154 Asian Fisheries Science 32 (2019):154–161 Asian Fisheries Science 32 (2019):154–161 154 Shrimp Yield in Relation to the Ecological Parameters of an Organic Shrimp Model in the Mekong Delta of Vietnam: A Case Study ©Asian Fisheries Society ISSN: 0116-6514 E-ISSN: 2073-3720 https:// doi.org/10.33997/j.afs.2019.32.4.003 THO NGUYEN 1, *, TU THI KIM TRAN 2 , CHI THI HUE NGUYEN 2 1 Vietnam Academy of Science and Technology, 01 Mac Dinh Chi Street, Ho Chi Minh 028, Viet Nam 2 Ho Chi Minh City National University, Ho Chi Minh City, Viet Nam *E-mail: ntho@hcmig.vast.vn | Received: 12/03/2019; Accepted: 11/12/2019 Abstract 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, 1887- 1888]) 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. Keywords: mangrove, Naturland, organic shrimp, shrimp yield, Vietnam Introduction In the context of increasing demand for cleaner food production worldwide, organic shrimp model has been developed in the coastal areas of many countries in the tropics, such as Thailand, Bangladesh, Indonesia, India, Madagascar, and Vietnam (Paul and Vogl, 2012; Willer et al., 2014; iPFES, 2015). There are several organizations such as Ecocert (France), IMO (Switzerland), National Programme for Organic Production (India), and Japanese Agricultural Organic Standard (Japan) that have examined and certified organic shrimp products. According to Naturland’s standards (by IMO), shrimps of this model are cultured in the near-natural environment, preferably in polyculture systems, without using antibiotics and chemicals, and with special emphasis on protection of mangrove forests and mangrove ecosystems (Naturland, 2019). The near- natural environment polyculture system is expected to produce clean shrimp products while preserving the coastal environment. With the rising health and environmental awareness of global consumers, the organic shrimp model is expected to grow faster in the future (Mukul et al., 2013; https://aindustryreports.com). In Vietnam, the organic shrimp model was introduced in 1999 and first certified by Naturland in 2001 in the coastal part of the Mekong delta where shrimp aquaculture had a very long history and played a key role in supporting the coastal communities. This model was developed based on the background of the mixed shrimp-mangrove systems established in the 1980s in the area (Camimex, 2012). In this model, black tiger shrimp (Penaeus monodon Fabricius, 1798) are cultured at low densities in the mangrove forests, and often cultured with marine crab (Scylla serrata Forskal, 1775), blood cockle (Anadara granosa Linnaeus, 1758), and wild shrimps, Penaeus indicus H. Milne Edwards,