Now showing items 3051-3070 of 3209

    • 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.
    • Article

      The ultrastructure of the hepatocytes of the giant seaperch, Lates calcarifer (Bloch) (Pisces: Centropomidae), during starvation and refeeding with different diets. 

      EM Avila - Asian Marine Biology, 1986 - The Marine Biological Association of Hongkong
      Three groups of immature seaperch acclimated in the laboratory on a mixed commercial pellet and minced trashfish diet were starved for 30 days. Thereafter, the first group was starved for 7 more days, the second was refed with commercial pellets, and the third with trashfish. Through transmission electron microscopy, it was found that after the acclimation period the hepatocytes of Lates calcarifer were primarily lipid-storing. Upon starvation, the following modifications in the hepatocytes were evident: decrease of lipid reserves, hepatocyte shrinkage, mitochondrial swelling, dilation of the cisternae of the rough endoplasmic reticulum (RER), and the presence of lysosomes. Among the refed fish, only the hepatocytes of those which were given trashfish recovered from the injury. Recovery was indicated by the restitution of the morphology of the mitochondria, development of parallel stacks of RER, increase in lipid and glycogen, and the distinct compartition of the hepatocytes.
    • magazineArticle

      The UN World Charter for Nature 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1994 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Conference paper

      An uncertain future for seahorse aquaculture in conservation and economic contexts 

      ACJ Vincent & HJ Koldewey - In JH Primavera, ET Quinitio & MRR Eguia (Eds.), Proceedings of the Regional Technical Consultation on Stock Enhancement for Threatened Species of International Concern, Iloilo City, Philippines, 13-15 July 2005, 2006 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Book chapter

      Understanding community-based aquaculture through participatory approaches 

      RF Agbayani - In Handbook for Regional Training on Community-Based Aquaculture for Remote Rural Areas of Southeast Asia, 2008 - Southeast Asian Fisheries Development Center
    • Conference paper

      Unified provincial fisheries law enforcement of ordinance of Camarines Norte focusing on mud crab 

      EA Estanislao - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Due to overfishing and widespread coastal habitat degradation, the Province of Camarines Norte passed a provincial fisheries law enforcement known as the Unified Provincial Fisheries Law Enforcement Ordinance of Camarines Norte (UPFLEON) (P.O. 50-10). Given emphasis in the paper is the banning in the collection and possession of less than 1.0 cm juvenile crabs.
    • magazineArticle

      Unifying the art, science and business of aquaculture through the information resources and services of SEAFDEC Aquaculture Department Library 

      SB Alayon, DL Superio, JG de la Peña & ES Nemiz - Fish for the People, 2013 - Secretariat, Southeast Asian Fisheries Development Center
      Established in 1973 in Tigbauan, Iloilo, Philippines, the Aquaculture Department (AQD) is one of four Departments of the Southeast Asian Fisheries Development Center (SEAFDEC). AQD is mandated to conduct scientific research to generate aquaculture technologies relevant and appropriate for the region; develop human resources; and produce, disseminate and exchange information on aquaculture. AQD is committed to sustainable development and the responsible stewardship of aquaculture resources through science-based research and the promotion of appropriate technologies and information relevant to the Southeast Asian region (SEAFDEC/AQD, 2009). The need to disseminate AQD’s research results is as important as the conduct of research in fisheries and aquaculture as referred to in the Code of Conduct for Responsible Fisheries (Wilkinson and Collins, 2007). In cognizance of the role that AQD should play with respect to its function of disseminating and exchanging information on aquaculture, the AQD Library was established to support the information needs of AQD scientists and staff. In addition, the Library also provides services to visiting researchers, local and international trainees and students, as well as the diverse users from AQD’s partner institutions. During the strategic planning workshop conducted by AQD in 2009, one of the goals identified was for AQD to strengthen the capacities of the aquaculture sector. Matching with such goal, the Library and Data Banking Services Section of the Training and Information Division identified its information dissemination and services target for 2012. Primarily, AQD Library aims to improve accessibility to archived and updated information, and to create a digital library collection of AQD publications and documents. In keeping up its goal of providing quality, current and relevant information, the Library continues to avail of quality print and non-print information resources, to ensure that it keeps abreast of the advancements in aquaculture and fulfil the diverse information needs of users. The Library also introduces innovations in its services with the purpose of unifying the art, science and business of aquaculture, and strengthens its local and international linkages for efficient sharing of knowledge and resources.
    • magazineArticle

      Update on tilapia 

      W Yap - SEAFDEC Asian Aquaculture, 1998 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • magazineArticle

      Updates in the Philippines: Where are the captive milkfish breeders? 

