Seed production and grow-out of mud crab (Scylla paramamosain) in Vietnam
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Abstract
This manual provides information on the biology and techniques in the larval rearing, nursery and grow-out of the mud crab Scylla paramamosain.
Suggested Citation
Thach, N. C. (2009). Seed production and grow-out of mud crab (Scylla paramamosain) in Vietnam. (E. Quinitio, Ed.). Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department.
Type
BookISBN
9.78972E+12Series
Aquaculture extension manual; No. 42Format
vi, 24 p. : ill.
Koleksi
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Adoption of modified commercial scale mud crab hatchery and nursery systems in Alaminos City, Pangasinan
(Aquaculture Department, Southeast Asian Fisheries Development Center, 2017)Pangasinan’s vast fishpond and mangrove areas have not been fully tapped for mud crab (Scylla serrata) production. The main reason identified for this is the limited supply of crab seedstock. At present, there is no reliable source of seedstock in Pangasinan. The total requirement of Pangasinan for crab seedstock is estimated at 8.89 million based on the total area (ha) devoted to mud crab polyculture in the province. Mud crab growers in Pangasinan procure wild juvenile crabs from Cagayan, Bicol and Visayas but the volume is limited. Thus, an adoption of a modified commercial scale mud crab hatchery and nursery systems in Alaminos City would be helpful. A model mud crab hatchery will be constructed to enable the local government unit (LGU) of Alaminos City to produce seedstock in commercial quantity to boost the production in Pangasinan and nearby provinces. The hatchery aims to produce 480,000 juvenile crabs per year to supply the nursery and grow-out ponds. Likewise, the hatchery technology will promote the mud crab hatchery and nursery technologies in the city of Pangasinan and coastal towns (Infanta, Dasol, Burgos, Agno, Bolinao, Anda, Bani, Sual, Labrador, Lingayen, Binmaley, Dagupan City and San Fabian), and nearby provinces of La Union, Ilocos Sur, Ilocos Norte and Zambales. -
Overview of the mud crab industry in the Philippines
Quinitio, Emilia T.
(Aquaculture Department, Southeast Asian Fisheries Development Center, 2017)
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. -
Recent developments and enhancing transfer of the nursery technology for the mud crab Scylla serrata
; ; ; ; ; ; Quinitio, Emilia T. (Aquaculture Department, Southeast Asian Fisheries Development Center, 2017)
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.
