Organized by SEAFDEC Aquaculture Department with funding from the Government of Japan, the 3-day International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia aims to promote and augment regional initiatives on resource enhancement and sustainable aquaculture practices, and to contribute to poverty alleviation, livelihood and food security.

Recent Submissions

  • Book | Conference publication

    Resource enhancement and sustainable aquaculture practices in Southeast Asia: challenges in responsible production of aquatic species : proceedings of the international workshop on resource enhancement and sustainable aquaculture practices in Southeast Asia 2014 (RESA) 

    MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.) - 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The conference was held in order to promote and augment regional initiatives on resource enhancement and sustainable aquaculture practices, and to contribute to poverty alleviation, livelihood and food security in Southeast Asia. The contributions of the selected participants during the conference which are contained in this volume are cited individually.
  • Conference paper

    Good aquaculture practices (VietGAP) and sustainable aquaculture development in Viet Nam 

    TBT Nguyen - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The shrimp (black tiger and white leg shrimp) and catfish industries in Viet Nam continue to experience increasing growth due to rapid aquaculture development. However, disease outbreaks become a major issue. Moreover, seafood consumers at present are likely to be more concerned about how the products are produced and how to control/manage aquatic animal health instead of treatment. Hence, the main objective of this abstract is to focus on one of the solutions to address these problems/issues and ensure sustainable aquaculture development in Viet Nam.
  • Conference paper

    A preliminary study on the diagnosis of coral reef healthiness and establishment of coral replenishment technology 

    T Azuma, JJR Tan, J Zarate, J Altamirano, J Gatus & F Sotto - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Field surveys for coral reef through line-intercept-transect (LIT) and temperature profiling using data-loggers were done at three layers of 5, 10, and 15 m depths in coral reef areas, Nogas Island, Anini-y, Antique, Philippines. Preliminary data based on the LIT survey showed that both coverages of substrates by any type of organism and by Scleractinia decreased in the deeper layers. For Scleractinia, Porites sp. occurred predominantly in all the depth layers with the occurrence decreasing with depth. Temperature fluctuation was largest in the 5 m depth layer, where effects of tidal level were also confirmed. While the average temperature decreased with depth, this did not differ beyond 1°C between 5 and 15 m layers during November 2012 to March 2013. Fragments of the Porites sp. and Acropora sp. were sampled and transferred to aquaria at the Tigbauan Main Station of SEAFDEC/AQD. Acropora sp. sampled from the deepest layer alone showed bleaching and thereafter, a part of the fragments regained the color. Experimental trials to clarify the effects of ocean acidification and warming on the health of the coral using the live fragments of Porites sp. showed decreasing trends in both photosynthetic rates and daily growth rates in acidic condition (pH = 7.6), while decrease of zooxanthellae density was observed under warmer conditions (31°C ) for one month. A new methodology for the determination of density of zooxanthellae was established using the fragments of Porites sp. In this study, the need for studies on several coral communities as well as further basic research on coral biology, particularly, responses to the changing environments are discussed for diagnosis of coral reef healthiness and establishment of effective coral replenishment technology.
  • Conference paper

    Reproductive biology of christian crabs (Charybdis feriatus, Linnaeus, 1758) in San Miguel Bay, Philippines 

    PM Nieves, NR Olfindo & AM Macale - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The reproductive biology of Charybdis feriatus was investigated from April 2012 to March 2013 to determine gonad maturity, gonado-somatic index (GSI), fecundity, breeding cycle and size at first maturity. Every month, samples of 30 specimens were randomly collected. Gravimetric and volumetric methods were used to estimate fecundity. Results showed that Charybdis feriatus breeds continuously with a distinct period of reproductive activity during the northeast monsoon. Spawning peaks in January where higher values of GSI, mature, and berried female crabs were observed. Female gonad (ovary) weights range from 0.5 to 18.1 grams while mean GSI of female and male were 7.35% and 6.27%, respectively. Berried females were present year round, the highest occurring in December (50%). Fecundity ranged from 1,513,660 to 6,357,133 eggs. The smallest reproductively active female was 8.3 cm. Fecundity was highly correlated with size (r2=0.92).

