Now showing items 1-20 of 3186

    • Article

      Gonadal response of juvenile protogynous grouper (Epinephelus fuscoguttatus) to long term recombinant follicle-stimulating hormone administration 

      P Palma, J Nocillado, J Superio, EGdJ Ayson, F Ayson, I Bar & A Elizur - Biology of Reproduction, 2018 - Oxford University Press
      The role of follicle stimulating hormone (FSH) in the gonadal development of protogynous hermaphroditic grouper (E. fuscoguttatus) was investigated. Recombinant giant grouper (E. lanceolatus) FSH (rggFSH) was produced in yeast. Its receptor binding capacity and steroidogenic potency were confirmed in vitro. Weekly injections of rggFSH to juvenile tiger grouper for 8 weeks (100 μg/kg body weight, BW) resulted in significantly larger and more advanced oocytes (cortical alveolar stage vs. primary growth stage in control). Sustained treatment with rggFSH (20 to 38 weeks at 200 μg/kg BW) resulted in significant reduction in gonad size, degeneration of oocytes and proliferation of spermatogonial cells, indicative of female to male sex change. Gene expression analysis showed that, while initiating female to male sex change, the rggFSH significantly suppressed the steroidogenic genes cyp11b, cyp19a1a and foxl2 which restrained the endogenous production of sex steroid hormones thus prevented the differentiation of spermatogonial cells. Expression profile of sex markers dmrt1, amh, figla and bmp15 suggests that the observed sex change was restricted at the initiation stage. Based on these results, we propose that the process of female to male sex change in the protogynous grouper is initiated by FSH, rather than sex steroids and likely involves steroid-independent pathway. The cortical alveolar stage in oocyte development is the critical point after which FSH-induced sex change is possible in grouper.
    • Article

      Immunization regimen in Asian sea bass (Lates calcarifer) broodfish: A practical strategy to control vertical transmission of nervous necrosis virus during seed production 

      R Pakingking Jr., EG de Jesus-Ayson, O Reyes & NB Bautista - Vaccine, 2018 - Elsevier
      Outbreaks of viral nervous necrosis (VNN) in Asian sea bass (Lates calcarifer) at the larval stages via vertical transmission of nervous necrosis virus (NNV) from asymptomatic broodfish remain as a major deterrent during seed production. A five-year study was conducted to produce NNV-specific-free sea bass broodfish reared in land-based tanks through an annual immunization regimen with the formalin-inactivated NNV. We primarily immunized (intraperitoneal injection) sea bass juveniles (5 g) and monitored the neutralizing antibody (Nab) titers in the sera of these fish at scheduled intervals post-immunization. Nab titers in the sera of immunized fish peaked at Month 2 (titer: 1:4480 ± 1185) but thereafter gradually declined and significantly dropped (1:260 ± 83) at Month 12 post-primary immunization. Booster immunization of these fish at Month 12 post-immunization led to abrupt increases in Nab titers in booster immunized (B-Im) fish at Month 1 (1:12800 ± 6704) but thereafter declined and dropped at Month 12 (1:480 ± 165) post-booster immunization. The annual booster injections with the inactivated vaccine or L-15 (Unimmunized [U-Im]) were consecutively conducted for 4 years until the fish became sexually mature. Mature fish from both groups were successively induced to spawn twice (1-month interval) via intramuscular injection with luteinizing hormone-releasing hormone analogue (LHRH-a; 100 µg/kg BW). NNV was not detected by RT-PCR in oocytes and milts, and spawned eggs of B-Im fish. In contrast, oocytes and milts, and spawned eggs of U-Im fish were NNV positive. Spawned eggs of B-Im broodfish exhibited Nab titers ranging from 1:192 ± 34 to 1:240 while such was not detected (<1:40) in eggs of U-Im fish. Taken together, current data clearly demonstrate that annual immunization regimen with inactivated NNV vaccine is a pragmatic approach for sustaining immunocompetent sea bass broodfish reared in land-based tanks and circumvent the risk of vertical transmission of NNV from asymptomatic broodfish to their offspring under stress of repetitive spawning.
    • Article

