Southeast Asian Fisheries Development Center
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AQD Matters 2024 July - August
No full textIn this issue: 1) SEAFDEC expands aquaculture research complex; 2) AQD participates in USAID Southeast Asia Fisheries Partnership Workshop; 3) SEAFDEC/AQD connects with stakeholders at international exhibition; 4) SEAFDEC/AQD harvests vannamei shrimp; 5) Malaysian researchers train on marine fish hatchery, fish health management; 6) SEAFDEC/AQD conducts on-site training in Brunei Darussalam; 7) 51st Anniversary Celebration Highlights; 8) Nine graduate from the training course on marine fish hatchery; 9) Rehabilitated green sea turtle released in Antique waters; 10) Researcher presents study on the predator-induced behavior of hatchery-bred sandfish juveniles; 11) Seminars held for employee development; 12) SEAFDEC/AQD united through sports and teamwor
Promoting sustainable aquaculture of freshwater species: The continuous quest for alternative feeds and adoption of feeding strategies
No full textAmong farm inputs, feeds are the highest recurring cost in aquaculture. Indeed, feeds have become even more expensive after the COVID-19 pandemic, undeniably affecting the aquaculture economics. The pressing need to alleviate feed costs has to be prioritized, considering its implications for sustained aquaculture production to support the ever-increasing global population. Substantially, the rising costs of manufactured feeds have driven the continuous quest for new alternative feed ingredients in aquafeeds and the adoption of feed management strategies to improve the profitability of aquaculture operations. These two strategies addressed in this study are imperative in promoting freshwater aquaculture among the ASEAN Member States. This article highlights the exploration of feeding trials using alternative protein sources and feeding strategies. Because of their economic relevance to the freshwater aquaculture industry in the Philippines, Nile tilapia, giant freshwater prawn, and tropical anguillid eel, particularly the Pacific shortfin eel, were chosen in this study
Supplementation of commercial probiotic Lactobacillus casei in rearing early-stage silver therapon (Leiopotherapon plumbeus) larvae: Effects on growth, body composition and stress tolerance
No full textSupplementation of probiotics in live feeds and rearing water may improve the growth, survival, and resistance of fish larvae. This study examined the beneficial effect of a commercial probiotic bacteria Lactobacillus casei on the growth, body composition, and stress resistance in early-stage silver therapon (Leiopotherapon plumbeus) larvae. Larvae at 12 d post-hatch (DPH) (9.76 ± 1.32 mm total length [TL] and 13.48 ± 4.80 mg body weight [BW]) were reared in triplicate groups of 15 larvae per tank from 12 – 40 DPH (Phase 1) and 41 – 96 DPH (Phase 2). From 12 – 40 DPH, larvae were fed (I) unenriched Artemia nauplii (no-PB or control group); (II) probiotic-enriched Artemia nauplii (PB); and on (III) probiotic-enriched Artemia nauplii and rearing water (PB + W). The same feeding regime was used from 41 – 96 DPH except that the larvae were co-fed Artemia nauplii and microparticulate diet (MPD). Mean survival rates at 40 (97.78% – 100%) and 96 DPH (86.67% – 91.11%) did not show significant differences among treatments. However, except for body depth (BD) and Fulton’s condition factor (K), mean TL, BW, length increment (LI), and length- (SGRL) and weight-specific growth rates (SGRW) of PB + W-fed larvae were significantly higher than PB-fed and no-PB-fed larvae at 40 DPH. While these parameters were similar among treatment groups at 96 DPH, slightly higher values for BW and SGRW were noted for the PB + W group, as supported by the higher proportion of L. casei to total microbiota in the intestines of early-stage larvae. Whole body protein and lipid contents were highest in the PB + W and PB groups, respectively, but did not differ from the no-PB group. Survival rates (93.33% – 100%) after 18 h exposure to 30 ppt did not show significant differences. However, recovery rates after 15 min of air exposure of early juveniles in the PB and PB + W groups (93.33%) were significantly higher than those fed unenriched Artemia (66.67%). These results indicate that supplementation of probiotic bacteria L. casei in live feed and rearing water may support growth of early-stage larvae of silver therapon and its resistance to stress conditions during culture.Funding for this study was provided by the SEAFDEC Aquaculture Department (Br-02-F2015B). The authors thank R. Celebre and R. Lazartigue for the laboratory assistance
Bioremediation of oil spills: Current status, challenges, and future prospects
No full textThe petrochemicals produced from refining oil have become a large part of human life, making oil a valuable and expensive commodity. As a non-renewable resource, extraction and transport efforts have intensified to keep up with the demand, increasing the occurrences of oil spills. Such accidents have devastating impacts on the environment, the health of organisms, and a country's economy like the Philippines, and thus, need to be resolved immediately. One way to deal with oil spills is through bioremediation but the process is still facing several challenges. For one, the toolbox for bioremediation is limited. About 79 genera of bacteria were observed to degrade oil but there are only a small number of bacterial species and/or strains that have been recognized as useful for bioremediation. Second is that most oil-degrading bacteria found have low oil degradation efficiencies. Another challenge is keeping the bacteria alive to carry out the process. Fortunately, progress has been made in solving these challenges. Researchers are now testing different consortia, including bacteria–bacteria, bacteria–fungi, bacteria–microalgae, that can complement each other such as biosurfactant-producing bacteria with different oil-degrading microorganisms or microalgae or fungi that enhance the growth of oil-degrading bacteria. A consortium like this improves the survivability of each microorganism and enhances the oil-degrading efficiency. Moreover, the search for additional oil-degrading and biosurfactant-producing bacteria and other microorganisms to add to the bioremediation toolbox has been improved with the emergence of high-throughput sequencing. Aside from microorganisms, seaweeds have shown potential for bioremediation. The seaweed Caulerpa prolifera has been demonstrated to degrade diesel up to a certain concentration with the help of the bacteria growing on its surface. Bioremediation has a long way to go, but recent developments have shown promise and it remains to be the cheapest, most environment-friendly, and most effective way of dealing with oil spills
Achieving sustainable aquaculture in Southeast Asia: A case study on community-based giant freshwater prawn production in Laguna Lake, Philippines
No full textThe Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) implemented the project “Sustainable Aquaculture through Cost-effective Culture Systems, and Prompt and Effective Aquatic Animal Health Management” from 2020 to 2024 with support from the Japanese Trust Fund (JTF). The Project consists of three main activities: 1) cost-effective culture system, 2) prompt and effective aquatic animal health management, and 3) capacity enhancement for sustainable aquaculture. It complies with Resolution No. 16 Strengthen aquaculture governance and implement good aquaculture practices to sustain production for food safety and security, sustainable livelihoods, and rural development of the ASEAN-SEAFDEC Resolution and Plan of Action on Sustainable Fisheries for Food Security for the ASEAN Region Towards 2030 (RES&POA-2030).
