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  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) 

  Romana-Eguia, Maria Rowena R.; Parado-Estepa, Fe D.; Salayo, Nerissa D.; Lebata-Ramos, Ma. Junemie Hazel (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015-08)

  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.
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  Shrimp metabolism: The roles of lactate dehydrogenase (c31), glycogen phosphorylase (c34) and protein kinase (PK) as revealed by RNA interference 

  Tare, Maria Violeta R.; Kondo, Hidehiro; Hirono, Ikuo; Maningas, Mary Beth B. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Energy metabolism is well-studied in vertebrate systems, providing insights on the genes and mechanisms involved in different pathways necessary for the survival of an organism. Yet, such studies are still lacking in invertebrate systems much more in shrimp. An earlier study has showed several contigs from the black tiger shrimp to be homologous to white spot syndrome virus (WSSV), a devastating pathogen in shrimp, including contig 31-WSSVORF82 (c31) and contig 34-WSSVORF21 (c34). This study aims to unveil the roles of three genes: c31, c34 and protein kinase (PK) in the shrimp system and its possible role in WSSV-infection. Rapid amplification of cDNA ends-polymerase chain reaction or RACE-PCR was used to obtain the full-length sequence of c31 and c34, followed by in vivo gene silencing using RNAi technology, and intramuscularly injecting dsRNA to WSSVchallenged Macrobrachium rosenbergii and Penaeus (Marsupenaeus) japonicus. Gene expression followed for healthy shrimps and dsRNA-treated shrimps. Mrc31 was revealed to be the enzyme lactase dehydrogenase (LDH), commonly released during tissue damage and is a marker for disease. The most parsimonious tree pictured Mrc31 to be sister clades to LDH of other shrimp species, Penaeus monodon and P. vannamei, supported with 100% and 72% bootstrap values, respectively. Mrc34 was highly homologous to the glycogen phosphorylase (GP) enzymes of other organisms including that of another shrimp, M. japonicus, bearing a bootstrap value of 99%. For PK, phylogenetic analysis revealed that the three open reading frames (ORFs) from P. monodon, M. rosenbergii and P. japonicus have 30% homology to WSSV-PK supported by a 98% bootstrap value. Mortality data from dsRNA-treated and WSSV-infected shrimps showed that treatment with dsRNA-LDH, GP and PK had significantly higher survival rates compared to that of the controls, Phosphate Buffered Saline (PBS) and Green Fluorescent Protein (GFP). Silencing the three genes in the shrimp has rendered some protective effect against the virus. Gene expression showed that all three genes are present in immune-related organs such as the gills, hepatopancreas and hemocyte. This study is the first to report the possible identities and functions of contigs 31, 34 and PK providing valuable data on the shrimp's genome.
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  Reproductive biology of christian crabs (Charybdis feriatus, Linnaeus, 1758) in San Miguel Bay, Philippines 

  Nieves, Plutomeo M.; Olfindo, Nelson R.; Macale, Aldrin Mel (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  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.
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  First record of Laem-Singh virus in black tiger shrimp (Penaeus monodon) in the Philippines 

  Cruz, Christian Albert M.; dela Cruz, Precious C.; Alcala, Paul Christian D.; Tagle, Florenz Giovanni M.; Santos, Erickson S.; Santos, Mudjekeewis D.; Maningas, Mary Beth B. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Laem-Singh Virus (LSNV), a single-stranded RNA virus that causes growth retardation in Penaeus monodon, is also known as Monodon Slow-Growth Syndrome (MSGS) virus. Black Tiger shrimps afflicted with this virus exhibit unusual dark color, a weight gain of less than 0.1 g in 1 to 2 weeks, unusual yellow markings, bamboo-shaped abdominal markings and brittle antennae. It was first detected in Thailand and the virus quickly spread to neighboring Asian countries such as Malaysia and Singapore. The shrimp economy of countries where infections have occurred experienced losses in the export of live shrimps and broodstocks. An earlier study in 2009 reported that LSNV was not present in the Philippines. However, since no follow-up researches were done in the succeeding years, this study was conducted to detect the presence of virus in selected sites of Luzon. Results based on biased sampling method and RT-PCR data indicated that LSNV is indeed present in the country. This is further supported by DNA sequence data, showing 100% identity with LSNV India isolate. Phylogenetic analysis showed that the Philippine isolate clustered closely with other LSNV isolates. The outcome of this study might have implications in the current practices in the Philippine shrimp aquaculture industry.
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  Growth performance of brackishwater enhanced selected tilapia (BEST) reared in brackishwater ponds 

