Recent Submissions

  • Conference paper

    Mangrove structure and mud crab population in northern Samar 

    ET Quinitio, EB Vista, RC Vista & MJH Lebata-Ramos - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    This study assessed the mangrove community structure, relative seasonal abundance of all size classes of crabs (catch per unit effort or CPUE) and percent composition of the catch in two collection grounds in Pambujan and Rosario, Northern Samar using cylindrical bamboo traps and lift nets. Mangroves in Pambujan was dominated by Avicennia marina and A. alba. The initial total count of mangrove trees (67 stems ha-1) was slightly higher compared with the final count (61 stems ha-1). On the other hand, mangroves in Rosario was dominated by Rhizophora apiculata and R. stylosa. The total count of mangrove trees was higher in the initial (108 stems ha-1) compared with the final (46 stems ha-1). However, saplings and seedlings increased in both sites after 18 months. Mean CPUE ranged from 0.04 to 0.4 crabs using cylindrical bamboo traps in the monthly spring tide sampling for 19 months in Pambujan. High mean CPUE was recorded in February and August 2008. Mean CPUE ranged from 0.04 to 0.41 crabs using lift nets in the monthly spring tide sampling. The highest mean CPUE was noted in August. The initial and final CPUE were comparable. In Rosario, mean CPUE ranged from 0.3 to 1.78 crabs monthly caught in cylindrical bamboo traps and from 0.04 to 0.77 crabs in lift nets. In general, the number of crabs caught in both traps was higher in Rosario than in Pambujan. Mud crab ranged from 2.02-72.2% of the monthly total catch in lift nets in Pambujan. Other species of crabs ranging from 27.78 to 86.36% were the dominant catch in several months. In Rosario, mud crab ranged from 12.5 to 82.35% of the monthly total catch. The catch composition of the cylindrical bamboo traps was more varied compared with lift nets in both sites. The decrease in the population of mud crabs may also be associated with the decrease in mangrove trees. With the continuous cutting of trees and regular extraction of all sizes of mud crabs, the industry may no longer become sustainable. This paper is the first to be done on the assessment of the mud crab population in Northern Samar and the information gathered can be used as basis for the development and improvement of the existing fisheries legislation for the conservation and management of the remaining wild resources.
  • Conference paper

    Pilot scale production of pellets suitable for mud crab Scylla serrata 

    RM Coloso, MR Catacutan, JP Peralta, JG Genodepa, K Duno & R Gardoce - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Studies were conducted towards the pilot scale production of stable and nutritionally adequate pellets suitable for mud crab Scylla serrata to help in efforts to increase mud crab production in the Philippines. Preliminary studies showed that mud crabs preferred pellets which were spherical or cylindrical and contained marine based attractants. Two practical diets were formulated and prepared in the Pilot Feed Mill of SEAFDEC/AQD. The extruded diets, along with a commercial mud crab grow-out diet, were subjected to proximate and Ca/P analyses as well as cholesterol analysis and water stability tests. The diets were fed to crabs in a controlled laboratory experiment using fiberglass tanks with flow-through, aerated seawater, and monitored from initial molt (M0) up to the second molt (M2). Tests revealed that the crabs fed Diet 1 (CP 48.28 %, CF 7.74 %, Ca 5.23%, P 12.93 %, cholesterol 0.173 %) showed the highest growth and better survival than those fed Diet 2 or commercial diet. Crabs fed Diet 1 took a shorter time to attain two molt cycles from M0. Survival was 70% after M2. Diet 1 was water stable within two hours. Abnormalities were observed including absent swimming legs or chelae, exposed gills, sores on exoskeleton, incomplete molting, or soft exoskeleton, but none that could be directly attributed to a specific treatment. Incomplete molting and slow hardening of the exoskeleton in crabs that accounted for the mortalities could be due to the low cholesterol levels in the diets especially in the commercial diet which had the lowest cholesterol level. Cholesterol supplementation of the artificial diet would be needed to improve molting success and survival of mud crabs in grow-out culture. The results of these experiments will be used to formulate a cost-effective grow-out diet for mud crab (supported by DOST-PCAARRD Grant in Aid).
  • Conference paper

    Nursery and grow-out feeding management of mud crab farmers in the Philippines: Santeh experience 

    JRA Gabiota - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Mud crab (Scylla serrata) farming has been one of the means of livelihood of many Filipino farmers in coastal areas, specifically in Southern Luzon and Visayas. Nursery and grow-out operations in these areas vary in terms of their feeding management and techniques for a better yield. Farmers in Bicol region, specifically Sorsogon which is one of the sources of wild crablets in the country, are presently using pelleted feeds for nursing different crab sizes. On the other hand, farmers in Quezon, Bataan, Masbate, Negros and Capiz are growing crabs to marketable size for domestic and export markets.

