Báo cáo nghiên cứu khoa học CLAM CULTURE DEVELOPMENT IN THE INTERTIDAL AREA: EFFECTS OF STOCKING BIOMASS ON GROWTH, SURVIVAL AND PRODUCTION OF THE TWO SIZES CLAM Meretrix lyrata

Mục đích của nghiên cứu này là để nâng cao năng suất của nền văn hóa truyền thống của nghêu Meretrix lyrataSowerby, 1851 trong khu vực bãi triều Bắc Trung Bộ Việt Nam. Bài viết này chủ yếu tập trung vàomô tả tác động của sinh khối thả giống vào sản xuất nghêu.Thí nghiệm gấp ba đã được tiến hành trong 50m2 lô ngẫu nhiên được đặt trong các khu vực bãi triềuđánh giá ảnh hưởng của mật độ nuôi sinh khối tăng trưởng, hiệu suất sống sót và chất lượng của nghêu Meretrixlyrata Sowerby, 1851....
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Báo cáo nghiên cứu khoa học " CLAM CULTURE DEVELOPMENT IN THE INTERTIDAL AREA: EFFECTS OF STOCKING BIOMASS ON GROWTH, SURVIVAL AND PRODUCTION OF THE TWO SIZES CLAM Meretrix lyrata "Collaboration for Agriculture and Rural Development (CARD) Program CLAM CULTURE DEVELOPMENT IN THE INTERTIDAL AREA: EFFECTS OF STOCKING BIOMASS ON GROWTH, SURVIVAL AND PRODUCTION OF THE TWO SIZES CLAM Meretrix lyrataProject title: Development of clam culture for improvement and diversification of livelihoods of the poor coastal communities in Central VietnamProject code: CARD 027/05VIE Nhu Van Can1, Chu Chi Thiet1 and Martin S Kumar2Authors:Project implementing organizations: 1 Aquaculture Research Sub-Institute for North Central (ARSINC) 2 South Australian Research and Development Institute (SARDI), AustraliaSUMMARYThe aim of this study is to improve the productivity of traditional culture of clam, Meretrix lyrataSowerby, 1851 in the intertidal area of North Central Vietnam. This paper is mainly focused ondescribing the impact of stocking biomass on the production of clam.The triplicate experiment had been conducted in 50m2 plots randomly placed in the intertidal areas toevaluate the effects of stocking biomass on survival, growth performance and quality of clam Meretrixlyrata Sowerby, 1851. The two stocking sizes (Mean±SD, cm) at shell length of 1.0±0.2 and 1.7±0.1were scattered at different biomass: 0.05, 0.1, 0.2, 0.3 kg.m-2 and 0.34, 0.68, 1.36, 2.03 kg.m-2 andnamed as T1, T2, T3, T4 and T5, T6, T7, T8 respectively. Results shown that meat ratio of the clamwere similar regardless of different stocking biomass. The fatty acids were rich in highly unsaturatedfatty acids especially docosahexaenoic acid but were variable. In contrast, growth and survival of theclam were strongly affected by the stocking biomass in which, the lower stocking biomass resulted inhigher specific growth rate (SGR) and survival rate. The biomass gained therefore was reducedaccordingly with increasing of stocking biomass although the increase of final production was evident.However, SGR and survival of the treatments T1, T2 and T3 were not significantly different explainedfor the highest net profit and investment return of the treatment T3. The stocking biomass of 0.2 kg.m2therefore, was recommended to maximize profit of clam cultivation. 2000; Shpigelr, 1996; Zhang, 2006) and the1. Introduction use of clam for water quality improvementAmong mollusc species, the bivalve shellfish (Jara-Jara et al., 1997; Shpigel, 1990). Inmeat were not only a popular seafood, but also Vietnam, the endogenous brackish water clamwere regarded as the most ecologically Meretrix lyrata is an emerging cultured speciesefficient forms of aquaculture as they are low for coastal aquaculture because this is atropic level animals. Besides, bivalve shellfish popular seafood in the national andare filter feeders which can also be used as a international markets. M. lyrata distributesbio-filter for water quality improvement naturally in the intertidal area of southern coast(Mazzola, 2001; Shpigel, 1991; Shpigel et al., and known as Ngheu Ben Tre because the1997; Shpigel et al., 1993) and thus contribute exploited production mostly comes from Bento the sustainable aquaculture development. Tre province, South of Vietnam. Due to highClams belong to bivalve shellfish but they are consumption demand, the intertidal areas aredifferent from the others as they live on the being used for the cultivation of M. lyrata andbottom. Studies have been conducted for these practices expanded to the northernvarious clam species for production (Cigarrıa, 166 CARD 027/05 VIE – Development of clam culture in Central Vietnamcoastal provinces such as in Nam Dinh, Thanh The small clam seed at shell length of 1.0±0.2Hoa, Nghe An, Ha Tinh. However, the clam cm were scattered at 4 different biomass: 0.05, 0.10, 0.20 and 0.30 kg.m-2 and named as T1,production is still very unstable andunpredictable because of poor management T2, T3 and T4 respectively. The bigger size ofdue to lack of technical knowledge on clam clam seed at shell length of 1.7±0.1 cm wereculture practice. The technical information on stocked at 4 different stocking biomass: 0.34, 0.68, 1.36 and 2.03 kg.m2 and named as T5,clam culture still has been very limited. It wastherefore, necessary for research to establish a T6, T7 and T8 respectively. This experimentstandard clam aquaculture protocol to enhance was terminated after 165 days of rearing.the production and profit of clam culture.Among the factors that affect growth andproduction, feed and feeding of clam havebeen regarded as the ...