Southeast Asian Fisheries Development Center
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Burning grey: The worldwide influence of a locally published grey literature
No full textRice is a major staple crop in the Philippines, which produces a large amount of rice each year. On the other hand, rice production generates biomass waste in the form of rice husks. In consideration of the rice husks’ potential as a biomass energy source and support the development of the rice husk gas stove technology in the Philippines, Engineer Alexis T. Belonio had published a grey literature (GL) entitled “Rice Husk Gas Stove Handbook.” Hence, to fully understand the impact of the technology, a citation analysis was conducted. The works that cited the GL were retrieved from Google Scholar using Harzing’s Publish or Perish software. The complete title of the GL was used as keywords for the search string. Results revealed that the GL was cited by 155 literatures written by 398 authors from 31 countries. Seventy-five (48.4%) of the 155 literatures were cited 797 times. The results showed the wide utilization and the impact of locally-published GL, thereby confirming GL’s value in research and development
AQD Matters 2022 January - February
No full textIn this issue: 1) Iloilo City gov’t seeks assistance from SEAFDEC/AQD; 2) Oyster spat deployed to ponds for rearing; 3) Japan-funded programs reviewed; 4) Cost-efficient feeds reap rich pompano harvest; 5) Let's talk about mouthbrooding; 6) Employees, dependents get booster shot vs COVID-1
Ice-Ice disease: An environmentally and microbiologically driven syndrome in tropical seaweed aquaculture
No full textSeaweeds account for nearly 30% of global aquaculture production by volume, and their cultivation provides important opportunities for employment and wealth generation, particularly in rural coastal communities. Eucheumatoids (Kappaphycus and Eucheuma spp.) are tropical red algae commercially cultivated as raw material for production of carrageenans, particularly in South-East Asia and the Western Indian Ocean region. Diseases and pests are major limiting factors in eucheumatoid production, particularly a condition known as ‘ice-ice’ disease (IID). IID is characterized by bleaching of the thallus followed by the disintegration of affected tissues, leading to a loss of biomass and reduced carrageenan yield. IID has been associated with unfavourable changes in environmental conditions, particularly an increase in sea water temperature and a decrease in salinity, and infection by opportunistic or pathogenic bacteria. However, given that no single or combined causal agents have been definitely identified, IID may be considered a complex pathobiotic syndrome in which multiple factors contribute to the development of disease signs. Here, we review current knowledge of the abiotic and biotic factors associated with the development of IID, and the strategies employed to mitigate economic losses resulting from disease outbreaks. We discuss syndromic diseases in other marine holobionts, particularly other red algae and corals, in relation to their similarity to IID, and suggest the application of comprehensive and complementary methodologies, including high-throughput sequencing and high-quality microscopy, for enhancing our understanding of the pathological and microbiological processes associated with IID signs.All authors were supported by funding from UKRI for the GlobalSeaweedSTAR project (BB/P027806/1)
Intracellular production of recombinant GnRH1 in yeast, Pichia pastoris, and its potential as oral treatment to advance gonadal development in juvenile orange-spotted grouper, Epinephelus coioides
No full textLate maturation and large size at maturity are significant challenges when administering hormonal treatments in captive broodstock. Here, we report the potential of yeast, Pichia pastoris, as a vehicle to orally deliver a recombinant gonadotropin-releasing hormone (rGnRH1) aimed at stimulating gonadal development in juvenile orange-spotted grouper, Epinephelus coioides. Two recombinant GnRH1 constructs were designed utilizing pPIC3.5, the yeast expression vector lacking a signal sequence, hence retaining the recombinant within the yeast. The first construct (rGnRH1_1xGAP) comprised of GnRH1 decapeptide and the GnRH-associated peptide (GAP) separated by a cleavage site. The second construct (rGnRH1_10x) consisted of ten GnRH1 decapeptides, each separated by a cleavage site. Expression of the two recombinant peptides was confirmed