene of other Vibrios. It was distinct from the dnaJ gene of other Vibrios but was closely related with the dnaJ gene of V. rotiferianus and V. campbellii having at least 90% nucleotide identity. PCR primers targeting this gene were designed to detect the pathogen in Asian seabass. The assay was specific to V. harveyi and the limit of detection was 100 pg of genomic DNA ml-1 or 100 fg of bacterial genomic DNA in a PCR reaction. This corresponded to a sensitivity of approximately 20 genome equivalents (GE) of V. harveyi. These results indicate that the dnaJ gene is a good candidate to develop primers for the PCR assay in detecting V.harveyi in fish.
    • Article

      The development of an institutional repository at the Aquaculture Department of the Southeast Asian Fisheries Development Center, Philippines 

      SB Alayon, ES Nemiz, DL Superio, JG de la Peña & LG Pacino - Program: Electronic Library and Information Systems, 2013 - Emerald
      Purpose - This paper aims to present the experiences of SEAFDEC/AQD library staff in digitizing institutional publications and developing an institutional repository (IR). Design/methodology/approach - SEAFDEC/AQD IR or SAIR provides a reliable means for its researchers to store, preserve, share their research outputs, enable easy access to and increase the visibility of its scientific publications. The repository uses DSpace customized with some add-ons. Details on the digitization hardware and software, layout, delivery format, and persistent identifier used are provided. Findings - As of March 2012, the repository contains 771 items with 541 downloadable PDFs. SAIR had 88,287 item views, 69,249 PDF downloads and 271,978 searches. SAIR is registered to and indexed by OpenDOAR, ROAR, Google Scholar and WorldCat. It is harvested by AVANO Ifremer, BASE, Sciencegate.ch and OAIster. Initial impact based on indicators in webometrics ranking web of world repositories and research centers was presented. Reluctance to contribute to IR has been observed by the library staff among SEAFDEC/AQD researchers. Research limitations/implications - The IR can be an effective tool to promote institutional publications and those written by researchers in peer-reviewed journals and to generate higher citations through increased visibility. IR submission policy and procedures are being drafted by the library staff. Practical implications - SAIR provides free access to all in-house publications of SEAFDEC/AQD. Full-text digitized copies of fish farmer-friendly materials like books, handbooks, policy guidebooks, extension manuals, institutional reports, and newsletters can be downloaded. Originality/value - SAIR is one of only three open access institutional repositories registered in the Philippines. The paper discusses the lessons learned and issues to be addressed in developing an IR of value to other institutions considering similar projects. Future plans and further development are also presented.
    • Article

      Development of an ovarian biopsy technique in the sea bass, Lates calcarifer (Bloch). 

      LMB Garcia - Aquaculture, 1989 - Elsevier
      A convenient and rapid biopsy method for taking ovarian samples from mature sea bass (Lates calcarifer Bloch) is described. Intra-ovarian oocytes siphoned with polyethylene tubing from any region of the ovary provide a sample representative of the maturational stage of sea bass. The osmolality of a 5% phosphate buffered formalin solution is similar to that of sea bass plasma. The follicular diameter of cannulated sea bass oocytes can be measured within an hour after fixation in 5% phosphate buffered formalin without significantly deviating from the diameter of fresh oocytes.
    • Article

      Development of larval diets for milkfish (Chanos chanos) 

      IG Borlongan, CL Marte & JN Nocillado - Journal of Applied Ichthyology, 2000 - Blackwell Publishing
      This study aimed to develop nutritionally balanced and costeffective processed diets for milkfish larvae (Chanos chanos). Two larval diets (feed A and feed B) were formulated and prepared to contain 45% protein and 10% lipid. Several larval diet preparations were tried such as microbound/unpelleted (freeze-dried), microbound /pelleted (oven-dried) and microbound/flaked (drum-dried) and assessed in terms of feed particle size and buoyancy, water stability and feed acceptability. The preparation that gave the best particle size and buoyancy as well as good water stability was prepared as the microbound diet (using K-carrageenan as a binder) and flaked using a drum drier. A series of feeding experiments were conducted to determine the growth and survival of milkfish larvae reared on various feeding schemes using these processed larval diets which were fed either solely or in combination with live feed. Larvae in control treatments were reared on live foods such as Brachionus plicatilis and Artemia nauplii. Larvae were observed to ingest the diets, indicating that the feeds had suitable physical characteristics and were attractive to the larvae. The overall results of the feeding trials showed that the artificial diets could be fed to milkfish larvae in combination with Brachionus rotifers starting on day 2 or day 8, and could be fed alone starting from day 15. These promising results would reduce the dependence of milkfish larvae on live feed and would have significant economic benefits in the form of simplified milkfish hatchery procedures.
    • Article

