Pond Bottom Management at Commercial Shrimp Farms in Chantaburi Province, Thailand

Abstract

Most shrimp farmers in Chantaburi Province, Thailand, use water jets to dislodge sediment from empty pond bottoms, and wastewater is held for sedimentation before discharge into natural waters. Other pond bottom management practices used by a few farmers are sediment excavation, leave sediment but till entire pond bottom, and no mechanical treatment. All four methods of pond bottom treatment are followed by sun drying for 30 d. Soil organic carbon concentration in ponds following dry‐out seldom exceeded 2%. Although shrimp production in 24 ponds supplied by the same source of water was negatively correlated with increasing soil organic carbon concentration (r = −0.582), this observation does not confirm a causative relationship. Moreover, in trials conducted at Burapha University, Chantaburi Campus, bottom soil organic matter concentration following dry‐out differed little irrespective of treatment method. Lower soil moisture concentration revealed that dry‐out was more complete with sediment removal than without, but better dry‐out resulted in lower soil pH. Removal of sediment by excavation or flushing is expensive, and natural dry‐out combined with liming and occasional sediment removal should be investigated as a less expensive and more environment‐friendly alternative to removing sediment after each crop.

Environmental impacts of shrimp aquaculture: the case of Chandipur village at Debhata upazila of Satkhira district, Bangladesh

“…• Water Quality: Water quality problems are increasing in shrimp farming areas because of excessive feeding, effluents and high stocking of foods. Poor water quality causes diseases, mortality, low production of shrimp and in some places it has become impossible to continue shrimp farming any more (Yuvanatemiya et al 2011). So to gain profit from shrimp and also to save environment water quality has to be maintained.…”

“…Bangladesh has a huge coastal tidal area which is considered favourable for shrimp farming and 0.276 million hectares of land are currently under brackish water shrimp cultivation. During 2010-2011 the country produced 182,471 metric tons of large (121,203 metric tons) and small shrimp (Fisheries Resources Survey System, 2010-2011 and earned US$ 437.40 million from both frozen shrimp and fishes (Bangladesh Frozen Food Exporters Association 2012). South-western and south-eastern parts of the country are favourable for shrimp cultivation.…”

Resource Use Assessment of Shrimp, Litopenaeus vannamei and Penaeus monodon, Production in Thailand and Vietnam

“…Several surveys of resource use in shrimp farming have been conducted in addition to LCA efforts mentioned earlier. These include Henriksson et al () (http://www.media.leidenuniv.nl/legacy/d35-final-case-study-report.pdf), Jahan et al (), Gräslund et al (), Yuvanatemiya et al (), Global Aquaculture Alliance (), and many reports prepared by the World Bank, Network of Aquaculture Centres in Asia‐Pacific, World Wildlife Fund, and Food and Agriculture Organization of the United Nations Consortium Program on Shrimp Farming and the Environment in the early 2000s (http://www.library.enaca.org/Shrimp/Publications/DraftSynthesisReport-21-June.pdf).…”

Water Pollution

“…Moreover, it is common practice in shrimp farming in Asia to wash bottoms of empty ponds between crops with water from high-pressure nozzles to remove sediment and lessen oxygen demand during the next crop (Yuvanatemiya et al 2011). Production may be further intensified by dredging organic sediment from bottoms during the crop to reduce oxygen demand within ponds.…”

“…A reservoir also may be used to facilitate harvest without discharge of effluents to natural waters ( Fig. Effluents from washing pond bottoms with high-pressure streams of water is particularly concentrated in suspended solids and should be held in a sedimentation basin before release to the environment (Yuvanatemiya et al 2011). Resuspension of sediment from empty ponds by rainfall can be a source of suspended solids in farm effluents.…”