    In view of these observations, the following options are recommended for crab fishery resource management: (1) to set a closed season for crab fisheries, (2) to regulate catches by not taking egg-bearing swimming crabs, and (3) to allow egg-bearing crabs to release its eggs and the larvae in fishing grounds and/or marine protected areas.
  • Conference paper

    Feed formulation for sustainable aquaculture 

    RM Coloso - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    As aquaculture production of tropical fish and crustacean species becomes more intensified, practical diets need to be formulated to be cost effective and environment-friendly. Ingredients should be included to satisfy the nutrient requirements of the animal, promote optimal fish growth, and boost the income of small-scale farmers and commercial producers with minimal impacts to the surrounding environment. Feed formulation for sustainable aquaculture should aim at increasing aquaculture system performance and profitability, enhancing the animals disease resistance, increasing attractability, palatability, and digestibility of practical diets, and maintaining environmental quality through sound feeding management and good aquaculture practices. More vigorous research and development efforts need to be supported to generate feed technologies that will ensure a steady and reliable supply of safe and high quality aquaculture products to the public while preserving the environment.
  • Conference paper

    The importance of mangroves to capture and culture fisheries 

    JH Primavera - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Abstract only.
  • Conference paper

    Stock assessment of christian crabs (Charybdis feriatus, Linnaeus, 1758) in San Miguel bay 

    PM Nieves, NR Olfindo & AM Macale - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Assessment of the status of swimming crab fisheries in San Miguel Bay with focus on Christian or Crucifix crab, Charybdis feriatus, was undertaken from November 2011 to January 2013. An analytical length-based fish stock assessment was employed using the FISAT (version 1.2.2). A total of 7,679 length frequencies (3,612 C. feriatus and 4,067 Portunus pelagicus) were used in the analysis. About 15 and 14 percent gravid females were harvested monthly for both species that may contribute to recruitment overfishing. Population parameters showed exploitation rate (E) for P. pelagicus and C. feriatus exceeded the optimum exploitation (E0.5) implying excessive fishing effort and heavily exploited stocks. Size at maturity of C. feriatus and P. pelagicus in San Miguel Bay is 8.3 cm and 8.5 cm, respectively. Doable options for resources conservation and management strategies are proposed and supported by local government units (LGUs) including the Integrated Fisheries and Aquatic Resource Management Council.
  • Conference paper

    Potential of cowpea (Vigna unguiculata L.) meal as an alternative protein source in diets for giant freshwater prawn (Macrobrachium rosenbergii, de Man 1879) 

    FA Aya, ML Cuvin-Aralar & RM Coloso - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Growth trials were conducted to evaluate cowpea Vigna unguiculata (L.) meal as a potential protein source in diets for giant freshwater prawn, Macrobrachium rosenbergii (de Man 1879), reared in tank and lake-based cages. Five isonitrogenous (approximately 37% crude protein) and isocaloric diets were formulated where fish meal (FM) protein was replaced with 0%, 15%, 30%, 45% and 60% cowpea meal protein (or CP0, CP15, CP30, CP45, and CP60, respectively). Results of an 8-week tank trial showed that the final body weight (FBW), percent weight gain, specific growth rate (SGR) and survival of prawns were not significantly influenced by dietary treatments (P > 0.05), although the highest values, except for survival, were observed with CP45. In a lakebased cage trial that lasted for 16 weeks, prawns fed CP30 and CP45 had significantly higher FBW (13.1 and 14.4 g, respectively) compared to other treatment groups (P < 0.05). SGR (4.52 5.00%/ day), survival rates (53-77%), yield (98.5-116.5 g m-2) and feed conversion ratio (FCR; 2.0-2.7) were not affected by increasing levels of cowpea meal in the diets. Based on these results, cowpea meal can be considered as an alternative protein source in diets for M. rosenbergii.
  • Conference paper

    Seed production of the blue swimming crab (Portunus pelagicus) 

    NS Cabacaba & JE Salamida - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The blue swimming crab, Portunus pelagicus, is becoming a commercially important species in the Philippines. The expanding export market for crabs has led to intensified collection and has threatened the wild stocks. This decline has prompted the need for proper management of the remaining resources, and interest in the establishment of hatchery facilities to produce crablets for reseeding and aquaculture.

