Báo cáo: "AQUACULTURE COMPENDIUM – CAB INTERNATIONAL CASE STUDY"

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In Vietnam, pond culture of marine finfish including mullet, milkfish and seabass has been developed since the 1960s (Dao, 1996) and significant expansion took place in the early 1990s...

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AQUACULTURE COMPENDIUM – CAB INTERNATIONAL CASE STUDY Grouper pond culture in Khanh Hoa, Vietnam TITLE OF CASE STUDY: SUMMARY In Vietnam, pond culture of marine finfish including mullet, milkfish and seabass has been developed since the 1960s (Dao, 1996) and significant expansion took place in the early 1990s with the appearance of a live fish market. Groupers (Epinephelus akaara, E. bleekeri, E. coioides, E. fuscoguttatus, E. malabaricus, E. merra, and E. sexfasciatus) are currently among the major cultured species. There are approximately 500 ha of coastal pond culture of marine finfish in Vietnam producing more than 1,000 t of products, mainly groupers with a farm gate value of more than VND100 billion (more than US$7 million) in 2003. Khanh Hoa, a province in the south of Central Vietnam with an area of 5,258 km2 and a population of approximately 1 million, is one of major localities producing groupers in ponds with a total estimated production of 100 t in 2003. This case study reviews the current status of pond culture of groupers, and identifies major technical, economic and social constraints to further development in Khanh Hoa province as well as elsewhere. NON-ENGLISH SUMMARY (Arial Unicode pt11) Ở Việt Nam, nghề nuôi đìa cá biển như cá đối, cá măng biển và cá chẽm đã phát triển từ những năm đầu thập kỷ 1960 và nghề này phát triển mạnh mẽ vào đầu những năm 1990 vớI sự xuất hiện thị trường cá tươi sống. Cá mú/song (Epinephelus bleekeri, E. akaara, E. sexfasciatus, E. malabaricus, E. coioides, E. merra, và E. fuscoguttatus) hiện nằm trong số những đốI tượng nuôi chính. Hiện có khoảng 500 ha vùng biển ven bờ được xây dựng thành các ao đìa nuôi cá biển trên tòan quốc. Những ao đìa này đã cung cấp trên 1000 tấn sản phẩm, chủ yếu là cá mú với giá bán tại đìa trên 100 tỷ đồng (trên 7 triệu Đô-la Mỹ) vào năm 2003. Khánh Hòa, một tỉnh ở Nam Trung bộ Việt Nam, có diện tích 5258 km vuông vớI dân số khoảng một triệu người, là một trong những địa phương chính nuôi cá mú đìa vớI sản lượng ước đạt 100 tấn vào năm 2003. Bài viết này đánh giá hiện trạng nghề nuôi cá mú đìa, và xác định các trở ngại chính về các khía cạnh kỹ thuật, kinh tế và xã hội đối với sự phát triển nghề này tại tỉnh Khánh Hòa cũng như những nơi khác. BACKGROUND Khanh Hoa province in the south of Central Vietnam has an area of 5,258 km2 and a population of approximately 1 million. Four of the six districts (Cam Ranh, Nha Trang, Ninh Hoa, Van Ninh) are located along the coastal area and there is one island district - Truong Sa (Spratly). Khanh Hoa has a 200 km long coastline with a sea area of more than 400,000 km2 including the Spratly archipelago (Le, 1998). The climate is tropical and monsoonal. The annual average temperature is about 26-27°C but ranges from a monthly average of 24°C in January to monthly averages over 28°C from April - September, with minima of 14.5-15°C to maxima of 39-40°C in certain years. The average rainfall is about 1,500 mm with 80% in a 4-month rainy season from September - December (CCHS, 1995). Khanh Hoa has a twisting shore line with many shelf bays and islands which contributes to making Khanh Hoa one of the biggest producers in Vietnam in coastal aquaculture, especially grouper, lobster and shrimp culture. 1 VN35-Grouper pond culture