    It was noted that there are still farmers in some areas that use low value fish for feeding crabs resulting in the deterioration of the pond bottom and water environment. On the other hand, pelleted feeds serve as an alternative feed that addresses the problem of the declining supply of trash fish, corn, mussel and snails. The price of trash fish has increased significantly due to its unavailability in several areas. In addition, pollution of the water environment and fluctuations in the water parameters for crabs due to improper pond preparation, pollution and climate change have added stress to the crabs.
  • Conference paper

    Biological evaluation of existing feed formulations for the grow-out culture of the mud crab, Scylla serrata 

    MR Catacutan - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    This study was conducted to identify a formulated pelleted feed for the grow-out culture of the mud crab. A commercial crab feed (CCF) was evaluated together with fish by-catch (FBC) and three test diets (formulated and pelleted) of similar dietary energy (1723 MJ/Kg diet) based on published works. The test diets contained 48% (D-1), 43% (D-2), and 38% (D-3) crude protein (CP), respectively. All the five dietary treatments were fed to crablets (5 to 6 g body weight) that were individually stocked in 60-L tanks. Each dietary treatment was fed to six crabs. Crustaceans grow by molting which is not simultaneous, hence, each crab was monitored daily. After the third molt (M3) survival rates in D-1, D-2 and D-3 ranged from 33%-66% compared with only 16% in FBC, and 0% in CCF where no crab survived to molt for the second time (M2). Nutrients in FBC may not be sufficient to sustain growth and survival, while water stable CCF may lack a feed attractant. Diets D-1, D-2, and D-3 were evaluated in another feeding experiment to identify the basal diet for the crab. All crabs molted until M3 and no significant differences were noted on growth performance between treatments. However, D-1 (48% CP) was identified as the basal diet due to better numerical values observed in terms of feed conversion ratios and specific growth rates.
  • Conference paper

    Recent developments and enhancing transfer of the nursery technology for the mud crab Scylla serrata 

    FD Parado-Estepa, V Alava, E Garibay, C Bejemino, J Sumile, J Silvestre & ET Quinitio - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The development of hatchery techniques for seed production of mud crab is expected to address the present problem on the depletion of wild seedstock supply for stocking in grow-out ponds. The nursery serves as the link between the two phases of culture as this involves growing of juvenile crabs produced in the hatchery to sizes that are suitable for stocking in the ponds.

    Nursery rearing involves the use of net cages installed in ponds as holding system for ease in harvest and retrieval of crabs. In the first nursery phase, 0.3-0.5 cm carapace width (CW) juvenile crabs are reared to 1.5-2.0 cm CW for 3-4 weeks and stocks are harvested for selling or are grown further in a second nursery phase in which crabs reach 2.5-3.0 cm after another 3-4 weeks. This paper includes a review of techniques initially developed for the nursery and more recent refinements which involve the use of higher crab instar densities, provision of suitable shelters, trimming of claws and sorting. In addition, production results in farms of collaborators are presented to highlight the efficiency of dissemination and also discusses the challenges faced by the potential nursery industry.
  • Conference paper

    Philippine National Standard for Live Mud Crabs: establishing food safety and quality requirements 

    MF Matubang, TS Palomares, JP Peralta, ET Quinitio, RJ Ragaza, JV Alejo, PB Regazpi, CE Romero, HA Montoya, JG Trinidad & KKA Roscom - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The Bureau of Agriculture and Fisheries Standards (BAFS) of the Department of Agriculture (DA), in collaboration with the relevant government and research agencies, academe and industry organization, is currently developing the Philippine National Standard (PNS) for live mangrove crabs (also known as mud crabs). This PNS defines the food safety and quality requirements for live mangrove crabs in order to ensure consumers’ health and make the product globally competitive. The process in the development of standards include review of the existing requirements of local and foreign markets and internationally recognized standards, creation of the Technical Working Group, initial drafting of the PNS, conduct of public consultations in major production areas, finalization of the draft for the PNS, notification to the World Trade Organization and approval of the DA Secretary.

