Southeast Asian Fisheries Development Center
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Growth performance and condition factor of juvenile milkfish (Chanos chanos) cultured in a marine pen in relation to body size and temperature
No full textThe growth performance and condition factor (CF) of milkfish (Chanos chanos) in relation to body size and temperature were investigated in a shallow marine pen culture system in coastal waters of the Philippines. Three common models were tested to determine the best-fit model for the growth of milkfish, and the logistic model was found to be best for both weight-based and length-based growth. Daily specific growth rate in weight ( and length ( were positively correlated with water temperature, while both and were correlated negatively with the size of the fish, which supported the fit of the growth model. CF of milkfish exhibited a positive correlation with the feed conversion ratio and significant seasonal variations. The ratio was lower in the fast growth season (dry season) than in the slow growth season (rainy season). By integrating these controversial findings, we were able to posit that low temperature and inefficient feeding makes ‘fat’ fish and vice versa. This may be explained by changes in proximate body composition (e.g., protein and water content) and the change in metabolic rate brought about by different water temperatures.This study was funded by the Japan International Research Center for Agricultural Sciences (JIRCAS) research project, “Development of Technologies for Sustainable Aquatic Production in Harmony with Tropical Ecosystems.
Genetic diversity, population structure and demographic history of the tropical eel Anguilla bicolor pacifica in Southeast Asia using mitochondrial DNA control region sequences
No full textThe following is the supplementary data to this article: Appendix A. Supplementary dataThe tropical catadromous eel, Anguilla bicolor pacifica, an important fishery resource in Southeast Asia, is under threat due to overexploitation (especially of its glass eel phase) and the limited information on their current genetic status which is necessary for resource management. Mitochondrial DNA (mtDNA) control region sequences, a useful marker for population genetic studies in many aquatic organisms, were used to investigate the genetic diversity, population structure and demographic history of A. bicolor pacifica in the region. A total of 151 specimens were collected from three sites in Southeast Asia, namely: Phu Yen, Vietnam (n = 48); General Santos, Philippines (n = 52); and, Palu, Indonesia (n = 51). A total of 138 haplotypes were identified using the mtDNA control region sequences. In spite of the lack of shared haplotypes, low and non-significant values, high haplotype diversity in concurrence with relatively low nucleotide diversity, a haplotype network with no phylogeographic structuring indicate no significant genetic population structuring among the eel samples from Vietnam, Philippines and Indonesia. Population expansion of A. bicolor pacifica was also suggested based on the results of the neutrality tests, mismatch distribution analysis and Bayesian skyline plot. Taken together, a joint management strategy for A. bicolor pacifica must involve countries in Southeast Asia particularly Vietnam, Philippines and Indonesia for its sustainable use.This research received financial support from the Japan ASEAN Integration Fund Project entitled “Enhancing Sustainable Utilization and Management Scheme of Tropical Anguillid Eel Resources”
Vibrio harveyi-like bacteria associated with fin rot in farmed milkfish Chanos chanos (Forsskal) fingerlings in the Philippines
No full textMilkfish (Chanos chanos) is a commercially important species widely cultured and consumed in the Philippines. It is a hardy fish but due to culture intensification, occurrence of bacterial disease is inevitable. The causative agent of fin rot disease in milkfish fingerlings (total length [TL] = 2.8–4.5 cm) reared in intensive nursery earthen ponds in the Philippines was investigated in the current study. Following biochemical characterization tests and 16S rRNA sequencing, seven isolates recovered from affected fish were identified as Vibrio harveyi-like bacteria. Immersion challenge of milkfish (TL = 5.64 ± 0.76 cm) using a representative strain (CCL-01) at inoculum dose of 108 CFU/mL resulted in fin rot as early as 1-day post-infection (dpi) and concomitant mortalities of 57% ± 0.58 at 7 dpi. Moreover, when milkfish (TL = 6.18 ± 0.66 cm) stocked at 5, 10, and 20 fish/5 L were exposed to the computed 168-h lethal dose (LD50) at 6.63 × 104 CFU/mL, significant mean mortality of 45% ± 1.0 coupled with typical signs of fin rot were particularly obtained in fish stocked at 20 fish/5 L (biomass = 4 g/L) while low mortality of 0% and 7% ± 0.58 were recorded in fish stocked at 5 fish/5 