      Limit of colour vision in dim light in larvae of the giant freshwater prawn Macrobrachium rosenbergii 

      G Kawamura, TU Bagarinao, ASK Yong, AB Faisal & LS Lim - Fisheries Science, 2018 - Springer Verlag
      Colour vision depends on sufficient ambient light and becomes ineffective at a particular low light intensity. It is not known how decapod crustaceans see colour in dim light. In the present study we investigated the colour vision threshold in larvae of the giant freshwater prawn Macrobrachium rosenbergii in a tank under natural illumination. Plastic beads of different colours (blue, red, yellow and white) in various combinations were suspended in the tank. The larvae swam straight toward the beads and gathered around them. The number of larvae was highest on the blue and white beads. The luminance in the tank was then gradually decreased by covering it with different numbers of layers of black cloth, and the response of the larvae to the beads was video-recorded under infrared illumination. The preference for blue and white beads remained manifest as the luminance was reduced from 418 to 0.07 cd/m2, but not at 0.02 cd/m2, indicating a colour vision threshold between 0.07 and 0.02 cd/m2. The larvae have apposition compound eyes with large optical parameters, comparable to those of apposition eyes of nocturnal insects, which presumably capture more light and show enhanced sensitivity, enabling the larvae to see colour in dim light.
    • Article

      Characterisation of Vibrio isolates recovered from the eyes of cage-cultured pompano (Trachinotus blochii) infested with caligid parasites (Lepeophtheirus spinifer) 

      R Pakingking Jr., NB Bautista, D Catedral & EG de Jesus-Ayson - European Association of Fish Pathologists Bulletin, 2018 - European Association of Fish Pathologists
      Exophthalmia was documented among sea cage-cultured pompano (Trachinotus blochii) broodstocks with caligid parasite (Lepeophtheirus spinifer) infestation in the Philippines. Following sequencing, and based on the results of both diagnostic investigations and infection experiments, V. harveyi likely had a role in the reported exophthalmia cases, and this was initiated by L. spinifer infection.
    • Article

      Disaster management practices of academic libraries in Panay island, Philippines: Lessons from typhoon Haiyan 

      DL Superio, SB Alayon & MGH Oliveros - Information Development, 2018 - SAGE Publications
      A disaster management plan is essential because it can guide library personnel on what to do in a critical time. Using an eight-part survey instrument, this paper documents the impact of Typhoon Haiyan on 22 academic libraries in Northern Panay, Western Visayas, Philippines and the disaster management practices that were implemented. The results revealed that although the majority of the libraries do not have a disaster management plan, they all had common disaster management practices that enabled them to save parts of their collections. Moreover, the study revealed that librarians lacked knowledge and skills on disaster management. This paper was presented at the 40th International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC) Annual Conference, Noumea, New Caledonia, September 14–18, 2014.
    • Article

      Quality assessment of newly hatched mud crab, Scylla serrata, larvae 

      ET Quinitio, JJ dela Cruz-Huervana & FD Parado-Estepa - Aquaculture Research, 2018 - Wiley
      Starvation and exposure to formalin were investigated as possible stress tests for evaluating the quality of mud crab, Scylla serrata, larvae. For the starvation stress test, newly hatched zoeae stocked in 150-ml containers were either starved or fed rotifers. Similarly, newly hatched zoeae were stocked in containers with seawater of 0 (control), 20, 30 and 40 mg/L formalin for the formalin stress test. The zoeae from the same batches were used for seed production to monitor their performance and validate the results of stress tests. Starvation was found to be unsuitable for larval quality evaluation. However, the impact of initial food deprivation on the newly hatched larvae indicates that feeding immediately after hatching is necessary for mud crab larvae. Exposure of larvae to 40 mg/L formalin for 3 hr appeared to be a reliable and practical method for larval quality assessment as the survival of larvae in the mass production tanks validated the classification of good and poor quality batches in the stress tests. On this basis, a hatchery operator can decide which batch should be cultured further. Finally, there appears to be a link between the quality of larvae and the performance at the megalopa and early juvenile crabs.
    • Book

      Biology and hatchery of mangrove crabs Scylla spp. 