In Vietnam, pond culture of marine finfish, including milkfish, mullet and seabass, has been developed since the 1960s (Dao, 1996). In Khanh Hoa, grouper was cultured initially in 1988 and significant expansion took place in 1990 with the appearance of a live fish market. The development of grouper pond culture underwent ups and downs due to technical and socio- economic circumstances such as outbreaks of shrimp disease and severe acute respiratory syndrome (SARS). Recently there have been 85 grouper farms of approximately 1 ha each, mainly in Cam Ranh and Nha Trang. Local farmers normally raise grouper in failed shrimp ponds with a similar growth rate to those in cages but with a higher survival rate and easier management in ponds. The seed supply is mainly from the wild; however, local hatcheries and imported seed have increased in recent years. Feed for grouper is mainly marine trash fish including anchovy, cardinal fish and lizard fish, but sometimes tilapia harvested from brackishwater ponds that received polluted water from the surrounding community and overhung latrines. In the past, diseases rarely occurred in groupers but recently there have been some diseases in cultured groupers in some ponds. However, the average survival rate is as high as 70 - 80%. The estimated total annual production of farmed grouper in Khanh Hoa is currently about 100 t a year with a farm gate value of nearly US$ 0.8 m, about 10% of the total national production. Grouper pond culture is a profitable industry and creates employment opportunities for local village people, especially in places where pond shrimp culture failed. DESCRIPTION OF ISSUE OR PRACTICE Seed Grouper species cultured in ponds are Epinephelus akaara, E.bleekeri, E. coioides, E. fuscoguttatus, E. malabaricus, E. merra and E. sexfasciatus. Initially, seed was only from the wild but in recent years, seed of some species has been produced in hatcheries or imported from Taiwan to augment wild seed. Grouper Culture Cycle The grouper culture cycle usually runs for 8-10 months, from January or March. Ponds are cleaned after the final harvest. Normally 9 months after stocking grouper, farmers begin to harvest grouper for sale, mainly through middlemen for export to China, Hong Kong. Feed Previous studies (Nguyen and Hambrey, 1998) have shown that only whole fresh trash fish are used and that the food conversion ratio (FCR) in cage culture, averaging 5.9 (fresh weight), is significantly higher than that for pond culture of grouper where the average FCR is 4.3. Trash fish used for grouper culture include anchovy (Stolephorus sp.), flat fish (Solea sp.), lizard fish (Saurida spp.), pony fish (Leiognathus spp.), red big-eye (Priacanthus macracanthus), sardine (Clupea leiogaster) and scad (Decapterus sp.) as the main species, but there are many other species in smaller amounts as well as small crabs and shrimps. The preferred fish are anchovy and lizardfish for less than 200 g and larger size groupers, respectively. Feed costs comprise around 18% of the farm gate price of grouper. Disease In the past, diseases of groupers rarely occurred. Recently, there have been some diseases in cultured groupers in some ponds such as black gill, red gill, white spot, ulcerative body syndrome, swelling abdomen and vitamin deficiency. Some preliminary studies (Dam, 1998) showed that the main pathogens occurring in infected groupers (mainly E. malabaricus) were Contracaecum sp., Pseudorhabdosynochus sp., Rhiphidocotyle sp. and Trichodina sp. 2 VN35-Grouper pond culture
Economics The estimated total annual production of farmed grouper in Khanh Hoa is currently about 100 t with a farm gate value of nearly US$ 0.8 m (VND 120,000 kg-1 or US$ 8 kg-1). The average profit margin is 20%. Therefore, grouper pond culture is a profitable industry. It involves approximately 85 farmers/households and creates many employment opportunities for local village people. However, the stability of the market is one of the major concerns of the farmers. Further Research Needs • Grouper seed for pond culture is sourced mainly from the wild. In the long-term this is unlikely to be sustainable. There have been some successful experiments on seed propagation of grouper at the Research Institutes for Aquaculture 1 and 2 (RIA Nos. 1 and 2) recently. However, much work remains to be done. • The feed used is mainly trash fish and small shellfish. The sustainability of this feed supply for the long-term development of grouper pond culture industry is also questionable. Compound feeds, using a higher proportion of non-fish protein need to be developed. • Diseases of cultured grouper have occurred commonly in some areas but little is known about the diseases. Additionally, aspects related to the live grouper market such as market structure and stability and its potential expansion should be studied. 3 VN35-Grouper pond culture
