Southeast Asian Fisheries Development Center
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Gracilariopsis heteroclada as an extractive species in an aquaculture system
Get PDFThe study was conducted within the integrated finfish broodstock facility complex of SEAFDEC/AQD at Tigbauan, Iloilo, Philippines. The broodstock facility has a water recirculating system. The 500-ton capacity broodstock/spawning tanks were stocked with 25 grouper (Epinephelus coioides) and 90 milkfish (Chanos chanos) breeders. Water from the broodstock tanks passes through the sedimentation tank, then through the filter tank before it goes back to the broodstock tanks. The filter tank has an area of 20 m2, a water depth of 25 cm, and a water flow rate of 43 L sec-1 (≈3720 m3 day-1)
Cage culture of tropical eels, Anguilla bicolor pacifica and A. marmorata juveniles: Comparison of growth, feed utilization, biochemical composition and blood chemistry
No full textThis study examined the performance and suitability of two tropical anguillid eels, Anguilla bicolor pacifica and A. marmorata, under cage culture conditions. Juvenile eels (1.73 ± 0.14 g body weight) of each species were stocked in triplicate hapa net cages (1 × 1 × 1.5 m; 30 eels/cage) suspended in outdoor tanks. Growth, feed utilization, biochemical composition and blood chemistry of the two species were compared after 210 days. Except for survival, mean final body weight (FBW), weight gain percentage (WG), specific growth rate (SGR) and yield of A. bicolor pacifica (64.51 ± 13.07 g, 3514 ± 690%, 2.14 ± 0.12%/day, 1534 ± 380 g/m3) were significantly higher than that of A. marmorata (7.77 ± 2.90 g, 356 ± 125%, 0.89 ± 0.16%/day, 178 ± 89 g/m3). In comparison with A. bicolor pacifica, significantly lower feed intake (FI), feed efficiency (FE) and protein efficiency ratio (PER) observed in A. marmorata suggest the need to develop eel diets with feeding stimulants to improve feed acceptance. Biometric indices, body proximate and amino acid composition were not significantly different between the two species. However, serum glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and total protein (TP) in A. bicolor pacifica were significantly higher than that in A. marmorata. These findings suggest that the differences in growth performance and feed utilization between the two anguillid eel species are related to feed palatability, and that A. bicolor pacifica appears to be a suitable species for cage culture because of its faster growth.The Japan-ASEAN Integration Fund provided funds for the conduct of this study (Study code: Br-02-Y2018B)
AQD Matters 2021 November - December
No full textIn this issue: 1) Oplan Balik Sugpo progress reported to PH shrimp industry; 2) SEAFDEC/AQD attends online meeting for information staff; 3) 'Adoptable and sound' community-based freshwater aquaculture course; 4) Fish feed and nutrition training course, a hit among feed millers; 5) Two new publications launched, can be downloaded for free; 6) Farmers must understand the costs of tech-driven aquacultur
AQD Matters 2022 September - October
No full textIn this issue: 1) SEAFDEC renews push for pompano farming; 2) Scientist presents study in international conference; 3) AQD researcher joins RECAB activity on Gender; 4) Meeting convened to review, enhance SEAFDEC's information dissemination; 5) Seaweed researcher shares expertise to Indian researchers farmers; 6) Department of Agriculture's consultants visit SEAFDEC/AQD; 6) 700-kilogram stranded 'dugong' dissected, preserved; 7) Thematic, commodity meetings held; 8) SEAFDEC-assisted gov't nursery to boost aquaculture in Aklan; 9) Hundreds of milkfish broodstock undergo routine health checkup; 10) Trainings; 11) SEAFDEC/AQD conducts site visit to 3 marine hatcheries; 12) SEAFDEC/AQD at Agrilink/Foodlink/Aqualink 2022 expo and 24th Davao Agri Trade Exp
Rapid screening of potential probionts from the gut microbiota of climbing perch, Anabas testudineus
No full textThe intestinal microbial community has crucial functions for their vertebrate host. Several studies in fish showed that their gastro-intestinal tract harbors a diverse population of bacteria that supplies exogenous nutrients, enzymes, fatty acids and vitamins to their host. Most studies on probiotics involved their practical use for aquaculture, but are limited for the ornamental fish industry. Hence, this study aimed to screen the gut microbiota of a freshwater fish, Anabas testudineus, for potential probiotic candidates for the ornamental fish industry. Gut bacteria were obtained from the gut of climbing perch by plating of serially-diluted samples of the gut contents onto Nutrient Agar (NA). In vitro antagonistic activities of these gut bacteria against a fish bacterial pathogen, Aeromonas hydrophila, were determined by spot-on-lawn method. Isolates that had strong antagonistic activities against A. hydrophila were further characterized using standard staining and biochemical techniques. Rapid screening of the gut microbiota of climbing perch resulted in the identification of a promising probiont, Kurthia gibsonii through sequencing of its 16S rRNA gene. This bacterium is a member of the Planococcaceae family and is a Gram-positive, non-spore forming and rod-like bacterium. The isolate is yellowish in appearance and has a filamentous colony on nutrient agar. It exhibited catalase and amylase activities. Immersion challenge of freshwater ornamental fish with the bacterial isolate showed no mortality at 15 days after exposure. Taken together, the present study demonstrated that the gut microbiota of fish is a rich source of probiotic candidates that can be utilized during the culture of freshwater ornamental fish.This work is partly supported by the University of San Agustin Professorial Chair Research Grant titled, “Gut Microbiome: A Potential Source of Probiotic Candidates for Ornamental Fish” awarded to CMA Caipang. The authors of this paper would like to thank the support provided by their respective institutions; namely, the University of San Agustin and SEAFDEC Aquaculture Department during the preparation of the manuscript