      AC Emata - SEAFDEC Asian Aquaculture, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A map is provided showing the location of milkfish rearing facilities in the Philippines. Most of the 17,443 milkfish broodstocks are located in central Philippines. A table shows details as to the rearing facility (cage, pen, pond, tank), number of broodstocks, and age. There are 13,420 broodstocks in ponds; 2,081 in cages; 842 in tanks, and 1,100 in pens. The youngest is 3 years, the oldest 23 years old.
    • Conference paper

      Updates on the larviculture of mud crab at SEAFDEC/AQD 

      ET Quinitio, JJDC Huervana, JC Virgula & FD Parado-Estepa - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Although the mud crab (Scylla serrata) hatchery technology has been developed, issues such as high cost of production due to the need for additional facilities and labor for natural food culture, inconsistent survival rate at megalopa stage due to Molt Death Syndrome (MDS), and disease due to luminescent bacteria (Vibrio spp.), remain to be addressed. Refinements on the existing mud crab larviculture technology were done to address these problems.

      Poor nutrition, low water temperature and application of prophylaxis during the zoea l stage have been identified as possible causes of MDS. Six shrimp formulated diets (FD) were tested, and 3 of these proved to be suitable for mud crab larvicuture. Larval performance was compared using the 3 diets + natural food (NF, rotifers and Artemia) and NF alone as control. No significant difference was noted in the survival among the 4 treatments, although BP Nippai fed larvae had higher values. Lesser occurrence of MDS was observed in all the larvae fed FD+NF. Three mud crab larval diets with various attractants (squid, annelids, and squid + annelids) were also formulated and fed to the larvae. Results showed no significant difference among the 3 diets. The results of another experiment investigating the effects of the reduction of natural food showed that larvae fed 50% NF + 50% FD and 75%NF + 25% FD had higher survival compared to those fed 75% AD +25% NF and no NF at all. The results indicate that the larvae cannot survive with formulated diet alone. It has been observed that frequency of antibiotic application can be reduced to every 5 days if good quality mud crab larvae are used. Formalin stress test proved to be a reliable method to determine the quality of a batch of newly hatched zoeae. All prophylactic treatments are stopped when megalopae reach the benthic stage.

      To accelerate the dissemination of science-based mud crab hatchery technology to industry stakeholders, SEAFDEC/AQD entered into an agreement with private hatchery operators, State Universities and Colleges, and Local Government Units on giving assistance during initial hatchery operations. Technicians were given free training, followed by in-situ hatchery operations with assistance from SEAFDEC/AQD with the funding from PCAARRD-DOST. Crablets are now being produced by the collaborators. Increase in the production of hatchery-reared crablets will eventually reduce the dependence on wild-sourced mud crab seed stock for farming.
    • Conference paper