CONTEXT COUNTRIES Vietnam CULTURED SPECIES Epinephelus akaara E. bleekeri E. coioides E. fuscoguttatus E. malabaricus E. merra E. sexfasciatus AQUATIC DISEASES Black gill Red gill Swelling abdomen Ulcerative body syndrome Vitamin deficiency White spot ECOSYSTEMS Tick Ecosystem √ Bays √ Estuaries √ Lagoons √ Peri-urban areas √ Rural areas GROWOUT PRODUCTION SYSTEMS Tick Growout system √ Ponds 4 VN35-Grouper pond culture
PARTICIPANTS Organizations Organization Address Web Address (URL) University of Fisheries 2 Nguyen Dinh Chieu, Nha Trang, Vietnam Individuals √ Development Agents - Government and Non-Government √ Aquaculturists √ Extension officers √ Research, Education & Training √ Researchers √ Producers, Investors, Consumers √ Small-scale producers ISSUES √ Production systems: technology and its management √ Seed √ Species availability and seed supply √ Feeds Extension √ Sustainable Development √ Sustainable environmental development √ Livelihood issues √ Poverty alleviation √ Integrated resource management and coastal zone management (CZM) REFERENCES CCHS, 1995. Characteristics of climate and hydrology of Khanh Hoa. Nha Trang, Vietnam: Centre of Climate and Hydrology of the South, 191 pp. In Vietnamese. Dam BL, 1998. Study on parasites on cultured and wild caught groupers in Khanh Hoa. B.Sc. Thesis. Nha Trang, Vietnam: University of Fisheries, 71 pp. In Vietnamese. Dao MS, 1996. Marine fish culture in Vietnam. A paper presented at the NACA Workshop on Aquaculture of Coral Reef Fishes and Sustainable Reef Fishes, 4-8 December 1996, Kota Kinabalu, Sabah, Malaysia. 10 pp. NACA, Bangkok, Thailand. 5 VN35-Grouper pond culture
Do MD, 2003. Technical, socio-economic and market characteristics of the grouper culture industry in Khanh Hoa. B.Sc. Thesis. Nha Trang, Vietnam: University of Fisheries, 45 pp. In Vietnamese. Le AT, 1998. The sustainability of grouper seed supply to the aquaculture industry in Khanh Hoa, Vietnam. M.Sc. Thesis. Bangkok, Thailand: Asian Institute of Technology, 112 pp. Le AT, Nguyen TN, Hambrey JB, 2000. Status of Cage Mariculture in Vietnam. In: Liao IC, Lin CK, eds. Cage Aquaculture in Asia: Proceeding of the First International Symposium on Cage Aquaculture in Asia. Manila, Philippines: Asian Fisheries Society and World Aquaculture Society - Southeast Asian Chapter, 111-123. Nguyen VT, Hambrey JB, 1998. Grouper culture in Vietnam. Infofish International, July/August, 4(98):30-35. TEXT SECTIONS Summary Non-English Summary Background Description of Issue or Practice Seed Grouper Culture Cycle Feed Disease Economics Future Research Needs References ILLUSTRATIONS Type: Immediate Please supply a clear, descriptive caption for each Rights to illustration held by? Pic Slide return illustration (supply on a separate sheet if No. Print required? necessary) Artwork? (please tick) 1 Wild grouper seed scanned Le Anh Tuan 2 Hatchery grouper seed scanned Le Anh Tuan 3 Push net used for catching wild grouper scanned Le Anh Tuan seed 4 Bamboo traps used for catching wild scanned Le Anh Tuan grouper seed 5 Grouper pond in front of the house scanned Le Anh Tuan 6 Grouper pond with paddle wheel scanned Le Anh Tuan aerator 7 Preparing trash fish as feed for grouper scanned Le Anh Tuan 8 Crabs and shrimps used as feed for Taken Le Anh Tuan grouper digitally 9 Feeding grouper scanned Le Anh Tuan 6 VN35-Grouper pond culture