    This paper presents the production method for P. pelagicus seedstock at the Guiuan Marine Fisheries Development Center. Experiments to improve larval rearing were conducted as well. For seed production, larvae at the zoeal stage were taken from wild-caught berried crabs hatched in 100-L circular drums filled with sand-filtered seawater (32-34 ppt, 28-30°C). Zoeae were stocked at 100 zoea L-1 in rectangular tanks and fed rotifers at 30 ind ml-1 for the first 4 days. Newlyhatched Artemia were given at 1-2 ind ml-1 at zoea 3, and increased to 5 ind ml-1 at zoea 4 to the megalopa stage. Chlorella sp. was maintained in the rearing tanks at 50,000 cells ml-1 as food for rotifers and for water conditioning. Water exchange was done daily at 30-50%, except for the first 5 days of rearing. The development from zoea 1 to megalopa and megalopa to the first crab instar took 10-12 and 4-6 days, respectively. Longer larval development was observed at lower temperature (<26°C). Cannibalism and deteriorating water quality were identified as major causes of mortality. Survival of zoea 1 to megalopa was higher in chlorinated seawater (7.5+2.58%) compared to UV-treated (6.5+1.73%) and sand-filtered (4.0+2.58%) seawater. Trials involving the use of different tank background colors showed that the survival of larvae was highest in black tanks (9.0+1.00%) as compared to those white tanks (1.5+0.58%).

    In nursery rearing, megalopae were stocked at 1-2 ind ml-1 in wide tanks or concrete pond. Strategies to reduce cannibalism were done by providing shelters and sand substrate (>10 cm). As soon as the megalopa molted to crab instars, they were given minced fish, shell meat, Acetes and formulated crab feeds twice daily, ad libitum. After 21 days, crablets were collected manually after partially draining the water in concrete pond. The crablets produced were released in identified fish sanctuaries and marine protected areas region-wide for resource enhancement and for aquaculture research purposes.
  • Conference paper

    Perceptions on the effects of maritime activities on the Philippine aquatic ecosystem 

    E Java, T Cruz & IY Hernandez - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Throughout history, humans create an impact on marine ecosystems. May it be positive or negative, such impact is long-term and shapes the overall image of the system. As humanity increases its number, so does the impact it creates. Humanity has relied on the oceans for food, recreation and for various economic opportunities. Overfishing and pollution affects the life in the seas. Advancements in fishing technology, such as tracking technologies and better transportation have reduced fish stocks significantly when matched with non-sustainable practices, such as dredging and trawling. Intentional dumping from sewages, industrial run-off and chemicals has brought about pollution in the seas. Though some pollution may be accidental, like oil spills, it still causes adverse effects to the sea. Excess nutrients coming from fertilizers and intensive farming practices have resulted to what is known as eutrophications. Lastly, changes in the marine environment have led to the introduction of invasive alien species and marine organisms, which are oftentimes difficult to eradicate. Such effects have made researchers rethink of various ways to maintain marine activities while sustaining its ecosystem.

    Through this study, the researchers determined the effects of maritime activities on the population of aquatic creatures directly from the seafarers, and found out their perspectives on how to remedy such effects and sustain the marine ecosystem.

    This research is descriptive in nature, conducted with 100 purposively selected seafarers from Manila. The participants were given a questionnaire that asked for demographics and their perceptions on the effects of maritime activities on the marine ecosystem and ways to provide solutions to minimize or avoid its negative impacts.