      Updates on the nervous necrosis virus and the koi herpesvirus in Southeast Asia 

      GD Lio-Po - In Proceedings of the 1st International Congress on Aquatic Animal Health Management and Diseases, 27-28 January 2009, 2009 - Veteran Council I.R.IRAN
      In Southeast Asia, the Viral Nervous Necrosis (VNN) or Viral Encephalopathy and Retinopathy (VER) and the Koi herpesvirus (KHV) infection are currently economically-important diseases of fishes. The VNN affects groupers (Epinephelus akaara, E. coioides, E. tauvina, E. fuscogutatus, E. septemfasciatus, E. malabaricus, E. moara and Cromileptes altivelis), Asian sea bass (Lates calcarifer), mangrove red snapper (Lutjanus argentimaculatus) and milkfish (Chanos chanos) in Thailand, Taiwan, Indonesia, Brunei, Malaysia, Singapore, Philippines and Vietnam. The Piscine nodavirus of the genus Betanodavirus, genotype red-spotted grouper nervous necrosis virus (RGNNV) is predominantly involved. Research on fish species pathogenicity, optimum temperature, cell susceptibility, organ predeliction, pathology, virus reservoirs, experimental infection, vaccination and diagnosis have been reported. The Koi herpesvirus (KHV) infection causes significant mortalities in common carp (Cyprinus carpio carpio), koi carp (Cyprinus carpio koi) and ghost carp (common x koi cross, Cyprinus carpio goi). Outbreaks have been reported among koi in Hongkong in 2001; common carp in Indonesia, in 2002; koi in Taiwan in 2002; and common carp in Japan, in 2003. A dramatic spread of the disease was subsequently observed among most prefectures in Japan, with outbreaks that eventually involved koi carp. In Thailand, KHV was first diagnosed in March 2005 while in Singapore, in Sept 2005. By Feb 2006, two batches of Thai koi exported to Singapore, tested KHV PCR positive from which the virus was successfully isolated on KF-1 cells. In Malaysia, no KHV outbreak was reported but the presence of the virus was detected among koi carp exported to UK in 2000 and in 2001. In 2004, koi carp in Malaysia tested positive for KHV by nested PCR. To date, annual active surveillance of the virus in Cambodia, Lao PDR, Myanmar, Philippines and Vietnam from 2004 to 2008 showed these countries are free of KHV. Recent developments on research of KHV focused on pathogenicity, cell line susceptibility, fish size susceptibility, predilection to fish organs, persistence in fish, vaccine development and application, surveillance and gene sequence analyses of KHV strains. The extensive international trading of live ornamental koi fish has largely contributed to the global spread of KHV. Hence, KHV was recently added to the list of notifiable diseases to the World Organisation of Animal Health or the Office International des Epizooties (OIE).
    • Conference paper

      Updates on the seed production of mud crab 

      ET Quinitio, FD Parado-Estepa, JJ Huervana & MR Burlas - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Widespread interest in mud crab species is increasing because these are highly prized both in domestic and export markets. Among the three mud crab species commonly found in the Philippines, Scylla serrata, S. olivacea, and S. tranquebarica, S. serrata is preferred by farmers because it is larger and less aggressive than the other species. Likewise, S. serrata is the most widely distributed species in the Indo-west Pacific region.

      Hatchery-produced seedstock are presently used by some crab farmers in their grow-out operations. In the hatchery phase, feeding mud crab larvae with shrimp formulated diets and natural food was found to reduce the occurrence of molt death syndrome, one of the major problems in seed production. Larvae given 25% formulated diet (FD) + 75% natural food (NF; rotifers and Artemia) and 50% FD + 50% NF showed better performance than those larvae fed 100% FD, 100% NF and 75% FD + 25% NF indicating that usage of natural food, especially the expensive Artemia, can be reduced. Since the early crab instar (C) produced in the hatchery need to be grown further before stocking in grow-out ponds, two phases of nursery culture have been developed. C1-2 are grown to 1.5-2.0 cm carapace width (CW) size in the first phase and further grown to 3.0-4.0 cm CW in the second phase. Nursery rearing is done in net cages installed in ponds for easy retrieval. A combination of mussel or trash fish and formulated diet is used as feed.