    The PNS for live mangrove crabs specifies the scope of the standard, product description, essential composition and quality factors, hygiene, handling, labeling requirements, methods of sampling, examination and analysis, definition of defectives, and the requirements for product lot acceptance.
  • Conference paper

    Genetic diversity and stock delineation of Philippine populations of the orange mud crab, Scylla olivacea 

    FJM Paran & RJ Ravago-Gotanco - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The orange mud crab, Scylla olivacea, is regarded as an important fishery resource due to high demand and high market value. However, mud crab populations are threatened by over exploitation and habitat degradation, and would benefit from resource management interventions. The study examined patterns of genetic diversity and connectivity of orange mud crab populations across the Philippines, with the aim of identifying putative management units. A total of 387 Scylla olivacea were collected from ten localities across the Philippine archipelago. Phylogenetic analysis of mitochondrial control region (mtDNA-CR) DNA sequences revealed cryptic diversity among Scylla olivacea specimens with four mitochondrial lineages recovered. Analysis of molecular variance revealed that Philippine populations do not constitute a single genetic stock (0ST=0.00262; P=0.00015). Thirteen microsatellite loci were also utilized as additional markers to infer population structure and estimate genetic variation. Overall, S. olivacea populations exhibit high haplotype diversity (mean h=0.9803) and nucleotide diversity (mean ~p3.46%), which may be indicative of a large, stable population within Philippine archipelagic waters. This study provides information on genetic diversity and population structure of S. olivacea, which will be useful towards developing management and conservation strategies for sustainable development of natural S. olivacea populations in the Philippines.
  • Conference paper

    Identification of mud crab species in coastal areas of Pangasinan 

    RB Cerezo & MC Tapia - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The study was conducted to identify the mud crab species (Scylla spp.) that thrive in 12 coastal municipalities and 2 cities in Pangasinan. Ten mud crab samples were taken from each of the sampling site and classified based on Keenan et al. (1998). Likewise, the abundance and differences in size and weight of the mud crab samples were determined. The study showed that there are only three mud crab species, Scylla serrata, S. tranquebarica and S. olivacea, found in the coastal areas of Pangasinan. S. serrata was the most abundant species (54.28%), followed by S. tranquebarica (24.28%) and S. olivacea (22.14%). Crabs weighing more than 300 g (~.12 cm carapace width or CW) were obtained from the municipalities of Anda, Bolinao, Dasol, Burgos, Bani, Agno, Alaminos and Infanta. These municipalities are geographically situated in coastal areas where S. serrata are found. Crabs weighing below 300 g (~.12 cm CW) were collected from the municipalities of Sual, Labrador, San Fabian, Lingayen, Dagupan and Binmaley. These towns have mangrove areas and low saline waters where S. tranquebarica and S. olivacea thrive.
  • Conference paper

    Breeding and culture of the polychaete, Marphysa mossambica, as feed for the mud crab 

    VR Alava, JB Biñas & MAE Mandario - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Marine worms (Annelida: Polychaeta) are considered as important food for crustacean broodstock because they contain hormones and correct balance of essential nutrients for reproduction. Marphysa mossambica (Peters, 1854) occurs in muddy coastal areas and is abundant in fish farms where it builds burrows in nutrient-rich sediments. This species encapsulates their eggs and larvae in gelatinous masses (jelly cocoons). It is a multiple spawner, and breeders are repeatedly spawning in tanks. Culture techniques have also been developed and established in tanks. Based on dry weight, cultured M. mossambica contained 62-66% crude protein and 7-12% lipids with levels of highly unsaturated fatty acids (HUFAs) such as arachidonic (20:4n-6), eicosapentaenoic (20:5n-3) and docosahexaenoic acid (22:6n-3) at 0.2-0.5%, 0.2-0.3% and 0.3-0.5%, respectively. Stocks were monitored for the presence of white spot syndrome virus (WSSV) using polymerase chain reaction-based diagnostic methods. The WSSV-free polychaetes mass-produced in tanks were utilized as live food for mud crab S. serrata broodstock. Mud crab broodstock fed natural food (mussel, fish, and squid) with live Marphysa on daily feed rotation produced higher number of crab zoeae, larval survival, total lipids and HUFAs than those fed natural food without live Marphysa. Production of nutrient-rich WSSV-free polychaetes in captivity can play a significant role in supporting crustacean hatcheries that supply seeds to the nursery and grow-out.
  • Conference paper

