Now showing items 21-40 of 3340

    • Newsletter

      AQD Matters 2019 March - April 

      JMV de la Cruz (Ed.) - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Book

      Nursery culture of tropical anguillid eels in the Philippines 

      ML Cuvin-Aralar, FA Aya, MR Romana-Eguia & DJ Logronio - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 65
      This technical publication focused on nursery production of anguillid eels from glass eels to elver using data gathered from eel farm surveys and rearing trials conducted by SEAFDEC/AQD as part of the JAIF (Japan-ASEAN Integration Fund) project on Enhancing Sustainable Utilization and Management Scheme for Tropical Anguillid Eel Resources in Southeast Asia.
    • Newsletter

      AQD Matters 2019 January - February 

      RH Ledesma (Ed.) - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Conference paper

      Risk analysis in aquaculture 

      MG Bondad-Reantaso - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The information presented in this paper were taken from several key FAO documents. The objective is to continuously raise awareness about the concept of risk analysis and its application to the aquaculture sector.

      The paper provides information in response to several key risk questions, e.g.: (1) what is risk versus hazard, (2) what is risk analysis, (3) who uses risk analysis, (4) why do countries need to be able to use risk analysis? An overview of the risks in aquaculture is also provided in terms of the process and approaches; and the different risk sectors in aquaculture.

      The paper concludes with some key points and challenges. Risk analysis is a decisionmaking tool that contributes to protecting national health and welfare. It can also contribute to sustainable aquaculture and the success of individual aquaculture businesses and operations. Risk analysis does not stand alone - it supports and is supported by other components of a National Strategy on Aquatic Animal Health. A basic strength of the risk analysis process is its flexibility - it is adaptable to almost any sector/system where risk and uncertainty occur.

      Countries will often be confronted with a lack of scientific information, both quality and quantity, to support the risk analysis process. Nevertheless, governments must often act under these uncertainties as well as make decisions in the face of a great deal of complexity, significant variability, and multiple management goals.
    • Conference paper

      FAO TCP/INT/3501: Emergency preparedness and response systems capacity and performance self-assessment survey 

      FAO - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The purpose of this survey is to obtain information on national capacity and the agencies mandated to implement emergency preparedness and response systems with respect to aquatic animal diseases. The results of this survey will help guide regional and national strategic planning with respect to improving aquatic EPR systems, thereby improving aquatic animal health more broadly and assuring adequate and rational support services to achieve sustainable aquaculture development.

      This FAO questionnaire on aquatic EPR system capacity and performance is a country level self-assessment survey with four sections: (1) general administration, (2) operational components, (3) support systems and (4) additional information.
    • Conference paper

      Country status of aquatic emergency preparedness and response systems for effective management of aquatic animal disease outbreaks in Myanmar 

      KN Oo & YY Cho - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Myanmar is one of the OIE members and the Department of Fisheries (DoF) is highly concerned with transboundary aquatic animal pathogens. Therefore, the Aquatic Animal Health & Disease Control Section has already been formed not only for field diagnostic surveys but also for border control especially at international airport and border trade areas by checking and counter checking export and import of aquatic animals and products. At the moment, the DoF is stressing an issue of some transboundary diseases for finfish such as Gyrodactylus sp., Dactylogyrus sp., Argulus sp., Trichodena sp., Streptococcus sp., Aeromonas sp., and for crustacean are MrNV/XSV and WSSV. In addition, the DoF is facing challenges with parasitic disease and bacterial disease problems due to poor water quality management at culturing fish ponds. For the prevention and control of fish diseases within the country, the DoF is issuing Health Certificates by physical and microbiological examination of fishes and fisheries products. At the same time, Quarterly report on fish disease has being regularly submitted to NACA, OIE since 1998 until now. Although the DoF has no specific law and legislation on the control of quarantine pest and disease of aquatic animal, a good aquaculture practice has been implemented and code of conduct responsible for aquaculture is being followed in the country. The aquatic health management is a challenging issue in aquaculture development. Myanmar is still needing technical assistance to improve quarantine system especially for importation and exportation of live aquatic animals. Moreover, monitoring and surveillance programs with harmonized aquatic emergency preparedness and response system are required to boost up not only for Myanmar but also for effective management of transboundary disease outbreaks in Southeast Asia.
    • Conference paper

