Southeast Asian Fisheries Development Center
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Establishment of threshold infection levels of WSSV in different weight ranges of Penaeus vannamei using quantitative PCR (qPCR)
Get PDFThreshold infection level is the pathogen load of the test animals measured before the appearance of clinical signs and mortality. This study aims to establish the threshold infection levels of WSSV in different weight ranges of Penaeus vannamei using qPCR. Artificial infection experiments were conducted using four weight ranges (3–5 g, 7–8 g, 15–18 g, and 22–25 g). The LD50 of the different weight ranges of shrimps were achieved at viral dilution of 10-6 and 10-5 after 216–240 hpi, and the viral loads of these inoculums have a range of 105–106 WSSV DNA copies/g. The viral loads of the samples in the timecourse infection experiments when the mortalities started was determined at 109 WSSV DNA copies/g, while for the survivors was at 106 WSSV DNA copies/g. The threshold infection level of WSSV in shrimp was determined at 107 to 108 WSSV DNA copies/g. It was also found out that the threshold infection level was not weight dependent.We are very grateful to the Government of Japan-Trust Fund (study code: FH-07- F2015T) and SEAFDEC/AQD for funding this work. We thank Mr. Ivan Yaptangco of IJY Shrimp Farm for providing the experimental animals and the staff of Fish Health Section Diagnostic Services for the technical support
Training updates on marine fish hatchery
Get PDFAbstract only.One of the major constraints confronting the sustainable development of the aquaculture industry in the world, particularly in Southeast Asia, is the availability of quality fish seeds for stocking in ponds and cages. With the unreliable supply from the wild, the establishment of fish hatcheries has long been recognized as a primary means of reducing pressure on wild stocks and plays a key role in supplying the demand for seedstock of fish farmers.
SEAFDEC/AQD has been conducting a short-term training course on marine fish hatchery since 1985, in response to the growing aquaculture industry and the increasing demand for information on seed production of culturally important and high-value marine fishes such as milkfish, sea bass, rabbitfish, groupers, red snapper, and pompano.
The training conducted last June 19–25, 2018 was attended by participants from Myanmar, Indonesia, Philippines, Tanzania, and Maldives.
This 37-days training course aims to equip the participants, working in the government, academe as well as in the private sectors, with technical knowledge through lectures and practicals on fish broodstock management, spawning, larval rearing, natural food culture, fish health management, nursery and grow-out culture, special topics on hatchery design, recirculating system, among others, of milkfish (Chanos chanos), sea bass (Lates calcarifer), groupers (Epinephelus coioides and E. fuscoguttatus), mangrove red snapper (Lutjanus argentimaculatus), rabbitfish (Siganus guttatus) and pompano (Trachinotus blochii). The participants conducted monitoring, culture, and scaling up of natural food organisms (green algae, Nannochlorum sp. and brown algae, Skeletonema tropicum; sampling of fish broodstock for induced spawning, and larval rearing.
The trainees successfully cultured, monitored the growth rate, and scaled-up the production of natural food organisms (green algae, Nannochlorum sp. and rotifer, Brachionus plicatilis) for fish larvae. At the end of each larval rearing runs, the trainees obtained the following percent survival rate: milkfish (12-33); snapper (7-13); rabbitfish (5-19); pompano (0.4-6); sea bass (26-40); and grouper (22-31). The trainees cited poor water quality in the larval rearing tanks, especially at the onset of the rainy season, as one of the main reasons for the low survival rates.
Maintenance of good water quality during larval rearing is an important factor for the efficient operation of a fish hatchery. To ensure a sustainable fish seed production and high survival rates, critical water quality parameters should be monitored and maintained within optimum levels at all times.
The trainees evaluated the conduct of the course and gave an overall rating of 4.46 (very good)
Field efficacy evaluation of a formalin-inactivated white spot syndrome virus (WSSV) vaccine for the preventive management of WSSV infection in shrimp grow-out ponds
No full textA shrimp grow-out trial was conducted in four 700 m2 earthen ponds in Dumangas Brackishwater Station of SEAFDEC Aquaculture Department, in Iloilo, Philippines to evaluate the efficacy of a combination of immersion- and orally-administered formalin inactivated vaccine (FIV) as an antiviral strategy against WSSV. Purified virus prepared by sucrose gradient ultracentrifugation was inactivated by overnight incubation in 0.5% buffered formalin. PCR-screened Penaeus monodon postlarvae (PL14) obtained from a commercial hatchery were divided into two groups: 1) immersed in FIV solution for 2 h before stocking in ponds (VAC); and 2) unexposed control (CON). Both groups were stocked at a density of 15 m−2 and grown for 115 d following recommended good practices. Pond water was aerated using two 20-HP electric blowers. Shrimp were given commercial feed following the manufacturer's protocol. They were booster-vaccinated by administering FIV-coated feed every 15 d until the termination of the trial. Shrimp samples were regularly collected to obtain estimates of growth, survival, and feed conversion ratio. In addition, shrimp and extraneous crustacean species were analyzed for the presence of WSSV and IHHNV by PCR. Water quality and bacterial load were monitored regularly. After 115 d of culture (DOC), shrimps grew to 12.93 ± 1.26 g in VAC and 8.54 ± 0.78 g in CON. Likewise, survival and yield was higher in VAC (71.2 ± 3.13% and 1311 ± 70.4 kg ha−1, respectively) compared to CON (52.7 ± 5.05% and 640 ± 3.0 kg ha−1, respectively). PCR analysis showed both shrimp and extraneous crustaceans to be lightly infected with WSSV and IHHNV. A few dead shrimp were noted during routine pond inspection as shrimp biomass increased towards the end of the trial. However, no mass mortalities occurred and shrimp were successfully harvested on 115 DOC. VAC and CON shrimp were also collected on day 70, 90, and 105 and experimentally infected with WSSV in tanks. Significant differences in survival rates (p < 0.05) between the groups were obtained 15 d post-challenge. Further studies in tanks and in ponds on prophylactic oral delivery of antiviral treatments with the use of protein vaccines and vectors/carriers are recommended.This work was fully supported by project funds from SEAFDEC/AQD and the Government of Japan Trust Fund under Study Code 8400-T-RD-FH0210. We wish to thank the management of the Dumangas Brackishwater Station (DBS) for use of the facilities during the field trial. The generous assistance of DBS and Fish Health Section staff are gratefully acknowledged
