Current status of farming practices of striped catfish, Pangasianodon hypophthalmus in the Mekong Delta, Vietnam

Aquaculture of catfish, Pangasianodon hypophthalmus (Sauvage), locally known as &ldquo;ca tra&rdquo;, and commonly referred to as striped catfish, river catfish and sutchi catfish, in Vietnam, having recorded a production of 683,000 tonnes in 2007, valued at about 645 million US$ is one of the largest single species based farming system, restricted to a small geographical area, in the world. The product is almost totally exported to over 100 countries as frozen fillets, as an acceptable alternative to white fish. Catfish is farmed mostly in earthen ponds, up to 4 m deep, in nine provinces in the Mekong Delta in South Vietnam. The results of the grow-out system of catfish farming in the Mekong Delta from a survey of 89 farms are presented. The farm size ranged from 0.2 to 30 ha with a mean of 4.09 ha. The frequency distribution of the yield in tonne/ha/crop and tonne/ML/crop corresponded to a normal distribution curve, where 75% of the farms yielded 300 tonnes/ha/crop or more. It was found that the yield per crop was significantly correlated (p &lt; 0.05) to stocking density, pond depth and volume but not to pond surface area. Yields per crop was significantly different (p &lt; 0.05) between upper and lower provinces of the Mekong Delta and water source (river versus channels), amongst others. It was evident that diseases and/or symptoms were observed to occur mostly in accordance with the onset of rains. In this paper the history of the catfish farming in the Mekong Delta is briefly traced, and current harvesting and marketing procedures as well as pertinent social elements of the farming community are dealt with.</div

Estimation of nitrogen and phosphorus in effluent from the striped catfish farming sector in the Mekong Delta, Vietnam

In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8&deg;33̕&ndash;10&deg;55̕ N, 104&deg;30̕&ndash;106&deg;50̕ E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P discharged in the production of a tonne of production was estimated.<br /