      Emergency response to emerging disease: AHPND in shrimp 

      K Sritunyalucksana, TW Flegel, P Sithigorngul & P Wangman - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Outbreaks of acute hepatopancreatic necrosis disease (AHPND) have caused great economic losses to many shrimp producing countries in Asia since its first appearance in 2009. The causative agent was first reported in 2013 as specific isolates of Vibrio parahaemolyticus (VPAHPND) that were later found to harbor a plasmid (pVA) encoding the Pir-like binary toxin genes PirvpA and PirvpB. More recent information indicates that pVA plasmid and variants occur in many Vibrio parahaemolyticus serotypes and also in other Vibrio species such as V. campbellii, V. harveyi and V. owensii. Information on such genomic and proteomic studies of different VPAHPND isolates from different countries are reviewed. A cohort study carried out in Thailand in 2014 indicated that AHPND outbreaks account for only a portion of the disease outbreaks reported by shrimp farmers as outbreaks of early mortality syndrome (EMS). It is urgent that the etiology of the other EMS-associated mortalities be investigated and not be overlooked. It is recommended that a regional research network and surveillance program for newly-emerging or re-emerging pathogens be established to speed up the process of diagnosis and the implementation of coordinated control measures and to avoid a repeat of the EMS/AHPND scenario.
    • Conference paper

      Emergency preparedness and contingency plans to aquatic animal disease emergencies 

      MG Bondad-Reantaso - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Emergency preparedness is the ability to respond effectively and in a timely fashion to aquatic animal disease emergencies (e.g. disease outbreaks, mass mortalities). It is a key element of a National Strategy on Aquatic Animal Health and an important consideration of the Progressive Management Pathway for improving Aquaculture Biosecurity.

      The important principles, requirements and elements and components of emergency prepareness and contingency plans are briefly described. The emergency preparedness response system audit is also presented as contingency planning arrangements that can provide useful insights and guidance in improving response action to disease emergencies.

      The paper concludes that many important lessons and insights learned from dealing with disease epizootics in the early 2000 remains valid after more than two decades when the aquaculture sector continues to be plagued with emerging diseases. Past lessons and more recent experiences demonstrated the value of rapid response, reporting/notification by competent authorities, continuous development of knowledge base and capacities in diagnostics, epidemiology, risk analysis, advanced financial planning and the important roles of governments and producer sectors in co-managing disease outbreak events as they both remain the critical entities responsible for launching rapid response.

      Skills and knowledge need to be passed on to locals as they are in the frontline of any disease emergency. Share key lessons from experiences by state and non-state actors (producer and academic sectors and other important players in the value chain), the international players that launch emergency responses, disease investigations and field situation assessments as well as financial entities that support these actions need to be continued. However, we also need to do - a stock taking exercise to evaluate what worked, what did not work, what resources are needed and to understand what are the new drivers for aquatic animal disease emergence in order to move forward with the right and timely response actions to disease emergencies in aquaculture.

      Key questions remain: Are we prepared for the next outbreak/mortality event? What are the minimum preparedness and advance preparedness actions needed?
    • Conference paper

      Current status, issues, and gaps on aquatic emergency preparedness and response systems practiced by Cambodia 