  Labastida, Anecito V.; Jumawan, Celestina Q.; Abogado, Antonio A.; Palma, Rheino B.; Sabillo, Jerome J. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Tilapia culture contributes greatly to world aquaculture production. Several tilapia strains have been developed locally and one of these has been developed for brackishwater aquaculture. BEST or the Brackishwater Enhanced Selected Tilapia was developed by the Bureau of Fisheries and Aquatic Resources with the aim of promoting brackishwater culture of this commodity to further improve tilapia production in the Philippines. This study will determine the growth performance of BEST reared in organically fertilized brackishwater ponds at three different stocking densities. The study was conducted in nine (9) units of 200m2 ponds. Pond preparation was done following standard procedures that include drying, liming, teaseed application and fertilization. Stocking was done after twenty days when primary productivity in the ponds was noted. Three culture systems were used, namely: extensive (Treatment 1 or T1), semiintensive (Treatment 2 or T2) and intensive (Treatment 3 or T3) systems. The study was conducted for 120 days. Results showed that fish in ponds in treatment T1 had an average body weight (ABW) of 52.1g, T2 stocks with ABW of 223.1 g and T3 stocks with an ABW of 214.5 g. Meanwhile, T1 stocks had a survival rate of 91.9% while stocks under T2 and T3 had survival rates of 80 % and 84% respectively. T1 results showed losses amounting to P382 since total revenue of P958 is smaller than total cost of P1,340. T2 harvest on the other hand registered a total revenue of P 10,368 and total cost of P 4,375 hence net return of P 5,634. T3 also had total revenue of P 21,419 with a total cost of over P 8,498 giving a net return of P12, 471. T2 showed a return on investment (ROI) of 128% and a payback period of 0.77 year. T3 had an ROI of 139% and payback period of 0.71 year. Average feed conversion ratio (FCR) in two runs for two treatments are the same at 1.1 Water parameters like DO, salinity, temperature; water level and pH were also taken. Water level in the ponds ranged from 70 to 74 cm, salinity at 6.3-6.9 ppt, DO at 1.5-1.7ppm, temperature at a constant 29°C, monthly pH ranges were from 7.1 to 8.0 and transparency of 34-47 cm.
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  Distribution and abundance of hard clam shells Meretrix meretrix along the coastal areas of Panguil bay, Lanao del Norte, Philippines 

  Jumawan, Celestina Q.; Palma, Rheino B.; Sia, Renalyn O. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Meretrix meretrix is believed to be abundant in Panguil Bay and in the absence of relevant fishery statistics, it is useful to quantify their biomass with a view to determining their fishery potential. This study aims to monitor the gonadal development, identify the associated macrofauna and determine the distribution and abundance of hard clam shells M. meretrix along the coastline of four municipalities of Lanao del Norte at Panguil Bay. Four sampling sites were selected and established to achieve and relate some generalities using the transect-quadrat method. Clams were counted, measured and identified. Physicochemical parameters were also noted every sampling. M. meretrix was found to be most abundant in Raw-an Pt. Baroy (28-542 pcs./m2) followed by Mayao, Lala (0.3-26 pcs/m2). M. meretrix at Aloha Tubod occurred in low densities (0.1-4 pcs/m2). No hard clam shell was found in Taguitic, Kapatagan. Mean length differed significantly at the three locations. The coastal area of Mayao, Lala, had the highest diversity (H' = 4.236737) in terms of shell species identified and recorded during the twelve months sampling period. Most of the shells dissected were sexually immature with male shellfishes being more predominant than females. Differences in distribution, density and length size of hard clam shells were compared in this study at four locations. Anthropogenic causes e.g. exploitation as well as environmental parameters such as salinity levels and sediment quality are suggested to be the main cause of the variation. These results will be used as baseline information to properly manage hard clam shell resources in Panguil Bay.
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  Preliminary trials on the optimization of hormone dosages for induced breeding of Philippine silver perch, Leiopotherapon plumbeus 