      ET Quinitio, FD Parado-Estepa & JJ dela Cruz-Huervana - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 34
      This manual includes the biology of crab (Scylla serrata, S. tranquebarica, and S. olivacea), and describes principles and procedures for spawning the mature crabs and rearing the zoea to ‘fly’ size crabs. It focuses on the hatchery rearing of S. serrata as the farming of this species is more economically viable than the two other species. The techniques may be modified depending on the conditions or problems encountered in a specific site.
    • Report

      SEAFDEC/AQD Highlights 2017 

      Southeast Asian Fisheries Development Center, Aquaculture Department - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
      SEAFDEC/AQD Highlights 2017 is SEAFDEC/AQD’s annual report updating on its accomplishments and progress for the year 2017.
    • Article

      Larval rearing of mud crab (Scylla): What lies ahead 

      K Waiho, H Fazhan, ET Quinitio, JC Baylon, Y Fujaya, G Azmie, Q Wu, X Shi, M Ikhwanuddin & H Ma - Aquaculture, 2018 - Elsevier
      The increasing global demand for mud crabs (genus Scylla) and threats to the wild populations highlight the urgency of fully rearing them in captivity. Despite considerable progress in mud crab production, most crab farms still rely heavily on wild-caught crablets and juveniles while the low and inconsistent success rates of larviculture remain as the main bottleneck impeding the development of mud crab aquaculture. Over the years, numerous studies have been conducted to determine the optimum larval rearing parameters, the ontogenic changes in digestive function and feeding behaviour, and the diets for different larval stages. These data, however, are dispersed and not summarised to inform culture practices. This review provides an update on the current progresses and to pinpoint the gaps in knowledge regarding mud crab larval rearing. We include all four mud crab species under the genus Scylla, i.e. Scylla serrata, Scylla olivacea, Scylla tranquebarica and Scylla paramamosain. Knowledge compiled in this review serves as an important guideline for prospective mud crab larviculture. Future research should gear towards filling in the gaps in our knowledge to advance mud crab larval rearing, thus fully incorporating mud crab into the aquaculture sector.
    • Article

      Dietary onion or ginger modulates the stress response and susceptibility to Vibrio harveyi JML1 infection in brown-marbled grouper Epinephelus fuscoguttatus juveniles 

      EC Amar, MJS Apines-Amar & JP Faisan Jr. - Journal of Aquatic Animal Health, 2018 - American Fisheries Society
      Onion Allium cepa and ginger Zingiber officinale have health‐promoting properties that qualify them as functional foods. The effect of repeated acute stressors was examined in juvenile Brown‐marbled Grouper Epinephelus fuscoguttatus that were fed four diets supplemented with onion at 1.8%, ginger at 1.8%, vitamin C at 0.86%, and β‐glucan at 0.8% of the diet. The non‐supplemented diet served as the control. After 12 weeks of feeding, fish were exposed to stressors and were experimentally infected with a fish pathogen, the bacterium Vibrio harveyi JML1. After repeated exposure to hypoxia, cortisol levels rose significantly in the non‐supplemented fish compared to those fed onion, ginger, β‐glucan, or vitamin C. Within groups, postexposure cortisol levels in the onion‐, ginger‐, and vitamin C‐fed fish did not change relative to pre‐stress levels, whereas significant increases in poststress values were observed in the control and β‐glucan groups. The net cortisol increase was also significantly greater in the non‐supplemented group compared to the supplemented groups. The net cortisol increase did not vary among the supplemented groups except that the β‐glucan‐fed group exhibited a higher net increase than the onion‐fed group. Similarly, repeated acute exposure to osmotic stress significantly increased the plasma cortisol level in the non‐supplemented group compared to groups that received supplements; no differences were found in the supplemented groups except the β‐glucan group. Within groups, significant increases in poststress values relative to pre‐stress levels were found only in the control and β‐glucan groups. Repeated acute exposure to hypoxia significantly increased cumulative mortality in the control group compared to the supplemented groups (except the β‐glucan group), whereas repeated exposure to acute osmotic stress significantly increased cumulative mortality only in the control group 10 d after infection with V. harveyi JML1. Based on our collective results, most of the supplemented groups performed better than the control, but the best supplements were onion and ginger in terms of enhancing stress tolerance and increasing survival of Brown‐marbled Grouper upon infection with V. harveyi JML1.
    • Article