AQD Matters 2020 November - December
No full textIn this issue: 1) Iloilo mudworm likes it dark, study finds; 2) AQD's online presence grew during pandemic; 3) In-house training on effective presentation skills; 4) OPLAN BALIK SUGPO update
Oyster culture: Hatchery production of single spats slipper-shaped oyster Crassostrea iredalei
No full textThis manual intends to provide information on the techniques, processes, and recommend practices on hatchery production of single spats slipper-shaped oyster Crassostrea iredalei. This will serve as a guide for hatchery operators and shellfish farmers on the production and profitability of safe and quality single spats oyster for grow-out culture
Grey literature usage among Filipino aquaculture researchers: A bibliometric analysis of research from 2009 to 2018
No full textExtended abstract only.Aquaculture is one of the fastest growing food production industries globally (Natale et al., 2011), and it is expected to exceed the production of other animal production industries such as beef, pork, or poultry in the next decade (OECD and FAO, 2012). In the Philippines, aquaculture contributes significantly to food security, employment for the poor, women, youth, and foreign exchange earnings (FAO, 2019; Sekhar and Ortiz, 2006). The Philippines is the 11th top aquaculture producing country in the world; it ranked third, fifth, and ninth in seaweeds, finfish, and marine crustacean productions, respectively (FAO, 2018). However, unsustainable aquaculture practices in the country “contributed to nutrient loading, threatening environmental harm” (FAO, 2018). The majority of countries in the world, including the Philippines, are experiencing environmental problems due to unsustainable aquaculture practices. Thus, to address these problems and further develop aquaculture, research was actively done by the government, academic, and research institutions. According to Superio et al. (2019) research plays a major role in development, and commonly, the results were published for public consumption. However, some fisheries and aquaculture researches were unpublished and of limited distribution because a high proportion of fisheries information was published as grey literature (Parker et al., 2010). Notably, FAO (2009) found that fisheries information in developing countries was published in grey literature due to the stringent criteria of the editorial boards of Western peer-reviewed journals, while in Africa, an estimated 70 percent of fisheries information is published as grey literature
Distribution of the tropical seaweed crops Eucheuma spp. and Kappaphycus spp. inside and outside of their native range
No full textOral presentation presented at the 12th International Phycological Congress Puerto Montt, Chile 22–26 March 2021.Seaweed aquaculture is a fast-growing industry worldwide and has the potential to change the seascape of coastal regions, including the movement of species outside their native range. Two of the crops with the highest global production are the tropical red algal eucheumatoids, Kappaphycus spp. and Eucheuma denticulatum. Cultivation of these species has become an important source of income for coastal communities especially in many areas in South East Asia and the Western Indian Ocean. Low initial investment and a simple vegetative propagation through cutting fostered a rapid expansion of eucheumatoid cultivation and its introduction in diverse tropical and subtropical countries around the world. Despite the economic importance of eucheumatoid cultivation, its relevance for many coastal communities and its global expansion knowledge on genetic variation between and within cultivars of Eucheuma and Kappaphycus and their wild counterparts is yet limited. Through an international consortium we designed a global sampling campaign of cultivated and non-cultivated eucheumatoids from seaweed farms and natural habitats with focus on South East Asia (the Philippines, Malaysia and Indonesia) and the Western Indian Ocean (Tanzania and Madagascar), as well as specimens from non-native areas including islands in the Pacific (Hawaii, Kiribati, Fiji and Solomon Islands). In this talk, we will give an update of this ongoing project and outline initial results from a new initiative to determine diversity within cultivated eucheumatoid specimens from Tanzania. Our project aims at providing novel knowledge on the genetic resources of eucheumatoids in support of a sustainable seaweed industry
AQD Matters 2021 September - October
No full textIn this issue: 1) Trainees complete intensive aquaculture course; 2) First online sandfish training course a success; 3) SEAFDEC/AQD reviews achievements for 2021; 4) NFRDI and BFAR staff attend an online course on marine fish; 5) SEAFDEC lab now ISO accredite
Promotion of sustainable aquaculture in Malaysia
Get PDFAquaculture has been identified as a priority sector in the development of Malaysia’s economy. It receives a wide participation as a result of the progressive development in most parts of the country. From producing only about 7% of the national fish production in 1992, aquaculture has produced almost 13% to that of capture production in 2003, and expected to produce equal volume to the latter in the future. The aquaculture production leaped from less than 80,000 metric tonnes in 1992 to more than 427,000 metric tons in 2017 valued at MYR3 billion. Demand is expected to continue to grow with anticipated population growth. Aquaculture provides employment, business and investment opportunities in this country. As of 2017, there are over 18,000 aquafarmers in Malaysia, with a total farm size of more than 34,000 ha. Two key factors i.e. the physical and financial factors, have boosted the competitiveness of Malaysia’s aquaculture industry. The National Key Economics Area (NKEA) has become a mechanism to allow big players to lead private sectors participate in this industry. This paper intends to explicate Malaysia’s aquaculture potentials with a view to provide insight prospects for aquaculture growth