      CD Khan, S Chhorn & S Thay - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A few decades ago, Cambodia was rich in both freshwater and marine fisheries resources because of its favorable geographical area. However, the fisheries resources have depleted and were unable to totally fulfill the increasing fish demands of its people. This was caused by various factors including unfavorable climate changes, increase in population, improper agricultural production practices, and other human affecting activities. In this sense, aquaculture development in Cambodia becomes increasingly important in order to reduce the fishing pressure on its natural resources which are mainly for food security and economy of Cambodian people. Aside from this, aquatic animals in the country are vulnerable to infectious aquatic transboundary diseases as a result of insufficient and low transboundary diseases monitoring capacity. Neither the official list of aquatic transboundary diseases was created nor are the emergency preparedness and response systems for effective management of transboundary disease outbreaks in Cambodia has been well-established. Nonetheless, the government fisheries officers of both central and provincial levels have conducted fish health monitoring and undertake sample collection from fish farmers since 2016 in 10 targeted provinces as funded by the European Union s Programme. Regarding the capacity of the diagnostic laboratory, officers can perform level I and II but not for all species and diseases. Level III diagnoses cannot be effectively performed yet due to the lack of facilities, skills, and knowledge. The Marine Aquaculture Research and Development Center (MARDeC) is the only main laboratory for aquatic animal health diagnosis in the country. To minimize the spread of aquatic transboundary diseases in freshwater and seawater, the Ministry of Agriculture, Forestry and Fisheries has been moving to initiate and establish policies regarding: (1) the registrations, licensing, and law enforcement; (2) the inspection of sites; (3) and the issuance of health certificate and quality seals. However, those national regulations and legislation regarding the movement of aquatic animal stocks are not yet practical or effective. Importantly, the Royal Government of Cambodia needs both technical and financial assistance. It requires an improvement, amendment, and enforcement of the regulations, laws and the standard operating procedures (SOPs). It requires laboratory capacity building and SOPs for responsible management to establish the aquatic emergency preparedness and response systems for effective management of transboundary disease outbreaks in Cambodia as well as Southeast Asia.
    • Conference paper

      Emergency preparedness and response system in Indonesia 

      MS Hastuti, Desrina & Maskur - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The Competent Authority (CA) on aquatic animal health in Indonesia is the Directorate Aquaculture Area Development and Fish Health of the Directorate General of Aquaculture (DGA) under the Ministry of Marine Affairs. CA is supported by national reference laboratories and professional human resources that are capable of fish disease diagnosis; as well as an established network with the farmers, trading association, and relevant stakeholders which are actively involved in national meetings, conferences, socialization of emerging diseases and policy and regulation. To control transboundary fish disease at national level, the government of Indonesia has a National Strategy on Aquatic Animal Health and Environment, which was developed by FAO under project of TCP/INS/3402: 2013-2015) collaboration with DGA, Ministry of Marine Affairs and Fisheries (MMAF). To strenghten the implementation of aquaculture in the country, the Indonesian Government issued President regulation Number 28 in 2017 which includes the implementation of fish health management as well as emergency response (Section VI, Article 60). To support the implementation of EPRS, Special Task Force Teams are formed by the Director General of Aquaculture.

      Stakeholders' participation is very important in the implementation of EPRS, such as a prompt report by fish farmers and extension officer to the upper level fisheries officers at district, provincial, and national level of any observed unusual mortality that indicates disease outbreaks. EPRS activities consist of emergency response on early warning (disease information, disease preventing guideline and regulation); early detection (surveillance, appointed diagnostic laboratory); and early response (collecting information, task force formation, public awareness). Standard Operational Procedures, and detection and control were done based on published scientific information available and guidelines from World Organisation for Animal Health (OIE), Network of Aquaculture Centres in Asia-Pacific (NACA) etc. Passive and active surveillance was done on major transboundary diseases in Indonesian regions including KHV, TiLV, AHPND, WSSV, and IMNV.
    • Conference paper

      Aquatic emergency preparedness and response system in Thailand 

      J Polchana - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      In Thailand, Department of Fisheries (DoF) is the competent authority for various aspects of aquatic animals including aquatic animal health. There are two principal legislation giving DoF power to apply for aquatic animal disease prevention and control measures in the country as well as import-export control; namely, Royal Ordinance on Fisheries and Animal Epidemic Act.

      DoF has two national reference laboratories for aquatic animal health, one is Aquatic Animal Health Research and Development Division (AAHRDD) for freshwater aquatic animal disease diagnosis and another is Songkhla Aquatic Animal Health Research Center (SAAHRC) for brackish water aquatic animal disease diagnosis. Both are ISO/IEC 17025 accredited laboratories. Besides, there are 19 regional laboratories of DoF located in different areas of the country. All of 21 laboratories are responsible for performing disease diagnosis service for fish farmers as well as for disease surveillance. There are a number of surveillance and control programs for aquatic animal diseases in Thailand. Passive surveillance: information can be collected from disease reporting and other sources such as scientific research, news, publications, social network, or rumor. Active surveillance: to provide assurance of disease status for trade purposes, DoF has setup nationally active targeted surveillance program for demonstrating a number of diseases free status of country or farm establishment in accordance with OIE Aquatic Animal Health Code.