    Findings show equal distribution on gender, with majority at the low socioeconomic level (47%) and are Tagalog in ethnicity (56%). The seafarers believe that the maritime activities cause harm on aquatic creatures (43%), limits propagation of aquatic species (36%), makes them prone to mortality (11%) and cause pollution to the atmosphere (10%). Likewise, their perception of minimizing the consequences lies within the proper conditioning of ships and running them in good condition (57%), maintaining a clean place for the marine inhabitants (28%) and creating a good waste-renewal system (15%). The results of the paper is directed towards proper handling and maintenance of the shipping industry and strict supervision for waste management.
  • Conference paper

    Optimization of feeding and growth conditions for hatchery-bred larvae of indigenous Philippine silver perch, Leiopotherapon plumbeus (Perciformes: Terapontidae) 

    JA Añano, F Aya, MN Corpuz & MRR Romana-Eguia - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The Philippine silver perch, locally known as ayungin, is an endemic fish species and is considered as a potential candidate for aquaculture and for stock enhancement. However, high mortality associated with early larval stages presents a significant bottleneck to its latent commercialization. Culture experiments considered interactions among prey proportions, growth conditions and their consequences on fish growth performance and survival. Two phases of the experiment were conducted: (1) a short duration feeding trial utilizing different prey proportions of Brachionus calyciflorus and Moina macrocopa and (2) an indoor larval rearing technique that ensured optimum growth and survival of juveniles. Findings of this research will be used to propose an efficient rearing strategy addressing the aquaculture of this indigenous species.
  • Conference paper

    Marker-aided genetic stock management: prospects in Philippine aquatic biodiversity conservation and aquaculture 

    MRR Romana-Eguia, M Ikeda & A Kijima - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    With the advent of DNA marker-based technologies and applications, genetic stock assessment incorporating molecular marker information has become an important tool in managing resources both for aquaculture and stock enhancement. Local initiatives toward this end have been undertaken by several research and academic agencies particularly those with access to advanced molecular genetic laboratory facilities both in the Philippines and in collaborating foreign institutions. Funds coming from the Philippine Department of Science and Technology and/or international research grants have supported work on commercially valuable species such as tilapia, shrimp, mud crabs, abalone, milkfish and some high value marine fishes with a view of utilizing and in the process, demonstrating the significance of more scientific microlevel assessment of stocks. Information drawn from marker-aided genetic stock evaluation can contribute to a better understanding of the impact of how proper stock management can be more effectively achieved and how this method can gradually translate to improved yields both from culture and fisheries. This paper covers a review of the status of this technology as applied to ongoing fish conservation and aquaculture production efforts in the Philippines.
  • Conference paper

    SEAFDEC/AQD stock enhancement initiatives: release strategies 

    MJH Lebata-Ramos, EF Doyola-Solis, R Sibonga, J Sumbing, JB Abroguena, A Santillan & M Dimzon - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD) started its Stock Enhancement Program more than a decade ago with the first stock enhancement initiative on the mud crab Scylla spp. funded by the European Commission. This was followed by another stock enhancement program in 2005 supported by the Government of Japan Trust Fund. In preparation for its implementation, a Regional Technical Consultation on Stock Enhancement of Species Under International Concern was convened in Iloilo City, Philippines in July 2005 to identify species for stock enhancement. During the meeting, seahorses Hippocampus spp., giant clam Tridacna gigas, abalone Haliotis asinina, and sea cucumbers Holothuria spp. were among the priority species for stock enhancement work.

    Stock enhancement, restocking and ranching are management approaches involving the release of wild or hatchery-bred organisms to enhance, conserve or restore fisheries. This paper reports SEAFDEC/AQD release activities and some of the release strategies that have been established for mud crabs, giant clams and abalone.
  • Conference paper

    Induced breeding of giant trevally, maliputo (Caranx ignobilis) 

    MTM Mutia, FB Muyot & ML Magistrado - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The giant trevally, maliputo (Caranx ignobilis), a highly prized and most popular indigenous migratory fish in Taal Lake, Batangas, Philippines, was induced to spawn using various hormones (to assess hormone efficacy on spawning performance). Different feeding regimes used in the larval rearing of this species were also evaluated. Sexually mature breeders, 5 to 7 years old with at least 0.5 mm oocyte diameter and 60% of ova at GVM stage were injected intramuscularly, in two doses, with: (a) 1,000 IU/kg BW human chorionic gonadotropin (HCG); (b) 100 µg/kg BW luteinizing hormone releasing hormone analogue (LHRHa); and (c) 5 mg/kg BW carp pituitary extract (CPE), at five breeders per hormone treatment. Uninjected fish served as the control. Treated fish were released and allowed to spawn spontaneously in 40-ton (5m diameter) circular tanks.

