SEAFDEC/AQD highlights 2021

SEAFDEC/AQD highlights 2021 is SEAFDEC/AQD's annual report updating on its accomplishments and progress for the year 2021

AQD Matters 2023 March - April

In this issue: 1) SEAFDEC/AQD kicks off 50th anniversary celebration; 2) Oil spill-affected fisher folks learn freshwater aquaculture; 3) 4 fisheries grad join SEAFDEC's pool of skilled aquaculturists; 4) SEAFDEC/AQD stocks up on kawakawa, galunggong anew; 5) Neg Occ seeks assistance from SEAFDEC to establish multi-species hatchery; 6) Community-based hatchery to boost production of giant 'ulang

Aquaculture governance: Five engagement arenas for sustainability transformation

Supplementary materialA greater focus on governance is needed to facilitate effective and substantive progress toward sustainability transformations in the aquaculture sector. Concerted governance efforts can help move the sector beyond fragmented technical questions associated with intensification and expansion, social and environmental impacts, and toward system-based approaches that address interconnected sustainability issues. Through a review and expert-elicitation process, we identify five engagement arenas to advance a governance agenda for aquaculture sustainability transformation: (1) setting sustainability transformation goals, (2) cross-sectoral linkages, (3) land–water–sea connectivity, (4) knowledge and innovation, and (5) value chains. We then outline the roles different actors and modes of governance can play in fostering sustainability transformations, and discuss action items for researchers, practitioners, and policymakers to operationalize activities within their engagement arenas

Reproduction, early development, and larval rearing of the climbing perch Anabas testudineus (Teleostei: Anabantidae) in captivity

Induced spawning, early development, and larval rearing of the climbing perch Anabas testudineus were examined under captive conditions. Five female climbing perch [125.33 ± 3.27 mm standard length (SL); 70.67 ± 5.59 g body weight (BW)] were each paired with apparently mature males (108.50 ± 3.97 mm SL; 39.27 ± 4.70 g BW) and induced to spawn with 5,000 IU human chorionic gonadotropin (hCG) + 0.5 mL Ovaprim/kg BW. All hCG + Ovaprim-injected fish spawned 9 – 11 h after hormone administration but saline-injected fish (control group) failed to spawn. Mean egg production per female, fertilization and hatching rates, and larval production per female were 7,667 ± 1,313, 98.11 ± 1.63%, 61.01 ± 19.92%, and 4,435 ± 1,041, respectively. Fertilized eggs (1.52 – 1.96 mm in diameter) were almost spherical, non-adhesive, transparent, and buoyant due to a large, single oil globule (515 ± 33 µm in diameter). First cleavage appeared 30 min post-fertilization (MPF) and egg development lasted for 20 – 24 h post-fertilization (HPF) (29°C). Newly hatched climbing perch larvae [1.73 ± 0.08 mm in total length (TL)] with yolk volume (YV) and oil globule volume (OGV) of 0.545 ± 0.104 mm3 and 0.072 ± 0.013 mm3, respectively had no pigmented eyes or functional mouth parts and digestive tract, and immobile with the yolk sac pointed upward. Eyes became pigmented and both mouth and anus opened in 1 d old larvae (2.09 ± 0.04 mm TL) in preparation for exogenous feeding. Except for body depth (BD) and pre-anal length (PAL), a general increase in TL (1.73 – 3.72 mm), eye diameter (ED) (0.164 – 0.378 mm), head length (HL) (0.205 – 0.923 mm), and mouth gape (MG) size (0.308 – 0.552 mm) was observed, coinciding with yolk resorption in 7 d post-hatched larvae. Climbing perch larvae were reared at four stocking densities (25, 50, 75, 100 larvae L-1) and fed solely on live food (Brachionus rotundiformis from days 2 to 12 and Artemia nauplii from days 13 to 40) or co-fed live food and microparticulate diet (MPD) (Artemia nauplii from days 2 to 15 and Artemia + MPD from days 16 to 40). Mean survival rates at lower densities (25 – 50 larvae L-1) were significantly higher than those reared at 75 and 100 larvae L-1 (P < 0.05). Furthermore, climbing perch larvae co-fed Artemia nauplii and MPD showed better survival (28.67 – 81.00%) than those fed solely on live food (24.88 – 64.00%). However, at the end of the 40 d trial period, growth parameters did not vary significantly among densities (P > 0.05), except for the condition factor in larvae co-fed Artemia nauplii and MPD. Taken together, results demonstrate the effectiveness of hCG + Ovaprim for captive breeding and observations on the early development of climbing perch, and the feasibility of rearing the larvae at 25 – 50 L-1 on a combination of Artemia nauplii and MPD under laboratory conditions.This study was supported by the SEAFDEC/AQD (Nr-02-F2013B and Br-02-F2015B)

