Southeast Asian Fisheries Development Center
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A system of microalgal harvesting with reduced Pb in Chaetoceros calcitrans paste
No full textThe invention relates to the protocol for harvesting of microalgae, Chaetoceros calcitrans by manipulation of electrolytic flocculator settings. The harvesting system comprised of a holding tank for the microalgae, a DC power supply with variable voltage selector, ammeter and voltmeter. The best settings of 6/6 units Al/Pb probes with voltage selector set at point 1 to supply 3 volts to complete the electrolytic cell. The Pb in the paste was reduced by 97% with values of 34.27 ± 0.39 ppm with 0 - 0.24 ppm Pb in the effluent discharge. The Pb content in secondary live food, Artemia salina was further reduced by 78% based on feeding trials with 7.8 ± 5.1 ppm Pb content. This system will be beneficial to hatcheries for use onsite due to its simplicity and affordability
A process of culturing mud polychaete Marphysa iloiloensis
Full text linkThe present invention is a culture process for the larval rearing of mud polychaete Marphysa iloiloensis (from 1 DAH to 30 DAH). The process involves the use of fresh bioflocs as the first food source and settlement substrate of the polychaete larvae. Larval rearing was located in a shady area (0 to 50 lux) and aerated, UV-treated seawater was recirculated in the larval rearing tanks. Using this invention, 83.29 ± 3.79% of the larvae survived with 21± 1 segments after 30 days of larval rearing
Hatchery protocol for silver therapon (Leiopotherapon plumbeus, Kner 1864)
No full textThe hatchery protocol for silver therapon (Leiopotherapon plumbeus, Kner 1864) in outdoor tanks is disclosed. The process includes timed provision of preferred natural food commensurate with the age of larvae, pre-conditioning of rearing water, utilizing ambient lake water and the addition of fresh tropical almond leaves Terminalia catappa to enhance natural food supply in tanks. A stocking density of 0.1 to 1 larvae /L was used to enhance survival and growth. Survival of larvae increased to 35.41 ± 15.32 per cent using the invention
A method of culturing/ growing high-quality edible oysters (Crassostrea spp. and Magallana bilineata)
Full text linkThis utility model discloses a process of culturing/ growing high-quality edible oysters (Crassostrea spp. and Magallana bilineata) comprising the steps: selecting grow-out culture sites, deploying substrates for competent larvae of oysters to settle and grow, making oyster pouches while waiting for the availability of oyster spat, harvesting and stocking the oyster spat in the said pouches, hanging the pouches from rafts, and harvesting the oysters when they attain at least 80 grams of body weight. Traditional processes of producing edible oysters allow them to grow on top of each other, producing clumped oysters of varying sizes. This utility model produces larger, individual oysters of almost uniform sizes with harvest size attainable at a shorter period compared to those oysters cultured using traditional methods
A special feed for maturing Penaeus indicus broodstock
Full text linkThe present utility model relates to a special feed for maturing Penaeus indicus broodstock comprising of 55% protein and 12% lipid. The said formulation per 100 grams is further comprising of: Shrimp meal (19.7 -24.6g), Danish Fish meal (19.7-24.6g), Squid meal (19.7-24.6g), Cod liver oil (0-13g), Cholesterol (1.0g), Wheat flour (7.2-14.9g), Gluten (6.0g), Vitamin mix (2.0g), Vitamin C (1.0g), Choline chloride (1.0g), and Mineral mix (2.0g). The said special feed promotes gonad maturity and egg diameter and is comparably effective than using fresh maturation diets. The special feed has a survival rate of 90-96% which is relatively higher compared to the usual 93%. Specific growth rate per daily basis (SGR (%day-1) is at 23-24% while the Maturation Rate is at 50-55% which means the growth of the fish is now directed toward gonadal maturation
Evaluation of cultivation potential and carrageenan properties of Hypnea sp. from Panay Island, Philippines