    Successful spawning was achieved during the months of March to July (28-30 ppt salinity; 27.6-29.25°C). Maliputo eggs are pelagic, clear and spherical, with a single oil globule and mean diameter of 0.8 mm. Ovulation period was 24-36.5 hours after 2nd injection in HCG-treated fish and 25-52 hours for LHRHa-injected fish. Only one of the CPE-treated fish spawned after 27 hours but eggs were not fertilized. Uninjected control fish did not spawn. Eggs were hatched in 11-13 hours in HCG treatment and 11-17 hours in LHRHa. Mean number of spawned eggs (3,500-4,000 eggs•gram-1) was higher in HCG treatment (223,068 eggs•kg-1 breeder at 58.27g•kg-1 breeder) than LHRHa (176,524 eggs•kg-1 breeder at 50.44 g•kg-1 breeder). Fertilization and hatching rates were both higher in LHRHa (60.88% and 71.07%, respectively), than HCG treatment (30.53% and 43.06%). Mean number of produced larvae was higher in LHRHa treatment (56,040 larvae•kg-1 breeder) compared to HCG-treated fish (41,547 larvae•kg-1 breeder).

    Hatched larvae (1.6 mm mean length) reared for 30 days in 3m x 3m concrete tanks using the standard protocol for marine finfish hatchery attained a maximum survival of 4.47%. Complete metamorphosis was observed after 26-28 days (8.1 mm mean length). Successful larval rearing was attained using greenwater (Nannochloropsis sp.) technology fed with live food (Brachionus sp. and Artemia salina). Critical periods were days 1-7 and days 19-22 when heavy mortalities were observed.

    Being the first recorded spawning in captivity of Caranx ignobilis in the Philippines, the results of this study provides an important baseline data and is a major step towards the development of a hatchery technology for maliputo in the country as well as for seed enhancement of its natural habitat. The project has provided 400,000 maliputo larvae to private hatcheries for larval rearing trials while 100,000 larvae were seeded in Balayan Bay and 5,000 fingerlings released in Taal Lake.
  • Conference paper

    Current status of aquaculture in Singapore 

    NC Heng - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Singapore is a small country state with a demographic profile of over 5 million in population. With limited land for agricultural purposes and sea space available for fish farming, Singapore depends heavily on importation of fresh seafood. Even so, Singapore has a small but thriving and increasingly important food fish farming industry which accounts for about 6% of local food fish consumption.

    The main bulk of local food fish production comes from coastal farming in floating netcages along the northern coast of Singapore. Popular species of marine food fish cultured include seabass, pompano, groupers, mullets and milkfish. There are also a few land-based fish farms culturing species like tilapia, marble goby and snakehead.

    The ornamental fish farming industry is concentrated mainly in Agrotechnology Parks and there are about 75 fish farms producing ornamental fishes with an approximate value of $76.7 million that is exported to over 80 countries.

    The Agri-Food and Veterinary Authority of Singapore (AVA) is the national authority for aquaculture development in Singapore and manages aquaculture farms through the issuance of fish farming licenses. For marine food fish farms, the farm licensee has to abide by good farm management guidelines to maintain the farm in good condition and ensure that the farm does not engage in activities that would impact the farming environment. For land-based farms, there are also guidelines that address infrastructure layout, farming system and water treatment facilities. The latter requires that sedimentation ponds, reservoir ponds/tanks, supply/drainage systems and trade effluent treatment plant are included in the farm set-up.

    There are several challenges and issues faced by the aquaculture industry in Singapore. One of these is the consistent supply of good quality fish fry as farmers have to source for fish fry from overseas sources that may not be consistent or readily available.