    Implication of mud crab culture technology transfer on rural coastal communities: The case in northern Samar, Philippines 

    DB Baticados, RF Agbayani & ET Quinitio - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    The socio-economic implications of technology transfer of mud crab culture on small-scale growers in Northern Samar and the mechanism of nursery technology transfer were investigated. The study covered four Peoples Organizations (POs), each operating in villages of the four municipalities of Northern Samar namely, Lavezares, Rosario, Laoang, and Pambujan. These were sites of the Philippine-Australian Community Assistance Program - assisted mud crab (Scylla) culture livelihood projects. Interviews from 60 beneficiaries revealed that most (76%) were relatively new to mud crab culture, particularly fattening or growout, but 65% were gleaners of mud crabs for more than 5 years. The average age of respondents was 45 years old and were predominantly male. Most (93%) were married with an average household size of six. A cost and return analysis of mud crab fattening in pens using only two compartments showed that the net income (P4,832/month for a 30-day culture period) is not sufficient if shared among 40 PO members participating in only one economic activity. Consequently, most (63 %) respondents whose livelihood projects were cooperative undertaking were no longer keen with the cooperative-run project. Interestingly, those (83 %) who operated their own farm wanted to continue and expand (26 %), particularly those in Rosario. The motivation factors that influenced growers to continue mud crab culture and adopt the nursery technology being disseminated were primarily economic with extra income and source of cash as main reasons for adoption. Majority also claimed that the nursery technology that was being transferred by SEAFDEC/AQD was simple.

    The mud crab pond nursery technology transfer involved community training and participation of beneficiaries, beginning with the linking of technologists and socio-economists with on-the-ground partners. Thereafter, season-long training and farm demonstration followed comprising lecture series and hands-on demonstration. Nursery pond operations were conducted in an open pond (Rosario) and in a pond within a mangrove area (Pambujan). Survival in the pond within a mangrove area was higher (68 %) than in an open pond (50 %) for phase 1, suggesting that the mangrove played a role on mud crab endurance. However, survival in phase 2 (72 %, Pambujan; 83 %, Rosario) showed a reversed trend, suggesting that bigger crablets can withstand/endure harsh pond conditions.

    Results of the demonstration indicated that the nursery technology is a viable enterprise, showing an ROI of 93.50% in Rosario and 198.04% in Pambujan. Most (83%) of the growers were interested in the nursery technology, although only few PO members participated in the season-long training. Ownership of area, market, and farm distance from household were the more important considerations that influenced small-scale growers in adopting the technology.
  • Conference paper

    Mud crab marketing practices 

    AG Decembrana - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Presented in the article is the mud crab (Scylla spp.) marketing practices in the province of Capiz. It is one of the major producers of mud crab in brackishwater ponds in the country. Hence, several trading centers or buying stations are found in this province. In Pontevedra, Capiz alone, there are more than 20 buying stations. The crabs from ponds coming from Aklan, Iloilo and within Capiz are brought to the buying stations almost daily. There are 5 kinds of market in the mud crab trading business such as, households, local markets/restaurants, traders/buying, exporters, and importers. Methods in classifying and packing of crabs are also discussed.
  • Conference paper

    Overview of the mud crab industry in the Philippines 

    ET Quinitio - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Mud crab farming has long been established in the Philippines and the country is the second top producer in the world. Except for Scylla paramamosain, the three other species, S. serrata, S. tranquebarica and S. olivacea are commonly found in the country, but S. serrata is the preferred species for farming. Crab seeds for farming are mainly from the wild and in recent years, a small percentage from the hatchery. Due to the apparent decline of the wild crab stocks, provincial and municipal ordinances have been issued by a number of Local Government Units (LGUs) along with the Bureau of Fisheries and Aquatic Resources (BFAR) to conserve and manage the remaining resources. From the hatchery, megalopa or crab instars are grown in net cages installed in the nursery pond. Mud crab farming engages mostly in long-term grow-out culture of juvenile crabs to market size for 3-5 months, short-term fattening of lean crabs for 15-45 days, and recently, soft-shell crab production. Polyculture of juvenile crabs to market size with one to three other commodities in earthen brackishwater ponds is usually practiced. Mud crabs for soft-shell crab production are mainly from the wild, while SEAFDEC/AQD demonstrates the use of hatchery-produced juvenile mud crabs as seedstock.