No full textLink to the electronic supplementary material.Hypnea is a cosmopolitan genus of red seaweeds and an important source of carrageenan worldwide. However, Hypnea species remain largely unutilized in seaweed aquaculture in the Philippines. This study aimed to evaluate the growth performance and carrageenan properties of an indigenous, unexploited Hypnea sp. collected from Panay Island and to compare them with those of the commercially cultivated Kappaphycus striatus. In a field cultivation experiment, Hypnea sp. showed significantly higher biomass (145.1 ± 53.7 g) than K. striatus (92.9 ± 10.3 g) up to day 28 (p < 0.001), while no significant difference was observed at days 36 and 43. The final yields were 181.0 ± 68.4 g for Hypnea sp. and 191.1 ± 33.0 g for K. striatus (p > 0.05). Semi-refined carrageenan extracted from the cultured Hypnea sp. exhibited gel-forming capacity, suggesting the presence of κ-carrageenan. However, both the viscosity and gel strength of Hypnea sp. (9.52 ± 3.53 cP; 148 ± 41.6 g cm⁻2) were significantly lower in K. striatus (70.9 ± 49.4 cP; 456 ± 201 g cm⁻2) (p < 0.001), indicating that Hypnea sp. possesses distinct carrageenan properties from conventional commercial seaweed. Although further development of carrageenan-based products tailored to its unique properties will be required for commercial utilization, these findings highlight the potential of Hypnea sp. as a candidate seaweed for aquaculture in the Philippines.Open Access funding provided by Japan International Research Center for Agricultural Sciences (JIRCAS). This study was supported by the Japan International Research Center for Agricultural Sciences under the 5th Medium to Long-Term Plan and implemented at SEAFDEC/AQD with a Study Code: FS-01-S2023T
Bioflocs-assisted mass culture of Brachionus plicatilis under prolonged zero-water exchange and its application to Pagrus major larviculture
No full textThe sustainable mass production of rotifers is crucial to sufficiently supply marine fish hatcheries. However, maintaining a stable rotifer culture is still a challenge mainly due to unionized ammonia (NH3) toxicity and biological contaminants. This study investigated the effectiveness of single initial inoculation of bioflocs (BF) in addressing the abovementioned problems on rotifer mass culture using Brachionus plicatilis subjected to three treatments for 29 days, namely: 1) water exchange (WE), 2) zero water exchange (ZE), and 3) bioflocs × zero water exchange (BF × ZE). The effects of feeding BF-cultured B. plicatilis and supplementing BF in the rearing water on the survival and growth of red sea bream Pagrus major larvae for 14 days were evaluated. Bacterial composition of BF was determined. BF inoculation resulted in significantly higher rotifer densities from day 14 to day 29 (BF × ZE with 226–434 individuals/mL vs WE and ZE with 69–131 individuals/mL). BF inoculation significantly controlled ciliate contamination (BF × ZE with 7–25 ciliates/mL vs ZE with 421–531 ciliates/mL) from day 21 to day 25. TAN and NH3 concentrations were significantly reduced in the BF × ZE than in ZE and WE treatments on day 29. P. major larvae fed BF-cultured rotifers and reared in BF-supplemented water did not show reduced survival and growth. BF inoculation significantly improves B. plicatilis productivity through the effective removal of NH3 via the ammonia-oxidizing activity of Nitrosomonas nitrosa and bacteria within the phylum Chloroflexota under prolonged zero-water exchange conditions. Furthermore, the study demonstrates the viability of BF in P. major larviculture.The first author is thankful to the Ministry of Education, Culture, Sports, Science and Technology (MEXT) for the Ph.D. scholarship
First report on the use of various fishing gears and transport schemes for the captive breeding of shortfin scad (Decapterus macrosoma) as a potential species for aquaculture
No full textThis study establishes the first protocols for the live capture and transport of shortfin scad (Decapterus macrosoma), a potential new species for aquaculture. Wild fish were collected in the central Philippines using different fishing gears (ring net, otoshi-ami, hook-and-line), held for conditioning in a temporary cage, and transported using polyethylene bags or a customized chilled tank. While 3-day post-transport survival varied widely (1.5–100 %), a key finding was that a prolonged conditioning period prior to transport was essential for achieving high (100 %) survival rates, regardless of the capture method or transport system used. This research provides a critical foundation for supplying healthy broodstock to initiate captive breeding programs for shortfin scad.This research was made possible through the funding from the Japanese Trust Fund with study code BR-02-F2020T and the facilities provided by the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD)
Viral load differences associated with infection outcomes and resistance to white spot syndrome virus (WSSV) infection in mud crab, Scylla serrata