      There are several farm standards in Thailand such as Good Aquaculture Practices for Hatchery of Disease Free Pacific White Shrimp, Good Aquaculture Practices for Marine Shrimp Farm, and Aquaculture Establishment for Export of Aquatic Animals. Each standard includes necessary biosecurity practices in order to prevent the introduction of pathogenic agent into or spread within or release from the farm. To control domestic movement of live aquatic animals, in normal situation, Aquatic Animal Movement Document should be gained when purchasing as it is beneficial to traceability. However if the disease free zone or disease zone is announced according to Animal Epidemic Act, all transportation of target aquatic animals or carcasses in or out of the defined zone is prohibited, unless a written permission is obtained.

      DoF had developed contingency plan for dealing with aquatic animal disease emergencies. In contingency plan, the Provincial Fisheries Officer in responsible area will act as Director of Emergency Aquatic Animal Disease Control Center while Inland Aquaculture Research and Development Center/Coastal Aquaculture Research and Development Center/AAHRDD/SAAHRC will act as disease investigator and laboratory testing. DoF maintains early warning system by supporting staff to attend the meeting and workshop where there is occurrence of new disease, regularly checking local/regional/international disease report database, communicate with competent authority of trade partner, and regularly reporting disease situation to regional and international system. For early detection system, DoF has not only supported expertise and facilities required for laboratories to diagnose different diseases but also conducted training courses for fish farmers, traders and DoF staffs to recognize signs of the listed disease and emerging disease and encouraged them for rapid reporting of the event to the nearest DoF agency for the purpose of immediate investigation. For early response system, when there is serious disease outbreak, aquatic animals in that epidemiological unit should be contained in safety area. Waste water also should not be released from that area without disinfection. Meanwhile, the DoF staffs should investigate the outbreak urgently in order to define disease zone and find out what factors associated with the outbreak so that the disease management or control measure can be applied properly.
    • Conference paper

      Way forward 

      MG Bondad-Reantaso - In EA Tendencia, LD de la Peña & JMV de la Cruz (Eds.), Aquatic Emergency Preparedness and Response Systems for Effective Management of Transboundary Disease Outbreaks … of Asean Regional Technical Consultation, 20-22 August 2018, Centara Grand Central Ladprao, Bangkok, Thailand, 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The overall objective of this technical consultation is to bring together the representatives of ASEAN Member States and technical experts to examine the status of aquatic emergency preparedness and response systems currently being practiced in the region in order to identify gaps and other initiatives for regional cooperation. In the general sense, the RTC is successful in achieving the general objective.

      As for the specific objectives, (a) to assess existing laws, legislations and standard operating procedures (SOPs), among others had been partially achieved. This is because the consultation didn t assess but was only informed (through the reports of country representatives) of the current situation in ASEAN member countries. The way forward of this is to complete the EPRS audit questionnaire as basis of the more systematic assessment. The second objective is (b) to assess the need for a regional aquatic EPRS in the ASEAN, the participant voted in the affirmative. The way forward of this is to create the ASEAN guidelines including the mechanics. The third objective is to (c) enhance cooperation among Member States, regional/international organizations and other relevant stakeholders on initiatives that support aquatic EPRS for effective management of aquatic animal disease outbreaks. This objective has been achieved. The way forward for this is to get the same people for a planned and proposed consultation II for continuity and for emphasis on more private sector and academe representation.
    • 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, 2019 - 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.
    • Article

      Improved survival, prey selectivity and diel feeding cycle of silver therapon Leiopotherapon plumbeus (Perciformes: Terapontidae) larvae reared in tanks with substrate 

