Quantifying sustainability indicators in striped catfish Pangasianodon hypophthalmus downstream and upstream ponds

To assess the potential for improving sustainability and efficiency in an important Vietnamese finfish culture, we quantified sustainability indicators for 2 downstream and 2 upstream 3 to 4 m deep ponds for striped catfish Pangasianodon hypophthalmus (Sauvage, 1878) production along the Mekong River, Vietnam. The resources used per kg fish produced were (downstream vs. upstream): 2.8 vs. 7.1 m3 water, 0.04 vs. 0.14 kWh energy, 0.06 vs. 0.11 h human labour and 0.06 vs. 0.15 g antibiotics (p < 0.05). The feed conversion ratio (kg feed dry matter per kg fish wet weight) was 1.50 vs. 1.65 and feed dry matter utilization efficiency was similar (28 vs. 30%) for both types of ponds (p > 0.05). Nitrogen and phosphorus utilization efficiencies were 44 vs. 40% for nitrogen (p < 0.05) and 17.7 vs. 17.6% for phosphorus (p > 0.05). An advantage of production in deep ponds is the breakdown of organic matter through denitrification and fermentation. Based on the difference between feed input and monitored outputs and sinks, an estimated 29–37% of dry matter volatilized as CO2 and 30–34% of nitrogen was lost as N2. A major disadvantage of the deep pond production system is its dependency on water exchange with the Mekong River, resulting in low biosecurity, which is aggravated by the lack of availability of disease-free fingerlings. Dealing with disease caused farmers to apply suboptimal feeding rations and to lengthen the culture period. Developing (semi-)closed systems that adopt elements from recirculation technology could improve both culture performance and sustainability.