    Refinement is continuously being done to improve the economic viability of producing crabs, although basic technologies have been developed for all phases of culture (hatchery, nursery, grow-out, fattening and soft shell crab production). The major issues facing the industry are the lack of seedstock, difficulty of zoea 5 to molt to megalopa stage, cannibalism particularly at the nursery phase, species identification at the juvenile stage, use of fish as aquafeed, diseases, effects of climate change and quality of crabs at postharvest. In 2012, the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) of the Department of Science and Technology (DOST) started funding projects under the National Mud Crab Science and Technology Program (NMCSTP) to address these issues. The major aim of the Program was to improve the production, profitability and sustainability of crab farming. SEAFDEC/AQD leads in capacity building with focus on the sustainability of the mud crab industry. Various collaborations and research studies on mud crab culture enabled SEAFDEC/AQD to package mud crab technologies, conduct local and international training courses and on-site technology demonstrations, and publish extension manuals and scientific publications since the mid1990s. Research and Development activities have been translated into improved production. With the recent developments and refinements of technologies, it is expected that the Philippines will increase its production by 25-50% in the next 5 years.
  • Conference paper

    Unified provincial fisheries law enforcement of ordinance of Camarines Norte focusing on mud crab 

    EA Estanislao - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Due to overfishing and widespread coastal habitat degradation, the Province of Camarines Norte passed a provincial fisheries law enforcement known as the Unified Provincial Fisheries Law Enforcement Ordinance of Camarines Norte (UPFLEON) (P.O. 50-10). Given emphasis in the paper is the banning in the collection and possession of less than 1.0 cm juvenile crabs.
  • Conference paper

    Development of protocol for the production of hatchery-reared mud crab Scylla serrata juveniles for soft-shell crab farming 

    ET Quinitio, GX Libunao & FD Parado-Estepa - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Development of economically viable techniques for growing hatchery-reared juvenile crabs to suitable sizes will address the problem on the source of seed stocks for soft-shell crab farming. This paper reports the production of hatchery-reared mud crab Scylla serrata from juveniles in the nursery to 73-106 g body weight (BW) crabs in the grow-out pond for the individual system soft-shell crab farming. Likewise, the performance of hatchery-reared S. serrata, and wild S. tranquebarica and S. olivacea juveniles was determined in the soft-shell crab production set-up.

    The BW increased from 1.8-1.9 g to 78-113.7 g when stocked at 0.5 ind m-2 and from 1.6-2.3 g to 73-106.7 g at 1.0 ind m-2 after 75 days. Growth rates at both stocking densities were comparable. However, survival was significantly higher (P<0.05) in lower (63.6~c1.01%) than in higher (35.6~c3.34%) stocking density. Male S. serrata (46.0 ~c 1.75%) had significantly higher BW increase than females (39.4 ~c 2.05%). Crabs stocked at sizes of 51-60 g showed significantly greater percent increase in BW (43.26~c 0.98%) compared with those at 61-70 g (40.98~c1.33%), 71-80 g (38.55~c 1.04%), 81-90 g (36.34 ~c 1.27%) and 91-100 g (38.52 ~c 1.67%). Among the three species, hatchery-reared S. serrata (42.14 ~c 1.34%) had significantly higher mean percent BW increase compared with S. olivacea (38.23 ~c 0.49%) and S. tranquebarica (36.16 ~c 0.78%). S. serrata had significantly shorter mean culture period (24.11 ~c 0.95 days) than S. tranquebarica (28.48 ~c 0.54 days) and S. olivacea (28.75 ~c 0.34 days).
  • Conference paper

    Strategies to reduce disease incidence in mud crab culture 

    EC Amar, MD Somera, SB Madero, EA Tendencia & JP Faisan Jr. - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Mud crab hatchery suffers from low survival due to susceptibility to bacterial infection in the early larval stages among many causes. Despite food safety issues, antibiotics continue to be used in the absence of effective alternatives. In this study, screening of plant extracts was conducted to determine their suitability as antimicrobial agents against pathogens causing low survival in the hatchery. In addition, potential probionts were isolated from the gastrointestinal tract of mud crab, and water and sediments of mud crab grow-out ponds.

