THƯ VIỆN BỘ NÔNG NGHIỆP VÀ PHÁT TRIỂN NÔNG THÔN

Abstract. Dau Nhim snakehead (Channa sp.), a variant strain of the black snakehead (Channa striata Bloch, 1793), has been contributing significantly to freshwater farming in Vietnam. This study was conducted to determine the suitable stocking density of the fingerling stage of the Dau Nhim snakehead in order to supply breeding sources for farming. The fish (mean weight of 4.62 g) were randomly stocked at four densities of 50, 100, 150 and 200 ind m-3 with three replicates in 12 net hapas in an outdoor concrete tank and satisfactorily fed twice a day with pellet feed (35% crude protein) for 56 days. The fish growth performance was insignificantly different among the stocking densities, during the first 28 culturing days (p>0.05). Data at the experiment end showed a reduction in culturing efficiency with an increasing stocking density. In particular, the growth performance at 100 ind m-3 was significantly higher than that at 150 and 200 ind m-3 (p<0.05), while the feed conversion ratio (FCR) and the feed cost per production unit at the density of 100 ind m-3 were significantly lower (p<0.05). The survival rate ranged from 89.86 to 94.20% and no significant difference was found between stocking densities of 100 and 200 ind m-3 (p>0.05). All of the observed parameters had insignificant differences between stocking densities of 50 and 100 ind m-3 (p>0.05) during the experimental period. The present study indicated that 100 ind m-3 was the most suitable density for growing Dau Nhim snakehead fingerlings. It is recommended to culture Dau Nhim snakehead fingerlings through two stages, the first four weeks with a stocking density of 150-200 ind m-3, followed by 100 ind m-3 in the coming weeks.