Recently, succesfull aquaculture means to complete its cycle from hatchery to nursery and grow-out phases. The big challenge for the first phase is live foods as they provided subtantial nutrients, enzymes for most of early shrimp/fish larval stages (Bardach et al., 1972; Goodwin, 1976; Kinne & Rosenthal, 1977). Now a day, more than 80 % Artemia cysts have been used for marine shrimp hatcheries, but the main cyst source however come from the wild (e.g. collecting from salt lakes for USA, Russia, China) which are usually expensive and thus become bottle-neck to poor and developing countries. A succesfull story of Artemia farming in Vinh Chau (Vietnam) from introduction, adaptation of the original Artemia species (i.e. Artemia franciscana from solar saltworks in San Francisco, USA) to the new habitat (Vinh Chau), pond culture techniques and technology transfer to open out the possibility of fulfilling the need of Artemia cysts for local aquaculture development. In fact, the pond culture procedures of Artemia farming in solar saltwork in Vinh Chau through a so-called ?trial and error? to extensive ? semi-intensive and intensive required a lot of efforts from indoor to outdoor application. As in the first phase Artemia was stocked at a wider range of salinity (i.e. 60-150 ppt) at appropriate evaporation ponds, low stocking density, direct feeding with manure or rice-bran lead the cyst production varied around 30-50 kg wet weight/ha (in the period of 4 ? 5 months in the dry season) (Vu Do Quynh , 1991??; Brands, 1995; Nguyen Van Hoa, etal., 2007) ; later on, it was found that Artemia could invade to any area where salinity met in the range of 80-120 ppt (optimal range) and the key success as the fertilizer pond (kitchen pond) which needs at least 20-25 % the total culture area. Beside, the amount of manures and fertilizer had been fine-tuned according to the N:P ratio and the optimum rate of N:P varied from 3:1 to 5:1 (Nguyen Thi Ngoc Anh, 2009). Such a system was assigned as semi-intensive which could produce up to 70-90 kg wet weight/ha. Recently, an intensive system for Artemia farming in Vinh Chau being considered as an improvement of semi-intensive with the control in stocking density, pond level, aeration, supplementary feeding next to the biofloc technology application. The latest has been convinced not only to enhance cyst production as a whole but also to protect environment as less manures and fertilizers have been provided into the system. Thanks to the progress on Artemia farming technology in Vinh Chau and now a day per hectare of solar saltwork could produce as high as 150-200 kg wet weight/ha through out the dry season. As the main solar saltworks in the Mekong Delta (Vietnam), Vinh Chau and Bac Lieu now could produce up to 50 tons (wet weight) of Artemia cysts per year and to be worth about 2-3 million of US dollars. The most important issue is to sustain the local development of aquaculture activities as the cysts produced could be used for production of 7 billions of shrimp post larvae (PL), approximately.
Artemia farming in Vinh Chau now to be considered as a new approach to generate higher income for poor salt-farmer (i.e. salt-farmers could increase their profit 3-5 fold compared to traditional salt production). At the time being next to the cysts, Artemia biomass now being used for nurseries directly or incorporated as pellet for grow-out phase of a number of shrimp/fish species.
Tạp chí: Aquaculture and Environment: A focus in the Mekong Delta, Vietnam, Địa điểm: Trường Đại học Cần Thơ, Thời gian tổ chức: Ngày 3-5 tháng 4 năm 2014
Tạp chí: The 5th International Seminar of JSPS Core-to-Core Program: Collaborative Project for Soil and Water Conservation in Southeast Asian Watersheds. 6-7 August, 2014. Kyushu University, Japan
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
Điện thoại: (0292) 3 872 157; Email: tapchidhct@ctu.edu.vn
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