    Crude ethanolic extracts from various terrestrial and mangrove trees were tested for in vitro antimicrobial activity and toxicity to mud crab zoea and megalopa. In addition, the in vivo antimicrobial efficacies of the selected extracts were tested by oral administration followed by experimental challenge with Vibrio harveryi. On the other hand, the putative probionts, were tested for pathogenicity against mud crab zoea and megalopa and quorum sensing inhibition activity against V. harveyi. Finally the extracts and probionts were tested for their efficacy in simulated hatchery and grow-out trials.

    Results showed that extracts of Terminalia cattapa and the potential probiont Bacillus subtilis G100R11 showed antimicrobial and probiotic activity in in vitro and in vivo tests. In simulated hatchery trials, T. cattapa administration successfully produced crab instar with a survival of 1.3-1.8% in trials 1 and 2 comparable to antibiotic control. B. subtilis produced crab instar with survival of 0.8-1.0% in trials 1 and 2, better than the commercial probiotic with 0-0.13% survival. Using T. cattapa and B. subtilis, survival was above 30% until zoea 5 but suddenly dropped below 5% during metamorphosis to megalopa where high incidence of incomplete molting was observed. If difficulty affecting the molting process is addressed, high survival from zoea to megalopa and crab instar will be achievable.
  • Conference paper

    Enhancing mud crab population through mangrove restoration 

    MJH Lebata-Ramos, EF Doyola-Solis, RC Sibonga, JB Biñas, M Walton & L Le Vay - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Mangroves are known as important nurseries for different species of fish and shellfish. In the Philippines, mud crabs Scylla spp. are among the most valuable crustaceans harvested from the mangroves and are considered a delicacy. However, varying levels of overfishing have been reported in different parts of the country. The decrease in production may be due to increasing demand for the resource and the loss of mangrove habitat. This problem may be addressed through regulation of fishing effort, rehabilitation of habitats, mangrove-friendly aquaculture and enhancement of wild crab stocks. This study shows the effect of mangrove rehabilitation on mud crab population.

    From July 2010 to December 2011, a total of 2.166 tons of mud crabs (n=17,558) have been collected from a 66.5 ha abandoned pond that has been recolonized by mangroves. The catch was dominated by S. olivacea (79.96%), then S. tranquebarica (19.92%) and S. serrata (0.12%). Male to female ratio was at 1.09:1. Individual daily yield ranged from 0.06 to 8.4 kg while catch per unit effort in terms of quantity and biomass ranged 0.02-1.46 crab gear-1 day-1 and 1.1-213.54 g gear-1 day-1, respectively. The results showed that mud crab population in this study site was much higher than the population in the reforested (Walton et al., 2006, 2007) and natural mangroves (Lebata et al., 2007) with almost the same area. For 18 months of sampling (April 2002-September 2003), only 3,924 crabs were sampled in the natural mangroves while 10,504 in the reforested mangroves. Mud crab production in the present study site resulted in a yield of 21 kg ha-1 yr-1, 5 and 3 times higher than the yield reported in the natural and reforested mangrove areas, respectively. These results imply that habitat restoration can be very effective in restoring natural populations of mud crab.
  • Conference paper

    Development of immunostimulant for mud crab, Scylla serrata 

    RF Traifalgar - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Non-specific immune activitation is considered a potential prophylactic approach in the prevention of disease outbreaks in crustacean aquaculture. The present investigation evaluates the dietary supplementation of bacterial and algal derived immunostimulants including peptidoglycan, ergosan, mannan oligosaccharide and acidic polysaccharides from Ulva, Sargassum and Padina to enhance the immunological responses and resistance of Scylla serrata juveniles against white spot syndrome virus (WSSV) infection. Each of the test immunostimulant was optimized for dose and frequency of administration.