    Issues of fish health and farm management are other challenges faced by our fish farms. These factors affect farm productivity and the sustainability of farming operations.

    The AVA has established the Marine Aquaculture Centre (MAC) on St John's Island to address the needs of aquaculture development for Singapore through development of fish reproduction and seed production as well as large-scale fish farming technology. At present, the fish reproduction technology research work involves closing the reproductive cycles of key marine food fish species and also fry production at a commercial scale level. Closing the reproductive cycle will help to reduce the reliance on imported fry. Good quality brooders are selected, maintained and bred to produce quality fry, which would translate to better growth performance and shorter culture period. This, together with good farm management practices, will optimize the usage of fish feeds during the culture cycle.

    To fill the gap in production and supply of good quality fish seeds for local fish farms, AVA shares information on hatchery technology development with local commercial hatcheries.

    The AVA collaborates with research institutes and local fish farms in the development of vaccines to boost the survival rate of fish fry and fingerlings. This will improve survivability, thus increase the production of the farms and reduce the reliance on prophylactic drugs that may have negative consequences from prolonged use.

    The AVA also renders technical assistance to the farmers to formulate viable production plans to improve production. By leveraging on the use of technology and good farm practices, such as implementation of fish health, fish nutrition and feeding protocols, it is possible to reduce production costs and improve productivity. The introduction of the Good Aquaculture Practice scheme for food fish farming will help improve the standards of the local aquaculture industry and sustainability through responsible management practices.
  • Conference paper

    Preliminary trials on the effects of weaning and larval diets on survival and growth of silver therapon (Leiopotherapon plumbeus) larvae 

    FA Aya, VSN Nillasca & LMB Garcia - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Success in larval rearing of silver therapon can be achieved through early weaning of fish larvae from live food to artificial diet. Two experiments were carried out to investigate the effects of (a) weaning age (abrupt and gradual) and (b) larval diets (artificial and live foods) on survival and growth of silver therapon (Leiopotherapon plumbeus). In the first experiment, larvae were randomly stocked in round 4-l plastic basins at 15 larvae per basin to provide triplicates of four weaning age treatments (8, 14, 20 and 26 days after hatching or DAH, respectively). Larvae were fed thrice daily for 21 days with commercial feed (CF) and with copepods (COP) which served as the control. Larvae weaned at 26 DAH had the highest survival, body weight and total length among the treatment groups, which were comparable with that of the control. In the co-feeding protocol, larvae were fed Artemia nauplii (ART) as the control group and co-fed with either zooplankton i.e. 50% COP + 50% CF or 50% ART + 50% CF for 8 (8-15 DAH), 6 (14-19 DAH) and 4 (20-23 DAH) days, and suddenly weaned to FM until 21 days. Survival ranged from 22.2 ± 16.8 to 40.0 ± 24.0% between treatments, but was still lower than the control (88.9 ± 3.8%). Body weight and total length were significantly higher in larvae with co-feeding for 4 days (70.1 ± 2.8 mg; 18.1 ± 0.8 mm), but were still lower than that of the control (142.8 ± 7.6 mg; 22.3 ± 0.3 mm).

    In the second experiment, 26-day old larvae were stocked in 20-l glass aquaria at 4 larvae l-1. Larval diets ((I) commercial prawn feed (38% crude protein); (II) Artemia nauplii; (III) copepods; and (IV) free-living nematode Panagrellus redivivus) were given twice daily for 28 days. Survival was highest in larvae fed Artemia nauplii and poor in copepod fed larvae. Final total length (TL) of larvae fed prawn diet was higher than those fed copepod or nematodes. However, best growth was noted in larvae fed Artemia nauplii (TL= 24.30 ± 0.81 mm; BW = 156 ± 8 mg; specific growth rate or SGR = 5.33 ± 0.19%/d).
  • Conference paper

    Larval rearing of silver therapon (Leiopotherapon plumbeus) in outdoor tanks 

    FA Aya, VSN Nillasca, MNC Corpuz & LMB Garcia - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Silver therapon (Leiopotherapon plumbeus, Kner 1864), locally known as ayungin, is an important freshwater food fish species found in Laguna de Bay, the largest lake in the Philippines. Its market price is twice that of other most sought after freshwater fishes such as tilapia and milkfish. However, intense fishing pressure on the species has significantly reduced the wild stock in Laguna de Bay. Studies to develop hatchery techniques for this indigenous freshwater fish species are therefore needed to produce seedstock for possible culture and wild stock rehabilitation.