  Javier, Mark Archei O.; Aya, Frolan ; Romana-Eguia, Maria Rowena R. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  The silver perch Leiopotherapon plumbeus, locally known as ayungin, is an endemic freshwater fish that is commercially valuable as it commands a high price in the local market. Due to excessive fishing and other potential causes such as predation by invasive alien species, the local L. plumbeus stocks are observed to be depleting hence there is a need for an induced breeding protocol to propagate silver perch and conserve what remains of the resource. In this study, 30 females (total length or TL: 109.4 ± 12.2 mm; total body weight or TBW: 20.3 ± 6.1 g) and 60 males (TL: 97.1 ± 11.6 mm; TBW: 13.4 ± 5.5 g) were injected once intra-muscularly with different doses of hormones. Various dosages of human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analog (LHRHa) and salmon gonadotropin releasing hormone (sGnRH) were evaluated to identify the most effective dosage and hormone that resulted to high ovulation, fertilization and hatching rate. For the hormone sGnRH, 20, 30 and 40 µg/kg body weight (BW) and 1, 2 and 3 µg/kg BW for LHRHa were the dosages used in the experiment. The dosage used for HCG is 50 IU/g BW and served as the control. The findings of the experiment determined that the use of 20 µg/kg body weight of sGnRH resulted to high ovulation, fertilization and hatching rates. The result of the experiment would provide an efficient protocol for the local fishermen so they can produce, on demand, a large supply of this high quality fish species.
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  Perceptions on the effects of maritime activities on the Philippine aquatic ecosystem 

  Java, Enrique; Cruz, Teresita; Hernandez, Isidro Yonggue (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

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

  Gonzales, Kristine; Corpuz, Mark Nell; Romana-Eguia, Maria Rowena R. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  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.
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  Modelling the impact of different stress agents on Holothurian immunity 

  Dolmatova, Liudmila S. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Due to dietetic and pharmacological values of many species of sea cucumbers (Holothuroidea, Echinodermata), and depletion of their natural resources, the species of little or no commercial value attract attention as new raw material resource, and methods of their aquaculture are developed. Both monitoring and supporting the health of animals in natural and artificial conditions demand the approaches providing reliable markers. This study compared the influence of two stress agents, namely lead and bacterial toxin Yersinia pseudotuberculosis (ТсТYp), on some of the markers of immune response of the Far Eastern holothurian Eupentacta fraudatrix. Phagocytes (P2 type) were isolated after 48h treatment of holothurians E. fraudatrix with Pb(NO₃)₂ (2 and 4 mg/L). In another experiment, coelomocyte were incubated with ТсТYp (0.2 and 0.5 µg/g) for 18h. Apoptosis level and FITC-conjugated concanavalin A (con A) and binding of lectins from Glycin Max and Dolichos biflorus to P2 surface receptors, and activity of antioxidant enzymes were measured. Lead induced an increase in catalase and decreases in superoxide dismutase and glutathione-S-transferase and glutathione reductase activities at dose of 2 but not 4 mg/L. 2 mg/L lead also increased apoptosis level. Noteworthy, receptors to lectins from G. Max and D. biflorus were poorly expressed in the control, and significantly expressed under lead treatment at a dose of 2 but not 4 mg/L (D. biflorus) or decreased at a dose of 2 but not 4 mg/L (G. Max). Binding con A was significant in the control and additionally increased under treatment with 2, but not 4 mg/L. Meanwhile, ТсТYp also induced reversed concentration-dependent effect on apoptosis: 48h incubation with 0.5 µg/g decreased apoptosis, and 0.2 µg/g-increased it. Additionally, 0.2 µg/g ТсТYp decreased binding con A and D. biflorus lectin. Commercially available catalase restored % lectin binding to the control level. Data obtained indicate that lead and ТсТYp differently influenced phagocyte activity, and complex definition of apoptosis level and activity of antioxidant enzymes. Finally, variations in expression of cell surface receptors may be useful for estimation of the level of stress damage to holothurians.
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  Preliminary assessment of the abundance and fishery of snapping shrimp (Alpheus sp.) in Calape, Bohol, Philippines 