    Results showed significant enhancement of shrimp survival against WSSV infection if Mannan oligosaccharide is supplemented at 2000 mg kg-1 diet applied every 3 days. Optimum dose and frequency of application for peptidoglycan was determined as 1000 mg kg-1 diet applied every 3 days while a dose of 2000 mg kg-1 diet applied every 3 days was found optimum for ergosan. Enhancement of survival was also observed in crabs given the acidic polysaccharide extracts from seaweeds. Better survival was observed in the treatment receiving Ulva at 1000 mg kg-1 applied every 3 days. Similar dose and frequency were also observed to enhance the resistance of the juvenile crabs against WSSV when maintained with diets supplemented with Padina and Sargassum acidic polysaccharides. The high survival in these treatments is associated with the prominent enhancement of immunological responses including phenol oxidase activity, respiratory burst and total hemocyte counts. At optimum dosage and application frequency, these immunostimulants are observed to improve overall growth performance of the juvenile crab. These results suggest that dietary supplementation of peptidoglycan, ergosan mannan oligosaccharide, and acidic polysaccharides from Ulva, Sargassum and Padina at a dose described above can be used to boost the immunological response and enhance the resistance of S. serrata juveniles against WSSV infection.
  • Conference paper

    Handling, storage and transport conditions of mud crabs in trading centers 

    JP Peralta & JPD Chan - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    This study aims to improve the handling, storage and transport conditions of mud crabs. The usual practice of the crab growers in the Philippines is to bring the market size crabs to middlemen, brokers or operators of small trading centers immediately after harvest; then the crabs are brought to municipal traders or operators of bigger buying station. The crabs are sent to the exporters in Manila or Cebu. The crabs are exported mostly to Singapore, Taiwan, Hongkong and mainland China. The crabs are classified based on the species, body weight, sex, gonad maturity and intactness of limbs. Crabs are rejected for export when they are soft-shelled, very lean, or have incomplete limbs and abnormalities. Crabs with emaciated muscle (‘hagas’), ammoniacal odor (strong urine-like smell) and in an undesirable state are also rejected.

    This paper presents the initial results of the project on the Improvement in the handling, storage and transport of mud crabs under Sub-program C entitled Improvement of Feeds and Stock Management Practices in Mud Crab Grow-out Culture under the National Mud Crab Science and Technology Program. It also presents issues and concerns on the present practices, and presents possible recommendations.
  • Conference paper

    Development of aquasilviculture at BFAR-NBFTC, Pagbilao, Quezon 

    RE Dieta & FC Dieta - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Aquasilviculture technology verification project was conducted at the National Brackishwater Fisheries Technology Center (NBFTC) of the Bureau of Fisheries and Aquatic Resources (BFAR) in 1996-2000. Results indicated that given the proper technology, management and favourable market, and polyculture of high-value species (grouper (Epinephelus) and mud crab (Scylla)) will provide better return on investment. Dissemination of the technology through training started in 2001. In 2002, a 4-hectare undeveloped fishpond of NBFTC was converted into an aquasilviculture project to showcase the technical and economic feasibility of the technology with emphasis on the polyculture of mud crab, grouper and saline tilapia (Oreochromis) that would serve as a model livelihood project for coastal fisherfolk. In 2011, the BFAR launched the Philippine National Aquasilviculture Program to help restore mangroves that serve as breeding and nursery grounds of fish, and to provide livelihood projects through aquasilviculture to coastal fisherfolk. With increasing cost of development and management for aquasilviculture, integration of mangrove crab fattening and/or soft-shelled crab production have shown to improve profit under the present economic condition.
  • Conference paper

    Defects in the handling, storage and transport of mud crab 

    JP Peralta & DS Cheung - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
    Consumers prefer to buy live mud crabs (Scylla). Moribund and dead crabs have very low market value. Immediately after harvest, the crabs are tied to render their claws immobile. The time between harvest and arrival of crabs at the final destination is 3-5 days. During the holding and transport period, the crabs are no longer fed and are sometimes subjected to stressful conditions (e.g. high temperature) which may result to weight loss, muscle emaciation and other undesirable conditions of the crabs, and mortality. Likewise, ammoniacal odor (strong urine-like smell) that affects flavor is sometimes observed. Crabs with emaciated muscle and undesirable odor are considered rejects.

    This paper presents the initial results of the project on the Improvement in the Handling, Storage and Transport of Mud Crabs under Sub-program C entitled Improvement of Feeds and Stock Management Practices in Mud Crab Grow-out Culture under the National Mud Crab Science and Technology Program.

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