    This study highlights the successful larval rearing of silver therapon in outdoor concrete tanks. Larvae reared in outdoor tanks with natural food (grown two weeks beforehand) reached the juvenile stage (40 days after hatching (DAH)), suggesting the presence of some suitable live food organisms in pre-conditioned rearing water. However, larval survival rates were low (11.58 ± 6.56% at stocking density of 0.9 larvae l-1), which is probably linked to the density of food items, particularly during the onset of exogenous feeding or due to high stocking density of larvae. To improve the availability of natural food for the larvae, fertilization of the rearing water in the outdoor tanks stocked with larvae at two densities (0.4 and 0.6 larvae l-1) was performed. Larval growth and survival were improved at stocking density of 0.4 larvae l-1 than at 0.6 larvae l-1. Diet composition of first-feeding silver therapon larvae in outdoor tanks inoculated with cultured microalgae (Chorella sorokiniana) and zooplankton was also determined. Larvae were able to consume rotifers and some phytoplankton beginning at 2 DAH and larger preys such as cladocerans and insect larvae starting at 12 DAH.

    The efficacy of raising silver therapon larvae in outdoor tanks using ambient lake water was also evaluated. Larvae reared in ambient lake water grew well but survival (48.44 ± 7.85%) was significantly improved in treatments where tropical almond or talisay Terminalia catappa leaves were added during the first two weeks of larval rearing.
  • Conference paper

    Responsible shrimp culture through ecological approach 

    EA Tendencia - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Aquaculture is the fastest food-producing sector. It is the farming of aquatic organisms, like crustaceans, fish, molluscs and plants. Culture of aquatic organisms, particularly shrimps, is usually done in earthen ponds with some intervention in the rearing process to enhance production. Some of these processes to increase production are pond preparation, regular stocking, feeding, and the use of probiotics and other chemicals to improve soil, water quality, shrimp growth and immunity against diseases. The long range effect of the use of probiotics and other chemicals on the environment and on shrimps is unknown. Despite the various inputs, diseases continue to plague the industry, which could be due to the deteriorating environmental conditions that cause stress in shrimps thus making them susceptible to infection. Furthermore, chemicals and nutrients from aquaculture may affect biodiversity of the receiving environment.

    Responsible aquaculture is a sustainable development approach that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. There should be a good balance between satisfying human needs while maintaining or enhancing the quality of the environment and conserving natural resources. Human health or food safety as well as economic efficiency and/or livelihood opportunities should be taken into consideration. Responsible shrimp culture through ecological approaches to improve environmental conditions is herewith described.

    Ecological approaches recognize the interactions between an aquaculture farm and the external environment, including environmental resources and local communities. Ecological approaches to improve environmental conditions identified from cross sectional, longitudinal and tank studies may be classified into culture systems and phases of pond production: pond preparation and rearing. Two culture systems are identified to improve water quality: 1) the use of the greenwater system, and 2) the presence of mangrove in the receiving environment. Among the pond preparation practices, sludge removal, crack drying of pond, and liming were identified. Toxic substances as well as organic matter, which provide nutrients necessary for the growth of microorganisms, are removed during sludge removal and crack drying of the pond sediment. Liming to pH 11 kills most harmful microorganisms including the white spot syndrome virus; it also kills unwanted species in the shrimp pond like fish and crabs. During the rearing phase, abundant supply of natural food, low stocking density, less input, addition of fermented Avicennia alba leaves, use of molasses and rest periods are some of the important farming practices that reduce risk of disease occurrence. Other reported practices are crop rotation, biofloc technology, aquaponics, and integrated multi trophic aquaculture.
  • Conference paper