      Low ph water impairs the tactile sense of the postlarvae of the giant freshwater prawn Macrobrachium rosenbergii 

      G Kawamura, T Bagarinao, ASK Yong, SN Noor & LS Lim - Tropical Life Sciences Research, 2018 - Penerbit Universiti Sains Malaysia
      The effect of low pH on the tactile sense of Macrobrachium rosenbergii postlarvae was determined in the laboratory by means of two behavioural assays: shelter (netting) occupancy and jumping response to touch stimuli (taps) by a glass micropipette. The postlarvae were acclimated to pH 4, pH 5, pH 6 and pH 7.5 (control) in 45 L aquaria 5−7 d before the experiments. Shelter occupancy decreased with pH and was significantly lower at pH 4 and pH 5 than at pH 6 and in the control. The jumping response instantly followed a tap 93−98% of the time in the control, pH 6 and pH 5 treatments. However, the postlarvae showed significantly lower jumping response (65%) at pH 4, indicating an impaired tactile sense. Low pH 4−5 probably degrades the chitin of the sensory setae and inhibits the surface mechanoreceptors of the prawn postlarvae.
    • Article

      Does age matter?: The information-seeking behavior of Filipino aquaculture researchers 

      DL Superio - Journal of Library Administration, 2018 - Taylor & Francis
      Findings of previous studies revealed that regardless of the objective, age does affect the information-seeking behavior of an individual. Likewise, this study found the same results. Although all of the younger Filipino aquaculture researchers preferred the Internet to begin their search process, it was found that they were more frequent library users, and more reliant on librarians than their older counterparts. Likewise, they preferred the combination of print and electronic formats when reading. Thus, they would print and save the retrieved electronic copy of information at least very often. The study is a valuable addition to the information-seeking behavior studies on Filipinos, and the first to tackle the effects of age on the information-seeking behavior of Filipino aquaculture researchers.
    • Article

      The information-seeking behavior of aquaculture researchers at the Southeast Asian Fisheries Development Center 

      DL Superio, JB Canaman, JP Jaco & ML Estember - Information Development, 2018 - SAGE Publications
      Understanding the information-seeking behavior of library patrons is essential for the library to provide quality resources and services, and to satisfy its patrons’ information needs. A quantitative research was conducted to describe the information searching and using behaviors of the Filipino aquaculture scientists, researchers and research staff at the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD). The study revealed that although the respondents find it useful to go to the library to get assistance from the librarian, and to browse and read current acquisitions related to their research, they visited the library infrequently. However, remote library services, especially email and phone services, were highly utilized. When searching for information, the Internet, mainly via search engines, was highly preferred rather than visiting the Library and using its online public access catalog (OPAC) or its databases. The combination of print and electronic formats was highly preferred when reading, rather than print only or electronic-only. The majority would print and save the retrieved electronic copy.
    • Newsletter

      AQD Matters 2018 January - February 

      RH Ledesma (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Application of poly-β-hydroxybutyrate (PHB)-based biodegradable plastic as artificial substratum in Litopenaeus vannamei culture 