by mass spectrometry. ELISA for the GnRH analogue (GnRHa) was validated to determine the level of rGnRH1 from the yeast extracts. Parallelism between the serially diluted GnRHa and serially diluted extracts from recombinant yeast confirmed validity of the assay. A luciferase reporter assay showed stimulation of tilapia GnRH type 3 receptor by the yeast extract, suggesting biological activity in vitro. In a short term experiment, lyophilised yeast loaded in gelatine capsules and fed once to juvenile orange-spotted grouper resulted in a significantly higher plasma GnRH compared with the control. In a 4-week experiment, lyophilized yeast containing either rGnRH1_1xGAP or rGnRH1_10x was incorporated in fish pellets and fed daily at a dose of 1 μg rGnRH1/kg fish body weight/day. The mean gonadosomatic index and oocyte diameter did not vary between the treated and control fish. The mean plasma levels of FSH, LH and GnRH in the rGnRH1-fed and control fish did not also vary significantly, however there were individuals in the rGnRH1-fed groups that had increased level of the hormones. Together with histological evidence showing oocyte development in a proportion of fish fed with the recombinant, results of the present study point to a biological activity in vivo of the rGnRH1 in yeast. With further refinement, this technology has the potential to provide a non-invasive method for broodstock management of large, late-maturing species of fish and of small, delicate endangered species that require breeding in captivity.This project was funded by grants to AE from the Australian Seafood CRC (No. 2008-745: The advancement of reproductive development in Southern bluefin tuna using hormonal manipulations of kisspeptin, the gatekeeper of puberty) and from the Australian Centre for International Agricultural Research (ACIAR FIS_2012_101: Developing technologies for giant grouper, Epinephelus lanceolatus, aquaculture in Vietnam, the Philippines and Australia). This study was also partly funded by SEAFDEC/AQD (Study Codes: TV-01-F2020T, Br-03-F2018T). PP was supported by a John Allwright Fellowship from ACIAR
Seasonal growth, organ indices and food consumption of the Japanese scallop Patinopecten yessoensis (Jay, 1857) in relation to food availability in Tokoro seabed, Okhotsk Sea, North Japan
No full textThe coastal waters off Tokoro, Okhotsk Sea have been characterized by a substantial decrease in primary production from spring to summer season which will have repercussions on the maintenance of the Japanese scallop Patinopecten yessoensis (Jay, 1857) culture. This study examined the seasonal changes in scallop growth, condition and organ indices in relation to environmental conditions, and compared the sinking particulate organic carbon (POC) flux as an estimate of food availability to scallop food requirements. Monthly specimens were obtained in July 2005, and from May 2006 to December 2008 off Tokoro, Okhotsk Sea. Growth parameters derived from the modified von Bertalanffy growth function of 885 scallop individuals were the mean asymptotic shell height H∞=126.51 mm, Brody growth coefficient K=0.081 year−1, and t0=6.19 year. Condition (CI) and gonadosomatic indices (GSI) increased in April and May, decreased from June to September, but increased again from October until May. The adductor muscle index (AMI) increased from June to October, but declined from November until May when CI and GSI began to increase. Primary production (PP) and chlorophyll a biomass decreased from spring (25.75–29.74 µg C L−1 h−1 and 1.74–5.37 µg L−1) to autumn (0.90–10.83 µg C L−1 h−1 and 0.29–0.75 µg L−1) concurrent with decreasing CI and GSI, but no deleterious effect on AMI was evident during these periods. The sinking POC flux (25–68 mg C m−2 day−1) was low during summer when gonad activity was also low, but started to increase in autumn when gonad activity started to peak. Although a deficit in food availability (lower sinking POC fluxes than scallop food consumption) was observed during summer, the potential advection of organic matter from offshore to nearshore region may have provided additional source of food to bottom-cultured scallops, contributing in part to the increase in shell growth and somatic tissues
Research breakthrough seen to curb shortage of 'poor man's fish'
No full textA scientific breakthrough at a research center in the Philippines might finally be the long-term solution to the perennial shortage of round scad (Decapterus spp.), known as the “poor man’s fish” in the country.