    Growth and survival of nile tilapia (Oreochromis niloticus) juveniles fed diets with varying levels of irradiated chitosan 

    K Gonzales, MN Corpuz & MRR Romana-Eguia - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Chitin is a natural biopolymer and the second most abundant after cellulose. Chitosan, a derivative of chitin which is soluble in acidic aqueous media, is used in many applications like food, cosmetics, biomedical and pharmaceutical products. It is used in agriculture for enhancing growth in crops while in aquaculture, chitosan is believed to improve the immune response of fish to stress-inducing agents, thus enhancing survival and possibly growth. This preliminary study was conducted to investigate the effects of various concentrations of irradiated chitosan on the growth performance of Nile tilapia, O. niloticus. Fish was fed with a control diet and three formulated diets containing increasing levels of irradiated chitosan (10g, 20g and 50g kg-1). Juvenile O. niloticus was fed once daily for 21 days. The ration was based on 5% of the fish biomass. Tilapia fingerlings (n=30 per tank) of uniform size were randomly distributed in four experimental groups each with three replicates following a completely randomized design. Growth and food utilization parameters were measured. Specific growth rate (SGR), mean weight gain (MWG), mean length increment (MLI) and feed conversion ratio (FCR) were computed and analyzed using ANCOVA. Results from the feeding trials showed no significant difference (P>0.05) in the different performance parameters under the different fish feed treatments. MWG, MLG, SGR and FCR varied in the stocks fed different fish feed treatments but with no significant differences. The results also showed 45-62% survival ratio. These suggest that although there is no significant difference between treatments and control, irradiated chitosan-supplemented diets do not retard the growth of O. niloticus. Chitosan should be studied further to determine how it can improve the growth performance, feed utilization and immune response of Nile tilapia.
  • Conference paper

    Resource assessment of sea cucumber in northern Iloilo, central Philippines 

    PA Alpasan & RA Billones - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
    A resource assessment of sea cucumber was conducted in six out of eight coastal towns in northern Iloilo, a fisheries rich area facing the Visayan Sea in the central Philippines. A yearlong assessment was conducted in 2012. Fishery dependent survey was done with the use of survey questionnaire translated into dialect. Six trained enumerators administered the questionnaires to 114 gatherers and 18 local traders. Fishery independent survey involving Belt Transect Method (BTM) for intertidal areas and Timed-Search Method (TSM) for subtidal areas were conducted in 21 GPS (Global Positioning System)-referenced sampling stations. Sample specimens were also collected and prepared for taxonomic identification. External morphology, internal structures (dissected samples) and spicule analysis were used in the identification.

    Fishery dependent survey showed that gleaning (40%) is the most dominant extraction method used. Various methods were also employed including the dangerous compressor diving and the destructive karas, a method using a rake-like device to scrape the sea bed. In terms of volume, the most heavily exploited sea cucumber belongs to the Stichopus groups. The trade of sea cucumber is dominated by island-based traders. Almost half of the traders are women, signifying that trading is a woman's domain as well. Derived monthly income from sea cucumber trade ranges from PhP 2,000-3,000 for gatherers and PhP 2,000-5,000 for the traders.

    Fishery independent survey resulted in the identification of six sea cucumber genera (Bohadschia, Holothuria, Paracaudina, Pseudocholochirus and Stichopus). Of the 32 species found belonging to the six genera, only 16 were identified up to the species level. Samples of unidentified specimen were sent to the University of the Philippines - Marine Science Institute (UP MSI) laboratory for molecular taxonomic identification. In terms of species count, the most dominant genera is the Holothuria with nine identified and seven unidentified species. H. impatiens is also the most dominant sea cucumber found in the area. Further, the recorded catch per unit effort (CPUE) for fishery-independent survey is 3-4 pcs/diver/hr.

    The resource assessment showed that the trade of sea cucumber is dictated by economic value rather than by ecological abundance. While the scale and extent of sea cucumber fishery in northern Iloilo is small-scale and island based, the study highlights the need for trade regulation and stock enhancement of heavily exploited species as extraction affects the ecological distribution of sea cucumber stocks in the area.

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