Shrimp Yield in Relation to the Ecological Parameters of an Organic Shrimp Model in the Mekong Delta of Vietnam: A Case Study

This study was carried out to observe the shrimp yield and ecological parameters of the organic shrimp model certified by Naturland at the coastal Tam Giang commune, Camau province, Mekong delta of Vietnam. The sampling of pond water and sediment and the collection of shrimp yield data were conducted in 2015. The results showed that the ponds were shallow (68.81 ± 3.40 cm) but the water and sediment were in general suitable for shrimp culture except in some cases when iron and oxygen levels were high. The total shrimp yield was low (355.4 kg.ha-1.year-1) and the wild shrimp, Penaeus indicus H. Milne Edwards, 1837, Penaeus merguiensis de Man, 1888 [in de Man, 1887-1888], Metapenaeus ensis (De Haan, 1844 [in De Haan, 1833-1850]) and Metapenaeus lysianassa (de Man, 1888 [in de Man, 18871888]) cultured together with Penaeus monodon Fabricius, 1798, contributed significantly (55 %) to the total yield. Positive correlations between the total yield with pHH2O (P < 0.05) and pHKCl (P < 0.001) suggested that shrimp grew well in neutral or near-neutral pond bottom. Yield of wild shrimp and the total yield were positively correlated with the water depth (both at P < 0.05). To improve pond conditions, it is recommended that the water depth be increased to about 80–90 cm, to avoid disturbance to the mangrove soil. In addition, the water level should be higher than the forest floor, and lime (CaO) should be applied to the pond sediment that is deposited on the dikes after harvest.