      FA Aya, VSN Nillasca, MJP Sayco & LMB Garcia - Ichthyological Research, 2019 - Springer Verlag
      Physical substrates in the rearing environment can influence the early survival and feeding patterns of captive-reared fish. In this study, we determined whether substrates affect the survival and growth of hatchery-reared silver therapon Leiopotherapon plumbeus larvae as well as examined their prey selectivity and diel feeding cycle. Newly hatched larvae [1.92 mm total length (TL)] were reared for 40 days in triplicate 4 m3 tanks with or without tropical almond Terminalia catappa leaves as substrate. Prey selectivity of larvae reared in tanks with substrate for 35 days from the yolk-sac stage was measured by the Chesson’s selectivity index (αi). Diel feeding cycle of 3-4 days post-hatch (dph) silver therapon larvae reared in tanks exposed to natural light cycle and fed wild zooplankton was also studied. Larvae reared in tanks with substrate had significantly higher survivorship (48.44 ± 7.85%) than those reared in tanks without substrate (26.73 ± 1.60%). However, total length, specific growth rate and body weight of silver therapon larvae from tanks with or without substrate were not significantly different. Silver therapon larvae are generalist predator, demonstrating a degree of prey selectivity in some prey items during early ontogeny. Prey selectivity of silver therapon larvae varied during larval ontogeny, with higher Chesson’s selectivity index for copepod nauplii among the smaller fish larvae (2–5 dph; 2.94–5.17 mm TL), cladocerans (Moina micrura and Bosmina coregoni) among intermediate (6–11 dph; 5.72–9.60 mm TL), and ostracod, cladoceran and insect larvae among larger fish (12–35 dph; 10.28–20.96 mm TL). Larvae showed a diel feeding cycle where they actively fed during daylight hours, with a peak in the late afternoon, and reached a minimum at dark. Together, these findings advance our understanding of the feeding predatory behavior and efficiency of silver therapon larvae and preference for tanks with substrate that improve their survival.
    • Article

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

      DL Superio, SB Alayon & MGH Oliveros - Information Development, 2019 - 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

      Gonad development and size‐at‐maturity of silver therapon Leiopotherapon plumbeus (Kner 1864; Teleostei:Terapontidae) in tropical volcanic lakes in south Luzon, Philippines 

      PJT Denusta, EG de Jesus-Ayson, MA Laron, FA Aya & LMB Garcia - Journal of Applied Ichthyology, 2019 - Wiley
      Gonad development of the silver therapon Leiopotherapon plumbeus in two volcanic crater lake habitats (Sampaloc Lake, Taal Lake) in south Luzon, Philippines was examined during the annual reproductive cycle. The minimum body size‐at‐maturity of fish in these two lake habitats was also compared. Four gonad development stages were characterized as basis for the classification of ovarian (immature, maturing, mature, spawned) and testicular maturation (immature, maturing, mature) phases. The occurrence of all development stages in individual gonads suggest an asynchronous development whereby advanced stages are recruited continuously from a pool of younger stage germ cells to result in elevated female and male GSI throughout the annual cycle due to active gonadogenesis. Together with the increasing occurrence of advanced stage oocytes and spermatozoa from March until October, the elevated GSI of fish may indicate peak gonadal growth during the onset of the dry season (December–January) for eventual spawning from the beginning (May–June) until the end of the wet season (October–November). In both lake habitats, male fish were smaller than females but, regardless of sex, the minimum size‐at‐maturity of fish in Sampaloc Lake was significantly smaller than fish in Taal Lake. Overall, asynchronous development during oogenesis and spermatogenesis allows for year‐round reproduction of silver therapon, with elevated gonad growth in the dry season in preparation for spawning during the wet season. Compared with fish in Taal Lake, a smaller size‐at‐maturity of fish in Sampaloc Lake may be a response of the wild fishery stock to long‐term high fishing mortality and degradation of the lake habitat.
    • Article

      Female-specific SNP markers provide insights into a WZ/ZZ sex determination system for mud crabs Scylla paramamosain, S. tranquebarica and S. serrata with a rapid method for genetic sex identification 

      Mud crabs, Scylla spp., are commercially important large-size marine crustaceans in the Indo-West Pacific region. As females have the higher growth rate and economic value, the production of all female stocks is extremely essential in aquaculture. However, the sex determination mechanism is still unclear. Development of sex-specific genetic markers based on next-generation sequencing proved to be an effective tool for discovering sex determination system in various animals.
    • 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.
    • Newsletter

      AQD Matters 2018 May - June 

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