Black tiger shrimp (Penaeus monodon) hatchery operations using enhanced biosecurity measures

This manual, titled “Black Tiger Shrimp (Penaeus monodon) Hatchery Operations Using Enhanced Biosecurity Measures,” includes modifications on shrimp hatchery operations done by the Aquaculture Department of the Southeast Asian Fisheries Development Center to provide high- quality postlarvae for shrimp farming. Discussed also in this manual are the necessary protocols and biosecurity measures that shrimp hatchery operators can use as their guide. Main sections included in this manual: 1. Site Selection, 2. Biology, 3. Hatchery Layout, 4. Facilities and Equipment, 5. Biosecurity Standard Operating Procedures, 6. Hatchery Operations, 7. Diseases of Shrimps, and 8. Economic Analysis

Grow-out culture of oyster Magallana bilineata (Röding, 1798) using pouches: A comparison of growth and survival in the river and earthen pond

Oysters are among the most in-demand aquaculture commodities in the Philippines and worldwide. With the decreasing culture area and the deteriorating water quality of oyster beds, there is a need to explore new culture sites and techniques to address the problems of dwindling stocks and the increasing demand for better quality oysters. This study compared the growth and survival of the oysters Magallana bilineata, the new accepted name of Crassostrea iredalei, cultured in an earthen pond and the river using pouches suspended from rafts. Mean growth rates of oysters in length and weight were significantly higher in those reared in the river (0.56 ± 0.02 cm mo-1; 10.27 ± 0.42 g mo-1) than those in the pond (0.41 ± 0.03 cm mo-1; 5.99 ± 0.22 g mo-1), but the meat yield of oysters reared in the river (25.96 ± 0.92%) was almost the same as in the pond (24.05 ± 1.41%). Likewise, the proximate composition was the same for oysters coming from the river and the pond, respectively — 58.04 ± 0.14% and 53.86 ± 0.38% crude protein, 7.00 ± 0.08% and 7.93 ± 0.38% crude fat, 24.68 ± 0.07% and 28.54 ± 0.74% nitrogen-free extract, and 10.27 ± 0.01% and 9.68 ± 0.01% ash. Oyster survival at harvest was significantly higher in the river (70.21 ± 2.84%) than in the pond (13.10 ± 1.57%). However, with some interventions, ponds may still be utilized for oyster culture despite the low survival results in this study. Extending oyster culture in these aquaculture facilities may serve as a basis for interventions to make the pond more habitable for oysters and may help boost production in the country.The authors greatly appreciate the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) for funding the study (Project Code FS-02-M2019T)

Bacterial diseases of tilapia, their zoonotic potential and risk of antimicrobial resistance

Tilapia culture is an important source of income and nutrition to many rural families. Since 2000, the production of tilapia increased and reached domestic and global markets. Major farmed species is Nile tilapia (Oreochromis niloticus), in earthen ponds and cage cultures. Intensification contributed to global tilapia disease outbreaks, with bacterial infections causing mortalities and morbidities, threatening sustainable production. At tilapia farms, high nutrient concentrations, water temperature and fish densities enhance bacterial growth including virulent bacterial clones and potential zoonotic bacteria. Global warming favours this. This review respectively provides a comprehensive overview of the most common and emerging bacterial pathogens, diseases, clinical presentations and diagnostics of tilapia, including bacteria and diseases with zoonotic potential. First, common bacterial disease outbreaks, including streptococcosis, motile Aeromonas septicaemia, francisellosis, columnaris disease and vibriosis are described. Then, information on emerging bacterial infections of concern for tilapia, like edwardsiellosis through Edwardsiella ictaluri and E. tarda, as well as Aeromonas schubertii is provided. Reports of infectious bacterial tilapia disease outbreaks from other bacteria, including Lactococcus garvieae, Aerococcus viridans, Pseudomonas spp., Mycobacterium marinum and Chlamydia spp., and others are reviewed. Furthermore, bacteria with zoonotic potential, like Streptococcus agalactiae ST283, S. iniae, Aeromonas sp., E. tarda, Vibrio vulnificus pathovar (pv) piscis and M. marinum are included in the review, to provide the most current overview of the disease risks affecting production and post-harvest stages. Additionally, the status and risks of antimicrobial resistance in bacteria from tilapia and other cultured fish through imprudent use of antibiotics, and its future at a global level are provided.This study was supported by two FAO projects namely: GCP/GLO/979/NOR: Improving Biosecurity Governance and Legal Framework for Efficient and Sustainable Aquaculture Production and GCP/GLO/352/NOR: Responsible use of fisheries and aquaculture resources for sustainable development, both funded by the Norwegian Agency for Development Cooperation (Norad)