  Baobao, Jomel G.; Rabia, Maria Danesa S.; Rulida, Ernesto C. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Snapping shrimp Alpheus sp. is abundant in Calape, Bohol, particularly in coastal areas with a wide intertidal zone, mangroves and rich mud banks. Locally known as takla , it is considered as one of the major seafood delicacies in the municipality. An initial assessment of the natural population and fishery of the snapping shrimp was conducted. Using quadrat sampling, mean density was noted at 7 individuals m-2, body weight ranging from 3.87-12.86 g and total length at 4.78-7.44 cm. The largest individual was identified as male having larger claws, the size being two times larger than that found in females. Apart from actual field sampling, a total of 80 shrimp gatherers were surveyed to obtain relevant fishery information for the snapping shrimp. The snapping shrimp is sold in the local public market and traded in hotels and seafood restaurants at PhP50.00 bundle-1 (a bundle averaging 20 pieces) and PhP180.00 a kilo. The current average catch per gatherer is at 75 pieces on a daily basis which is relatively lower compared to the average catch in the 1980s and 1990s ranging from 150-300 pieces day-1. Destruction of mangrove swamps due to fishpond conversion, unabated mangrove cutting for commercial firewood production and unrestricted gathering of snapping shrimps were identified as possible causes for the decline. These baseline data are essential for the local government and the community to come up with appropriate protection and conservation measures. An intensive and comprehensive study on the snapping shrimps ecology and biology also need to be conducted to provide basis for sound and holistic management of this valuable resource.
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  A preliminary study on the diagnosis of coral reef healthiness and establishment of coral replenishment technology 

  Azuma, Teruo; Tan, Jemar Jed Roble; Zarate, Jacques; Altamirano, Jon; Gatus, Joey; Sotto, Filipina (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

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

  Aya, Frolan ; Nillasca, Vicar Stella N.; Garcia, Luis Maria (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

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

  Aya, Frolan ; Nillasca, Vicar Stella N.; Corpuz, Mark Nell C.; Garcia, Luis Maria (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  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.
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  Development of a simple, rapid, cost-effective diagnostic kit for WSSV 

  Arabit, Pocholo Mari T.; Nicolasora, Amalea Dulcene D.; Go, Patrick Ellis Z.; Caipang, Christopher Marlowe A.; Maningas, Mary Beth B. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Shrimp aquaculture is one of the most important sources of income and livelihood in the Philippines. For the past two decades, the white spot syndrome virus (WSSV) has adversely affected the production of the Philippine shrimp industry resulting to losses in revenue. Shrimps infected by the virus experience up to 100% mortality, 3 to 10 days post-infection. One way of controlling the disease is early detection, which remains to be too complicated and inaccessible to shrimp farmers. Being a DNA virus, the first step to WSSV diagnosis is the isolation of high-quality DNA suitable for polymerase chain reaction (PCR) or loop-mediated isothermal amplification (LAMP). Using readily available and affordable reagents, a DNA extraction protocol has been especially developed for rapid WSSV-detection; DNA has been successfully extracted from the pleopods of shrimps and the results were comparable with that of commercially available kits from Promega and Zymoresearch. LAMP has been optimized for WSSV detection in the temperature range of 55°C to 68°C and was shown to be faster and ten times more sensitive than conventional PCR. This study together with a locally fabricated machine, offers a more convenient, practical and efficient way of detecting WSSV, with the advantage of using non-invasive means of obtaining shrimp tissue therefore not losing any shrimp meat in the process.
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  Optimization of feeding and growth conditions for hatchery-bred larvae of indigenous Philippine silver perch, Leiopotherapon plumbeus (Perciformes: Terapontidae) 

  Añano, Julie Andrea; Aya, Frolan ; Corpuz, Mark Nell; Romana-Eguia, Maria Rowena R. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  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.
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  Resource assessment of sea cucumber in northern Iloilo, central Philippines 

  Alpasan, Perry A.; Billones, Romy A. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  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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  Stock enhancement? Why bother 

  Ingles, Jose (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  There are two approaches to resource enhancement of depleted wild fish stocks: through stock enhancement where aquaculture science plays a central role, or through improved management of fish stocks. This paper presents an argument that despite major advances in stock enhancement technologies (tagging, genetic mapping, numerical modeling techniques), major hurdles in policy framework, science and information gaps, risk mitigation protocols and capacity gap remain. These factors are associated with high and recurring cost that requires medium to long-term solutions that ultimately, improving management and governance to recover depleted stocks will still be the best option available.
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  The importance of mangroves to capture and culture fisheries 

  Primavera, Jurgenne (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  Abstract only.
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  Good aquaculture practices (GAqP): setting directions for harmonized regional standards - the Philippine experience 

  Matubang, Mark F.; Lopez, Nelson A. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2015)

  A milestone process on how Good Aquaculture Practices (GAqP) emanates in Philippine aquaculture and its integration to the ASEAN harmonized standardization efforts is discussed in the paper. The management model, value chain and draft Philippine National Standard of the GAqP code are presented and evaluated as to its impact to trade and marketing, socioeconomic considerations, food safety and technology.

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