No full textWhite spot syndrome virus (WSSV), the causative agent of white spot disease, remains a serious threat to crustacean aquaculture. Infecting a wide range of crustaceans, host species exhibit varying susceptibility and mortality rates. Mud crabs, Scylla serrata, a high-value aquaculture commodity across the Indo-Pacific region, are known to be relatively resistant to WSSV. However, there is limited information on the progression of WSSV infection in the species which can provide insight into mechanisms of resistance. Employing a time course experimental challenge of S. serrata with WSSV, this study characterized viral load dynamics in juveniles over a period of 144 h post infection (hpi) in relation to (1) disease outcomes (survival or mortality); (2) distribution among tissue types (gills, gut, hepatopancreas, and hemolymph); and (3) variability between two different juvenile cohorts. Viral load progression suggests that WSSV resistance in mud crabs may be due to two distinct mechanisms. One mechanism involves the capability of S. serrata for viral clearance following active viral replication. Viral growth in S. serrata demonstrates three phases: early stage or onset characterized by minimal change in viral load (0 to 24-hpi), logarithmic stage of active replication with rapid increase in viral copy number (24 to 72-hpi), with the third phase (96–144 hpi), exhibiting differential patterns with infection outcome. Dead crabs exhibited a plateau phase where viral loads remained similar to peak levels, while crabs that were still alive beyond 96 hpi exhibited a resolution phase, characterized by reduction in viral load, returning to non-infected levels. Another apparent mechanism for WSSV resistance involved overall inhibition of replication, with recalcitrant individuals exhibiting markedly low viral loads at expected logarithmic infection phase timepoints (48–72 hpi). This study also revealed tissue tropism of WSSV in S. serrata. Gills appear to be the primary site of WSSV replication, exhibiting the highest viral load from the early to peak stages of infection compared to other tissue types such as the gut, hepatopancreas, and hemolymph. The establishment of viral load curves to track the progression of WSSV infection, and characterization of viral abundance across different tissues through the course of infection, represents novel information that has key implications on the role of S. serrata as carriers/vectors of WSSV. This may have practical implications for disease mitigation measures for aquaculture facilities, and development of new strategies to prevent and reduce pathogen infection in mud crab to support sustainable aquaculture production
Application of predatory bacteria (Bacteriovorax sp.) as a biocontrol agent against the pathogenic Vibrios in Pacific whiteleg shrimp (Penaeus vannamei)
No full textVibriosis, a bacterial disease, is considered a significant threat to the sustainability and economic viability of shrimp production. The present study evaluated the application of a predatory bacterium to control the population growth of pathogenic Vibrios in Pacific whiteleg shrimp (Penaeus vannamei). The predatory bacterium was identified as Bacteriovorax sp. OP175948.1 based on the 16S rRNA sequence. The Vibrio-inhibitory activity of Bacteriovorax sp. was evaluated using two independent trials with P. vannamei, exposed to two pathogenic Vibrios, including Vibrio parahaemolyticus and Vibrio harveyi. Each trial was conducted in five treatments, including a negative control, a positive control, and a treatment with Bacteriovorax sp. applied at 102, 104, and 106 plaque-forming units mL−1 (PFU mL−1). Results indicated that shrimp infected with V. parahaemolyticus and V. harveyi, and then treated with Bacteriovorax, showed a 6-fold increase in survival for V. parahaemolyticus and a 3-fold increase for V. harveyi, relative to the control. The shrimp treated with 104 to 106 Bacteriovorax sp. improved survival associated with a significant decline in Vibrio spp. counts in the shrimp tissues and rearing water. The Bacteriovorax sp. should be used as a practical strategy to prevent Vibrio-associated mortalities in P. vannamei aquaculture.This work was funded by the Department of Science and Technology Accelerated Science and Technology Human Resource Development Program (DOST-ASTHRDP) and ride-on research by the University of the Philippines Visayas DOST Shrimp Breeding Project (UPV-DOST Development of WSSV-resistant and fast-growing strain of P. vannamei through selective Breeding)