      Domestication of the mud crab S. serrata as a prerequisite to selective breeding has been done at SEAFDEC/AQD. Likewise, defining criteria for the determination of quality of newly hatched zoeae for stocking in the hatchery was initiated. Newly hatched zoeae were subjected to starvation and stress test using formalin. Starvation failed to elicit responses that were significantly different between the good and poor quality larvae hence it is not suitable for larval quality evaluation. Based on three-year data, the formalin stress test gave mean cumulative mortalities of 2.38±0.32, 8.24±0.88, 20±1.58 in good quality larvae, and 43.74±2.39 while 22.93±4.19, 63.68±7.17, 84.29±3.88 and 97.65±1.06 for poor quality larvae at 0 (control), 20, 30 and 40 ppm formalin, respectively. As formalin level increased, cumulative larval mortality also increased regardless of the quality of the larvae. Formalin stress test proved to be a reliable method to determine whether a batch of newly hatched zoeae was of good or poor quality.
    • Article

      Uptake and depuration of mercury in the green mussel, Perna viridis Linnaeus (Bivalvia: Mytilidae) 

      NC Rosell - Philippine Journal of Science, 1985 - Science and Technology Information Institute
      P. viridis were exposed to 3.6 ppb, and 100 ppb mercury. The mussels were also fed with algae that had been precontaminated with mercuric acetate to give a final mercury concentration of 10 ppb. Mercury bioaccumulation appears to be a function of time and concentration and is manifestly enhanced by the presence of mercury-contaminated food organisms.

      The pattern of mercury tissue distribution after 30 days exposure was found to be as follows: gills > visceral mass > mantle. Depuration is a slow process. The animals failed to purge themselves of the total amount accumulated in 45 days. Smaller mussels were observed to accumulate mercury faster than the larger ones. The Tolerance Limit Test (TLm) showed a mean mercury tissue concentration of 9,890 ppb wetweight after 65 hours exposure to 1.0 mu g Hg mL-1.
    • Article

      Uptake and elimination of inorganic mercury and selenium by minnows Phoxinus phoxinus 

      MLA Cuvin & RW Furness - Aquatic Toxicology, 1988 - Elsevier
      Minnows were kept in aquaria containing filtered water dosed with measured amounts of mercury as mercuric chloride and selenium as sodium selenate. Fishes exposed to selenium in combination with mercury showed significantly higher survival rates than those kept in tanks containing mercury alone. A 2 to 1 selenium to mercury molar ratio proved to be most effective in reducing mercury toxicity. The presence of selenium tended to increase the uptake of mercury from the water. There was no observed difference in the rate of mercury elimination in the presence or absence of selenium. These results suggest that the observed protective effect of selenium against the toxicity of mercury does not involve reduction of mercury uptake or enhancement of mercury elimination. The presence of mercury did not significantly affect selenium uptake. However, selenium elimination was reduced in the presence of mercury, suggesting that a mercury-selenium complex is formed.
    • Article

      Uptake and elimination of iodine-131 by the freshwater clam Corbicula manilensis Philippi from water 

      MLA Cuvin & RC Umaly - Natural and Applied Science Bulletin, 1988 - College of Arts and Sciences, University of the Philippines
      Whole body uptake of Iodine-131 by the freshwater clam, Corbicula manilensis, from contaminated water was followed using NaI scintillation counter. The bioaccumulation factor (BF) exclusive of shell was 5.44. The degree of bioaccumulation of I-131 by the different tissues is as follows: visceral remains > gills > gut > gonads > mantle > muscle > foot. The specific activities of the different tissues corresponded with their BF values. The relative distribution of I-131 in the different tissues was generally proportional to the weight ratio of each tissue. Elimination studies gave the effective half-life, Te0.5, of 4.5 days. Estimation of Te0.5 in the different tissues gave the following values: 12 d (mantle), 3.9 d (gonad and muscle), 3.6 d (gut), 3.4 d (gills), 2.4 d (foot) and 1.9 d (visceral remains).
    • Article

      Uptake and some physiological effects of mercury on water hyacinth, Eichhornia crassipes (Mart) Solms. 

      RA Tabbada, PE Florendo & AE Santiago - Biotropia, 1990 - SEAMEO
      The uptake and growth effects of mercury (Hg) on Eichhornia crassipes under field conditions and with lakewater as cultural medium were investigated. Absorption of the heavy metal increase with higher levels of Hg in the culture solution. Roots of the heavy metal than the leaves. The addition of 1 and 2 ppm of Hg into the culture medium was not toxic but significantly reduce fresh matter production, root elongation, ramet formation and total chlorophyll content of mature leaf blades during a four-week culture period. The results strongly suggest a beneficial role of the plant, long considered as a noxious weed, as a bioaccumulator of Hg in polluted lakes.
    • Conference paper

      Urease activity in soybean meal: effect on its nutritional quality and on growth and survival of Penaeus monodon juveniles. 