      Development of mouth width and larval growth in three marine fish species 

      MN Duray & H Kohno - Philippine Journal of Science, 1990 - Science and Technology Information Institute
      Hatchery-bred larvae of three marine fish species, milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) were reared on rotifers and Artemia nauplii. Development of the mouth width and larval growth were monitored in the laboratory. Growth was slow on the first six days in milkfish and rabbitfish and on the first four days in seabass. Mouth width at opening was the smallest in rabbitfish (90-110 μm), followed by seabass (170-220) μm) and milkfish (180-270 μm), and the mouth width at the time when the larvae began to eat rotifers was 219 + 7.4 μm, at 82.5 h after hatching, in rabbitfish, 224 +7.9 μm, at 71 h, in seabass, and 3306 + 38.9 μm, at 125 h, in milkfish. A positive correlation between mouth width and larval growth was shown by three species studied.
    • Article

      Development of the digestive tract of milkfish, Chanos chanos (Forsskal): Histology and histochemistry 

      RP Ferraris, JD Tan & MC de la Cruz - Aquaculture, 1987 - Elsevier
      The digestive tract of the newly hatched milkfish larva is a simple undifferentiated tube. Three days after hatching, differentiation of the esophagus begins with development of mucous-secreting cells. At this time, the intestine can be distinguished from the anterior portion of the digestive tract by its tall columnar cells with centrally located nuclei and brush border with cytoplasmic projections. After 14 days, mucosal folds develop in the esophagus. In 21-day-old larvae, the stomach differentiates into the cardiac and pyloric regions while goblet cells start to develop in the intestine. In fish undergoing metamorphosis (≥ 42 days old), the mucosal cells of the cardiac stomach develop into two distinct cell types: the columnar cells which make up the folds nearest the lumen, and the cuboidal cells which constitute the gastric glands. The cardiac stomach is the only region in the digestive tract where mucus secretion is not acidic. From 3-day-old larvae up to the older stages, alkaline phosphatase is localized only at the brush border of the intestinal epithelial cells. Aminopeptidase is also found only in the brush border of enterocytes, but only in 21-day and older milkfish. Intestinal esterases are present not only in the brush border but are also diffusely distributed in the cytoplasm of enterocytes of 3-day or older fish. Esterase is also found in both the columnar and gland cells of the cardiac stomach, but only in postmetamorphic (60-day or older) fish. These morphological and histochemical changes of the gut seem to parallel dietary and habitat shifts throughout development, which encompasses life stages spent in pelagic, coastal or inland waters.
    • Article

      Development of the external genitalia of the giant prawn, Penaeus monodon. 

      H Motoh & P Buri - Bulletin of the Japanese Society of Scientific Fisheries, 1980 - The Japanese Society of Scientific Fisheries
      The present paper deals with the morphological development of the external genitalia of Penaeus monodon which will serve as a basis for future researches on the reproductive biology of this species. The petasma length is taken as the median linear distance between the anterior and posterior margins of the organ, and the thelycum length the linear distance between the anterior edge of the boss-like antero-median plate and the posterior margin of the lateral plates. A description is given of the metamorphosis of male and female genitalia of P. monodon.
    • Article

      Developmental and ecological stages in the life history of milkfish Chanos chanos (F.) 

      P Buri, VC Bañada & AT Triño - Fisheries Research Journal of the Philippines, 1981 - Fisheries Research Society of the Philippines
      Seven stages in the life history of milkfish Chanos chanos are suggested: embryonic, yolksac larval, larval, postlarval, juvenile, sub-adult and adult stages. These were based on morphological differences and on their particular ecological requirements. The latter include: behavioral pattern, food and feeding habits, and habitat requirements. Throughout the life cycle of milkfish the stronger driving force with determines particular behavioral strategies can be attributed to the evolutionary response of the organism of food distribution (availability) followed by predation pressure.
    • Article

      Developmental stages of a microsporidian parasite of the white prawn, Penaeus merguiensis de Man 1888 

      MCL Baticados & GL Enriquez - Natural and Applied Science Bulletin, 1982 - University of the Philippines
      A microsporidian parasite found to invade the ovaries of the white prawn, Penaeus merguiensis de Man, 1888, causes the whitening of the mature female gonads. Ultrastructure examination of the white ovaries reveal the presence of spores and other developmental stages of the parasite.

      The earliest stage observed is the schizont which contains a few cisternae of endoplasmic reticulum, many ribosomes and a thin plasma membrane. The next stage is the sporont characterized by a pansporoblast membrane, an increase in the amount of endoplasmic reticulum, appearance of more vesicles and of polar filament precursors. Diplokaryotic schizonts and sporonts are also found. Division of the sporonts gives rise to uninucleate sporoblasts. At this stage, the spore organelles start to form and the cell acquires a degree of plarity. The polar filament and the polar sao appear and the sporont membrane complex develops into a sporoblast wall. The sporoblast is transformed into a spore with a polar cap, posterior vacuole, polaroplast, and two laters of spore wall, the exospore and the endospore. The polar filament is a tubular structure consisting of seven coils which after the second coil taper abruptly distally.

      All these stages of development of the parasite are observed in the infected ovaries within which its life cycle is completed. A probable mode of transmission and life cycle of the parasite is presented.