In a world’s first, researchers successfully spawned the round scad Decapterus macrosoma in captivity at the Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC/AQD) in Tigbauan, Iloilo, marking a critical milestone towards farming the fish, locally known as galunggong
Acute lethal toxicity of dried garlic (Allium sativum) powder on orange-spotted grouper (Epinephelus coioides) juveniles under static exposure
No full textThe present study was carried out to assess the toxic effect and determine the lethal concentration of dried garlic (Allium sativum) powder on the orange-spotted grouper (Epinephelus coioides) juveniles. Laboratory static bioassays were conducted to determine the 96-h LC50 of different concentrations of garlic (0, 30, 60, 90, 120, 150 and 180 mg L-1) on grouper juveniles (mean weight, 35.4±6.18 g and mean length, 13.2±0.51 cm). The 96-h LC50 was 74.78 mg L-1 with lower and upper confidence limits of 62.8 and 89.06 mg L-1, respectively. All fish exposed to 30 to 180 mg L-1 exhibited rapid movement, faster opercular activity and erratic swimming whereas at higher concentrations (90 mg L-1 to 180 mg L-1) fish showed additional behavioral changes such as loss of balance, lethargy, gulping for air and respiratory distress. Water quality parameters were within the recommended acceptable limits. This LC50 value can be used as a baseline reference to generate an effective concentration of garlic for future prophylaxis and treatment for parasitic, viral and bacterial infection in grouper.The authors are grateful to the Government of Japan Trust Fund GoJ-TF6 (8400-T-RD-FH0215) for supporting and funding this research. In addition, the authors extend their thanks to Mr. Peter Palma for his time in carefully reviewing our manuscript. Thanks are due to Mr. Elvis Biñas for his technical assistance
Microbiological quality and heavy metal concentrations in slipper oyster (Crassostrea iredalei) cultured in major growing areas in Capiz Province, Western Visayas, Philippines: Compliance with international shellfish safety and sanitation standards
No full textThe increasing demand for slipper oyster (Crassostrea iredalei) has propelled farmers to expand oyster cultivation areas in the Philippines, chiefly for local consumption and feasibly for export overseas. As filter feeders, oysters can accumulate pathogens from the surrounding waters, and these pathogens can cause foodborne diseases in consumers. Therefore, oyster farming areas must be monitored for microbiological quality and heavy metal concentrations. In the present study, the microbiological quality of oysters and their growing waters in the major oyster farming areas of the Cogon and Palina Rivers and Cabugao Bay (in Roxas City and the Municipality of Ivisan, respectively, Capiz Province, Western Visayas, Philippines) were examined monthly during the wet (May to October) and dry (November to April) seasons over 12 months. Regardless of the sampling period, high levels of fecal coliforms in the water and Escherichia coli in oysters were found, clearly illustrating that these oyster growing areas would meet only the class B standard under the European Union classification system and would be considered “prohibited” for growing oysters under the U.S. classification system. Although Salmonella was occasionally detected in oysters, Vibrio cholerae was not detected and Vibrio parahaemolyticus was within acceptable limits. The heavy metal concentrations in oyster meat were also determined during the wet (July) and dry (March) seasons. Zinc and copper were the most abundant metals detected, and concentrations of lead, cadmium, mercury, and chromium were below the regulatory limits set by the European Union and the U.S. Food and Drug Administration. These oyster culture areas should be rehabilitated immediately to improve the microbiological quality of the oysters. Oysters harvested from these sites must be depurated or relayed to ensure quality and safety.We express our heartfelt gratitude to Southeast Asian Fisheries Development Center/Aquaculture Department, Bureau of Fisheries and Aquatic Resources—Region VI, Negros Prawn Producers Cooperative, the local government units of the Municipality of Ivisan and Roxas City, and collaborators from Palina Greenbelt Ecopark, Barangay Cabugao, and Barangay Cogon. This study was funded by the Department of Science and Technology, Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (study code 6286-T-RD-DOST03)
Residence time models and Pyrodinium blooms in Matarinao and Murcielagos Bays, Philippines
No full textThis is the first report on hydrodynamic models to determine current and water residence time patterns for Matarinao and Murcielagos bays in the Philippines, which have a long history of harmful algal blooms (HABs). Field surveys were conducted in Matarinao Bay in April and August 2010 and in Murcielagos Bay in February 2011. Hydrodynamic models of the bays were developed, and spatially explicit water residence times were estimated from the models based on rates of concentration decrease of a tracer within the bay. Both bays exhibited two distinct areas – the mouth with faster current flow and low residence time, and the head area with slower current flow and higher residence time. During the southwest monsoon, the residence time at Matarinao Bay was 5 d longer than that during the northeast monsoon. Phytoplankton sampling in both bays confirmed blooms of Pyrodinium bahamense, but the spatial distribution did not consistently correlate with the simulated residence time patterns. While residence time plays a significant role in algal blooms, extraneous factors may also influence the distribution of phytoplankton within embayments
Understanding current challenges and future prospects in Integrated Multi-trophic Aquaculture (IMTA) research. Proceedings of the JIRCAS-SEAFDEC/AQD Joint Workshop on IMTA research held at SEAFDEC/AQD, Tigbauan Main Station, Iloilo, Philippines on 6-8 August 2019
No full textThis proceeding is a compilation of the 10-year achievements in IMTA research conducted by JIRCAS and SEAFDEC/AQD researchers and their collaborators, covering topics such as ecological characterization of target species, evaluation of environmental impacts, and socio-economic analysis