      G Ludevese-Pascual, JL Laranja, E Amar, P Bossier & P De Schryver - Journal of Polymers and the Environment, 2018 - Springer
      The use of artificial substratum made out of poly-β-hydroxybutyrate (PHB) based biodegradable plastic for penaeid shrimp culture was investigated for the first time. Provision of PHB substratum consisting of PHB type P209 (Biomer, Krailling, Germany) to postlarval whiteleg shrimp Litopenaeus vannamei (106 ± 52 mg) resulted in significantly higher survival (P ≤ 0.05) of 83.6 ± 3.4% as compared to 73.9 ± 3.0% for postlarvae provided with conventional substratum consisting of polyvinylchloride (PVC) pipes. Results on final weight showed significantly higher weight (P ≤ 0.05) of 1008.2 ± 4.5 mg in postlarval whiteleg shrimp provided PHB substratum as compared to 893.4 ± 30.0 mg for postlarvae provided with PVC substratum. The trends of higher visit and preference by postlarval whiteleg shrimp on 10-day and 70-day aged PHB substrata over 10-day and 70-day aged PVC substrata suggest the importance of PHB substratum as grazing area rather than as shelter. Test conducted on water quality also showed a trend towards higher total ammonia-nitrogen (TAN) conversion from an initial concentration of 1.75 ± 0.0 mg L−1 to 0.35 mg ± 0.04 mg L−1 after 72 h with PHB substratum while using no substratum and PVC substratum lead to TAN concentrations of 1.28 ± 0.06 mg L−1 and 1.23 ± 0.10 mg L−1, respectively. Overall, this study indicates that artificial substratum consisting of PHB-based biodegradable plastic increases the quality of postlarval whiteleg shrimp and that it contributes to maintaining good water quality.
    • Article

      Parasites from the green mussel (Perna viridis Linnaeus 1758) (Mollusca: Mytilidae) of Ivisan, Capiz, Philippines 

      G Erazo-Pagador - Philippine Agricultural Scientist, 2018 - College of Agriculture and Food Science, University of the Philippines Los Baños
      This study reports the parasites found in green mussel (Perna viridis L.) from Ivisan, Capiz, Philippines. Samples were collected monthly from January to December 2009. A total of 360 samples were collected, fixed in 10% formalin in seawater solution, and processed by standard histological techniques that included staining the sections with hematoxylin and eosin (H & E). The water temperature ranged from 24 to 30°C and salinity from 18 to 23 ppt. Microscopic analysis showed that the most prevalent parasites were Nematopsis sp. occurring mostly in connective tissues (46%), metacestodes of Tylocephalum sp. in the mantle (12%), and a turbellarian (4%) and metacercariae in the mantle (4%). Based on these findings, these parasites may not yet be a problem to mussel farming as they were low and caused no apparent damage to the host.
    • Newsletter

      AQD Matters 2018 May - June 

      RH Ledesma (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 45th Anniversary Special Issue 

      RDB Dianala (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2018 July - August 

      JMV de la Cruz (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Microalgal paste production of the diatom Chaetoceros calcitrans using electrolytic flocculation method at optimum culture conditions 

      MR de la Peña, AV Franco, HP Igcasan Jr., MDGN Arnaldo, RM Piloton, SS Garibay & VT Balinas - Aquaculture International, 2018 - Springer Verlag
      The optimum culture conditions of the local strain Chaetoceros calcitrans were determined to improve biomass and reduce cost of production. Under outdoor culture conditions, higher cell density was attained when the cultures were enriched with Tungkang Marine Research Laboratory (TMRL) medium composed of cheap technical grade reagents and cultured at 25 g L−1 salinity. The cultures were lighted with two 40 W cool-white GE fluorescent tubes (24–35 μmol photon m−2 s−1). Using semi-continuous culture system under established optimum culture conditions, C. calcitrans can be re-cultured thrice and concentrated at each culture cycle using electrolytic flocculation method to produce 4.6 kg m−3 of diatom paste. The viability of concentrated C. calcitrans after 3 months of storage was comparable to live diatom cells. Simple preservation technique by low-temperature storage is convenient for storing algal concentrates for use as starter cultures and for feeding invertebrates. The paste costs USD 8.24 kg−1 inclusive of the assets and flocculation materials for culturing and harvesting the diatom, respectively. This study established the suitable conditions for mass culture of C. calcitrans and produced concentrated diatoms in paste form that is readily available for aquaculture hatcheries at a lower cost.