Recognizing the success and expertise of AQD in the development of aquaculture technologies, especially in broodstock management, spawning, larval rearing, nursery and grow-out culture of aquatic fish, crustaceans, mollusks, sandfish, and seaweeds, feed development, fish health management, development of vaccine treatment, protective measures against existing and emerging diseases, community-based resource management, and implementation of aquaculture related training courses, the Project was conducted to improve the stability and sustainability of aquatic food production and for technology dissemination in the Southeast Asian region. Under Activity 1 of this Project, this study aims to establish a community-based seedlings supply system.
This article highlights the inherent challenges of hatchery production, particularly our growing vulnerability to climate variability, including temperature fluctuations and water quality issues. Effective data monitoring can guide adaptive management strategies through science-based strategies, such as investing in appropriate technologies, adjusting densities, and changing feeding practices to boost production yields
Morphological and genetic diversity assessment of freshwater prawns (Macrobrachium spp.) in the Cairawan river, Antique province, Panay island, Philippines
No full textFreshwater prawns of the genus Macrobrachium are among the most valuable cultured aquatic species in the world. The systematic study of Macrobrachium species in the Philippines has often been based on morphological trait assessment. Here, we combined morphology and molecular approaches to study the presence and actual distribution of Macrobrachium species along the Cairawan River in Laua-an, Antique Province, Panay Island. Using morphological characteristics, we identified 11 Macrobrachium species, the highest number of species reported from a single river. Molecular results based on the cytochrome oxidase subunit I (COI) mitochondrial DNA (mtDNA) sequences confirmed the morphological identification. The analysis revealed eight major clades with 19 distinct haplotypes within the species. Our results provide information on the identification of Macrobrachium species inhabiting the Cairawan River. The baseline information can be helpful for future genetic studies involving freshwater prawns with potential use in aquaculture. It can provide scientific data to facilitate the formulation of selective breeding plans and direct governance policies in freshwater prawn resource conservation and management in the Philippines
Sandfish (Holothuria scabra) as potential reservoir of white spot syndrome virus (WSSV) when co-cultured with black tiger prawn (Penaeus monodon)
No full textSince the first occurrence of White Spot Disease (WSD) in 1992, it is still listed as one of the crustacean diseases by the World Organisation for Animal Health in 2022. Horizontal transmission in co-culture systems is one of the usual modes in the spread of the disease. WSD outbreak was recorded during the experimental run of the co-culture of black tiger prawn (Penaeus monodon) and sandfish (Holothuria scabra) in the grow-out phase. In this study, artificial infection through two cohabitation experiments were conducted to determine if H. scabra is a potential non-crustacean vector or reservoir of WSSV. Samples were checked using one-step and nested PCR for increased readout sensitivity of virus infection to investigate the horizontal transmission between prawn and sandfish. During the first cohabitation (5 days) where WSSV (+) prawn were cohabited with WSSV (-) sandfish, 100% of the prawn were one-step PCR positive for WSSV while 100% of the sandfish were nested PCR positive. Subsequently, WSSV (+) sandfish from the first cohabitation were transferred to another tank to be cohabited with WSSV (-) prawn. Sampling of both prawn and sandfish was done every 6 days post-infection (dpi). At 6 to 18 dpi, prawn and sandfish were nested PCR positive. At 25 dpi, there were no prawns left due to mortality and 1 of the 3 remaining sandfish was nested PCR positive. Based on the results, it elucidates the ability of sandfish to bioaccumulate the viral particles when cohabited with WSSV (+) prawn. Results suggest that WSSV is viable in the sandfish confirming its potential as a vector or reservoir due to the consistent nested PCR positive results of the prawn during the second cohabitation. Hence, it can be inferred that sandfish can be a potential non-crustacean vector or reservoir of WSSV for a limited period of time.Special thanks to SEAFDEC/AQD and JIRCAS for the funding support (6195-T-RD-WATANA), the shrimp farm and sandfish hatchery for providing experimental animals, and the staff of the Fish Health Section for the assistance during the conduct of this study