L and 10 fish/5 L, respectively, at 7 dpi. Vibrio harveyi-like bacteria was reisolated in lesions and kidney of all challenged fish while none in any of the control fish. The current data clearly indicate that the isolated V. harveyi-like bacteria is an opportunistic pathogen capable of instigating disease epizootics in milkfish fingerlings stocked at higher densities.This study was funded by the Department of Science and Technology through the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) under the UPV-DOST Milkfish Program A. Also, Oversea Feeds Corporation, SEAFDEC Aquaculture Department and Dr. Carlo Lazado are greatly acknowledged for the milkfish samples, use of the research facilities and valuable inputs in editing an earlier draft of the paper, respectively
Production, feeding and storage of diatom Chaetoceros calcitrans paste by electrolytic flocculation with reduced Pb content
No full textAn innovative microalgae harvesting technique was carried out under various anode/cathode (2/2, 4/4 and 6/6) configuration and at different voltage treatment (3, 6 and 10 V) to efficiently electroflocculate Chaetoceros calcitrans. This study was conducted to determine the optimal configuration of electrode units (Pb and Al) and voltage settings that could improve the quality of harvested paste in terms of nutritional value and metal contamination for its later use in aquaculture. The use of 6/6 electrodes achieved the shortest harvest time of 48 ± 1 min and the lowest Pb content (83.7 ± 0.3 ppm). In terms of voltage treatment, harvest time was inversely proportional to the voltage used. However, Pb content was significantly lowest in the paste produced using 3 V (41.78 ± 0.12 ppm), when compared to those harvested under 6 V (304.35 ± 0.79 ppm) and 10 V (343.90 ± 0.91 ppm) treatment. Likewise, Pb residues in the resulting effluent are also lowest (0.245 ± 0 ppm) with 3 V treatments. C. calcitrans paste can be resuspended ≤6 months but with a lag phase of 3–4 days for use as starter culture. A 97% reduction in Pb content of C. calcitrans paste and 77% reduction in Pb content were obtained in Artemia (7.8%) fed C. calcitrans paste.This project was funded by the Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD) with Study Code Nr-01-Y2018T
Biodiversity in mangrove-derived aquaculture ponds in Dumangas, Iloilo, Philippines
No full textLarge tracts of mangroves have been converted into aquaculture ponds and the consequent loss of biodiversity has been much decried. This paper shows that high aquatic biodiversity is retained in mangrove-derived aquaculture ponds in Dumangas, Iloilo, Philippines. Documentation of biodiversity was carried out over two years in 15 adjacent ponds (water areas 0.25–0.9 ha) used for farming penaeid shrimps, mud crabs, milkfish, seabass, rabbitfish, and other fishes. At harvest, these ponds yielded many extraneous non-crop or “bycatch” species, which had been naturally seeded by the tides and had grown (and some species reproduced) over the 2–10 mo that the ponds were underwater. From 21 crop cycles were obtained 8–56 species (from 6–30 taxonomic families) of bycatch fishes and macrocrustaceans with biomass of 2.5–168.4 kg ha–1 and abundance of 2–92 x 103 individuals ha–1, the differences due to pond area, duration of immersion, farming system, crop species, and the bycatch community. Some 85 species (44 families) of fishes occurred in the ponds, including 12 species of gobies, of which the small-size Acentrogobius viganensis, Pseudogobius javanicus, Mugilogobius cavifrons, and Gobiopterus panayensis reached high abundance. Macrocrustaceans consisted of 30 species (nine families), including several penaeid and palaemonid shrimps (Metapenaeus ensis and Nematopalaemon tenuipes were most common) and portunid and grapsid crabs. Mollusks in the ponds included 58 species (24 families), of which Cerithideopsilla cingulata was most abundant. The Dumangas ponds were leaky and allowed tidal recruitment of many mangrove animals despite net screens and chemical treatments. Existing tidal ponds serve as proxy mangrove lagoons (wetlands) that can harbor high aquatic biodiversity.The SEAFDEC Aquaculture Department funded this study
The Philippines recommends for mangrove crab