AQD Matters 2022 November - December

In this issue: 1) SEAFDEC/AQD hosts 45th PCM; 2) AQD's research paper conferred with Dr. Elvira Q. Tan award; 3) Scientist emerita elected TWAS Fellow; 4) Malaysian university eyes collab with AQD; 5) Japanese professor keen on seaweed research; wants collab; 6) SEAFDEC/AQD scientist embarks on a research trip to Japan; 7) Meeting held to review SEAFDEC/AQD's accomplishments, discuss plans for 2023; 8) International training on community-based freshwater aquaculture held at Rizal; 8) GOJ sends AQD researcher to Japan for specialized training in seaweed; 9) Free books on aquaculture announced by AQD; 10) International online training for crab production; 11) Session 3 of AQD's intensive aquaculture training kicks off; 12) Christmas season at SEAFDEC/AQ

Production, feeding and storage of Tetraselmis tetrathele paste by electrolytic flocculation

An innovative microalgae harvesting technique using electroflocculation was carried out at different voltage treatments (4, 7, and 9 V) using a fabricated voltage regulator and compared with harvesting by electroflocculation at 12 V using a car battery to efficiently electroflocculate Tetraselmis tetrathele. This study was conducted to determine the ideal 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 7 V achieved low Pb content producing the best harvest biomass (1.4 kg, 87 min) which is comparable to the harvest biomass (1.7 kg, 68 min) using a 12 V car battery. Storage of T. tetrathele paste is best done in a chiller (2 ± 1 °C) rather than a freezer (-20 ± -4 °C) for ease in reactivation and maintaining higher cell viability for later use as a starter in aquaculture. Storage in a chiller allows T. tetrathele paste to be resuspended after six months and used as a starter culture.This study was funded by the Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD) Study code: Nr-01-Y2018T

Behavior changes and LC50 of dried garlic (Allium sativum) acute toxicity in Nile tilapia (Oreochromis niloticus) juvenile

Plant-based compounds are emerging substitutes for chemical treatments in aquaculture since they are known to cause less harm to both the environment and its organisms. Garlic (Allium sativum) is a popular herb that has a broad range of uses, especially in the control and treatment of bacterial and parasitic diseases. However, its toxicity to tilapia is not well-studied. Hence, this study was conducted to test the toxicity levels of garlic powder in juvenile Nile tilapia (Oreochromis niloticus) by determining the cumulative mortality and median lethal concentration (LC50). Test fish were exposed through immersion in 6 concentrations (150, 200, 250, 300, 350, and 400 mg L-1) of garlic powder with 25% allicin and a control in 96 h static bioassay. Within 24 h, test fish exposed to 250 mg L-1 garlic and above, exhibited abnormal behaviors such as lethargy, gasping for air, and weak responses to environmental stimuli. Cumulative mortality was highest at 100% in 400 mg L-1 garlic at 48 h. Mortalities were dependent on the concentration and duration of exposure. The 96 h LC50 of garlic powder to O. niloticus is 225.86 mg L-1 with lower and upper confidence limits of 210.37 and 242.50 mg L-1, respectively at 27°C.The authors thank the Government of Japan Trust Fund (Study Code: 8400-T-RD-FH0215) for funding this study. We are grateful to Dr. Evelyn Grace Ayson and Mr. Peter Palma for their valuable comments on the manuscript and technical assistance of Mr. Elvis Biñas