Bacterial microbiota of hatchery-reared freshwater prawn Macrobrachium rosenbergii (De Man, 1879) and their pathogenicity
No full textQuantitative and qualitative analyses of bacterial microbiota associated with hatchery of Macrobrachium rosenbergii (de Man, 1879) were conducted over three larval cycles, along with important water quality parameters. Physicochemical parameters (temperature, DO, salinity, pH, and total ammonia) of culture water were within the optimum level required for the hatchery phase of M. rosenbergii. Significant differences in aerobic plate count (APC) among larval stages were observed. Ten genera and 17 species were identified with the predominance of Gram-negative bacteria constituting 63 % of all isolates (n = 706). A total of 17 dominant bacterial isolates randomly selected from freshwater prawn larvae were screened for in vitro hemolysin activity using blood agar plate (BAP) medium with 5% sheep blood. Pathogenicity of the isolated bacterial strains was assessed through in vivo infection bioassay. Out of the 17 isolates tested, six isolates showed α – β zone of hemolysis on the BAP, i.e., Aeromonas caviae, Bacillus cereus, Plesiomonas shigelloides, Staphylococcus warneri, Vibrio cholerae non-01, and Vibrio furnissii, were used in the infection bioassay. The current data indicate that the six bacterial isolates tested, particularly B. cereus and V. cholerae non-01, are opportunistic pathogens capable of inducing disease epizootics, particularly in freshwater prawn hatcheries with suboptimal rearing water conditions. Thus, control measures to reduce the influx of pathogenic microbes in the system by maintaining good water quality and good farm management practices through disinfection of culture facilities, rearing water, and Artemia cysts, the practice of good hygiene of personnel, regular water exchange, and feed regulation, among others, and cautionary use of antibiotics, can be adopted
Phytochemical composition antioxidant and antibacterial activity of the Philippine marine green alga (Ulva pertusa)
No full textThe phytochemical constituents, total phenolic and flavonoid contents, antioxidant and antimicrobial activities of the ethanolic extract of the marine green alga Ulva pertusa collected from floating fish net cages off the coast of Guimaras island, Philippines, were investigated. Qualitative phytochemical analysis revealed the presence of bioactive compounds including alkaloids, flavonoids, phenols, saponins, tannins, and terpenoids. Quantitatively, total phenolic and flavonoid contents of the extract were 20.54±2.08 mg gallic acid equivalent (GAE) g-1 and 539.07±6.36 mg rutin equivalent (RE) g-1, respectively. The antioxidant activity of the extract using 1,1-diphenyl-1-picrylhydrazyl (DPPH) assay exhibited a concentration-dependent radical scavenging capacity. Additionally, the ethanolic extract inhibited the growth of Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, Streptococcus agalactiae, Aeromonas hydrophila, A. sobria, and Vibrio harveyi in a concentration-dependent manner with strong inhibitory activity at 100 mg mL-1 concentration. Taken together, U. pertusa contains bioactive compounds that possess potent antibacterial activity and remarkable antioxidant capacities. These substances are promising candidates that may be utilized in the synthesis of novel drugs.This study was funded by the Government of Japan Trust Fund V through the Regional Disease Project (study code: FH01-F2010-T) and partly by SEAFDEC AQD
Improving artisanal fisheries through community-based prawn stock enhancement in a mangrove estuary
No full textTropical seafood, especially prawns, have always been in high demand with high market prices. Because of this, wild prawn resources are often overfished as indicated by the increasing number of fishers, but with overall declining catch volume and sizes through the years. Prawn aquaculture has, as of course, significantly contributed to the total yield in the past decades. However, the expansion of farms and ponds has often negatively affected the natural nursery grounds in the estuaries and mangroves. The economic gains from aquaculture are limited only to those who invested. However, local communities and artisanal fishers are often deprived of such gains. They are still reliant upon the dwindling natural stocks of fisheries resources. This is where the concept of stock enhancement comes in, wherein hatchery-produced juveniles are released into the water body in order to increase capture fisheries yield for local fishers.
In this talk, I will present the case of the tiger prawn Penaeus monodon stock enhancement in the New Washington Estuary (NWE), in Aklan, central Philippines. The NWE was a productive fishing ground providing >24 kg/gear/day of catch in the 1970s but steadily declined to 400%. However, in order to sustain the prawn fisheries and optimize the benefits, long-term management plans by all stakeholders are needed, especially between the communities and the local government
Occurrence and disappearance of a non-native goby Rhinogobius sp. OR in relation to hydrological conditions in the Kamo River, southwestern Japan
No full textWe monitored the abundance of a non-native (Rhinogobius sp. OR) and two native stream gobies (R. fluviatilis and R. nagoyae) over a decade, from 1995 to 2004, in a fixed reach of a tributary of the Kamo River, southwestern Japan. The non-native Rhinogobius sp. OR appeared and reproduced in 1997, when an increased deposition of fine sediments occurred. However, after a severe spate in 1999, the non-native goby almost completely disappeared from the study reach, while the density of the native R. fluviatilis increased. The severe spate is likely to have prevented the establishment of the non-native goby. Our results provide an example of abiotic barriers to invasion