No full textForewordAcknowledgmentThe Mangrove Crab Technical CommitteeGlossary of TermsList of Abbreviations and AcronymsIntroductionCommodity ProfileBiology of Mangrove Crab Parts of a Crab Identification of Crab Species Life CycleFood and FeedingMoltingMatingSpawiningEmbryonic and Larval Development Hatchery Operation Site Selection Layout of HatcheryTanksTank PreparationWater Disinfection Culture of Natural FoodCulture of Marine Algae (Nanochlorum or Nannochloropsis)Culture of Rotifers (Brachionus)Hatching and Culture of Brine Shrimp (Artemia) Management of BroodstockSelection and TransportAcclimation and DisinfectionFeedingWater ManagementSpawning Larval RearingStocking of ZoeaeFeeding ManagementWater ManagementTransfer of Megalopae or Crab InstarHealth Management Cost and Return AnalysisCulture of Crablets Site Selection Pond Layout and Construction Pond Preparation Nursery PhaseFacilitiesStocking and MonitoringFeeding ManagementWater Management and Harvesting Cost and Return AnalysisGrow-out Phase PondStockingFeeding ManagementWater ManagementMonitoring and SamplingHarvesting PensConstruction of PenStockingFeeding and Water ManagementMonitoring and SamplingPredatorsHarvesting CagesConstruction of CagesStockingFeeding ManagementMonitoring and MaintenanceHarvesting Health Management Cost and Return AnalysisSoft-Shell Crab Production Site Setup Crab Boxes in Pond Roofed Bridge and Floating Platforms Culture of Mangrove CrabsSourceStocking of CrabsFeeding and Water Management Cost and Return Analysis Market Outlet Philippine National StandardsPostharvest and Transport Postharvest Postharvest Quality of Crabs Packing Transport Holding Facilities Hygiene and Sanitation PracticesMarketing Market Forms Market Outlet and Supply Chain Export Market Access Requirements Philippine National Standards Genetics Genetic Marker Associated Technologies for ImprovedMangrove Crab Breeding and Farming Morphometric and Genetic Approaches in Mangrove Crab Species/Stock Identification Genetic Considerations in the Development and Management of Mangrove Crab Broodstock Mapping Ideal Sites and Identifying Heat Stress Resilient Stocks Determining Optimal Temperature-salinity Conditions for Mangrove Crab Farming ReferencesAnnex A. Mangrove crab holding facilities registered under BFAR-NCR in 2018Annex B. Philippine exporters of mangrove crabs; BFAR, July 2018</ul
Preliminary survey of pests and diseases of eucheumatoid seaweed farms in the Philippines
No full textFarmed eucheumatoids are the top aquaculture commodity in the Philippines, contributing more than 60% of total national aquaculture production by volume. Despite significant production losses observed in recent years due to pests and diseases, data relating to the temporal and spatial geographic distribution, seasonality, prevalence, and etiology of these critical problems at the farm level are lacking. Here, we assessed the prevalence of pests and diseases at 16 farm sites within several major seaweed growing areas, including Luzon (Palawan), Visayas (Bohol), and Mindanao (Zamboanga City, Davao del Norte, and Tawi-Tawi). Prevalence of pests and diseases were recorded by assessment of individual seaweed plants in situ, comprising ≥5% of the total number of seaweed plants on each farm. Results from this survey revealed “ice-ice” disease (IID) at all sites, albeit at low prevalence rates of below 25%, the exception being one site where prevalence was 100%. No significant difference in the prevalence of IID was found between farms in shallow (≈0.5 m during low tide) and deep water sites (depths exceeding 4 m during the lowest tide) (p>0.05). Moderate prevalence (26–50%) of the macro-epiphyte pests Sargassum and Ulva was reported in Luzon. Further, epiphytic filamentous algae (EFA), black spots, and evidence of grazing were recorded in several farms with low prevalence (0.2–11.2%). The three farms with the highest prevalence of IID and EFA were evaluated to determine the severity of cover on the thallus of infected plants. A very high severity of IID (76–100% coverage) was observed on the secondary and primary branches, while for EFA, low severity (≤25%) was found in all regions of the thallus. Our results suggest the widespread occurrence of yield-limiting diseases and pests affecting eucheumatoid farms in the Philippines. Strategies for the diagnosis, surveillance, and management of yield-limiting pests and diseases are needed to ensure maintenance and sustainable expansion of this important aquaculture sector in the Philippines.This study was mainly supported by the United Kingdom Research and Innovation–Global Challenges Research Fund (UKRI-GCRF) “GlobalSeaweedSTAR” Programme (Grant No. BB/P027806/1) and implemented in part at SEAFDEC/ AQD with a Study Code: FH-01-S2017T
Aquaculture seeds and feeds at the core of AQD’s collaboration with the government of the Philippines
No full textFor almost 50 years, SEAFDEC/AQD has been generating scientific information behind aquaculture technologies applied in Southeast Asia and other parts of the world. Since 2017, AQD and its host country, Philippines, have upgraded their collaborative programs to accelerate the implementation of projects that address the needs of the local aquaculture industry. A reliable supply of quality seeds and a source of cost-efficient nutrition are at the core of the partnership, these being the most pressing issues faced by fish farmers. In just four years, AQD had made significant headways in providing technical support to the government agencies of Philippines