      MN Bautista-Teruel & PF Subosa - 1998 - International Foundation for Science
      Based on the results of a survey conducted on the urease activity (UA) in commercial shrimp feed containing soybean meal (SBM) (0.00-29. 70 ppm UA), a study was carried out to determine the effects of different heat treatments on the UA, and on the nutritional quality of SBM. The effect of these heat treated SBMs when incorporated into shrimp diet on the growth and survival of Penaeus monodon juveniles was likewise tested. Various levels of UA in SBM were obtained with different heat treatments. Six practical diets were formulated and contained 0.00 (SBM heated at !20°C for 20 min); 0.50 (SBM heated at 60°C for 160 min); 4.0 (SBM heated at 60°C for 80 min); 8.0 (SBM heated at 60°C for 40 min); 11.0 (SBM heated at 60°C for 20 min) and 22.0 ppm UA (without heating). These diets were fed to P. monodon (average weight = 4.24±0.10 g) juveniles for a period of 60 days. Results showed that protein quality in terms of amino acid content of SBM was not significantly affected by the different heat treatments. Weight gains of shrimps fed diets with 8.0, 11.0, 25.0 ppm UA were significantly lower than those fed other diets. Survival of shrimps was lowest with diets containing unheated SBM, but this was not significalltly different from those heated at 60°C. Heat treatment of SBM at 120°C is adequate to be an effective ingredient in shrimp diets.
    • Article

      The use of a Visual Implant tag to monitor the reproductive performance of individual milkfish Chanos chanos Forsskal 

      AC Emata & CL Marte - Journal of Applied Ichthyology, 1992 - Blackwell Publishing
      Nine-year old milkfish (3.8 kg., average body weight) were individually marked with Visible Implant (VI) tags to monitor their reproductive performance following hormonal induction. All tags were retained after one year; only 5 out of 64 tags were not readable due to improper implantation. The advantages of using VI tags include: less tagging time (less than one minute), high retention rate, longer retention, infection-free, and easily readable.
    • Article

      Use of Acadian marine plant extract powder from Ascophyllum nodosum in tissue culture of Kappaphycus varieties 

      AQ Hurtado, DA Yunque, K Tibubos & AT Critchley - Journal of Applied Phycology, 2009 - Springer Verlag
      Three varieties of Kappaphycus alvarezii (Kapilaran, KAP), Tambalang purple (PUR), Adik-adik (AA), and one variety of Kappaphycus striatum var. sacol (green sacol (GS) were used to determine the efficiency of Acadian marine plant extract powder (AMPEP) as a culture medium at different concentrations, for the regeneration of young plants of Kappaphycus varieties, using tissue culture techniques for the production of seed stock for nursery and outplanting purposes for the commercial cultivation of carrageenophytes. A shorter duration for shoot formation was observed when the explant was treated with AMPEP + Plant Growth Regulator (PGR = PAA + zeatin at 1 mg L−1) compared to AMPEP when used singly. However, four explants responded differently to the number of days required for shoot formation. The KAP variety took 46 days to form shoots at 3–4 mg L−1 AMPEP + PGR; while PUR required 21 days at 3–5 mg L−1 AMPEP and 3–4 mg L−1 AMPEP + PGR. AA required 17 days at 3–5 mg L−1 AMPEP and AMPEP + PGR; and GS 25 days at 1 mg L−1 AMPEP + PGR. It was observed that among the four explants used, PUR and AA initiated shoot formation with the use of AMPEP only at higher concentrations (3–5 mg L−1) after a shorter period. Only PUR responded positively to ESS/2 for shoot initiation. The use of AMPEP alone and/or in combination with PGR as a culture medium in the propagation of microplantlets using tissue culture technique is highly encouraging.