Study on low depth shrimp farming system with special reference to soil-water characteristics in Sathkhira districts of Bangladesh

Management of soil and water quality parameters is important catalysts for gaining sustainable fish production in Bangladesh. In this context, a comprehensive survey was done to categories existing shrimp farms locally called ghers of Tala Upazilla of sathkhira districts covering each union based on water depth. Among the ghers, 56% found between 1.5 < to < 3 ft depth, 19% below ≤ 1.5 ft and 25% ≥ 3 ft and an investigation was carried out to assess soil-water quality parameters and production performance of 9 selected low depth shrimp ghers in Khesra Union under Tala Upazilla at Sathkhira districts of Bangladesh over a growing cycle. Physico-chemical parameters of soil-water needed to be measured and analyzed by standard methods. Total yield (260 kg/ha/cycle in T1, 63 kg/ha/cycle in T2, 70 kg/ha/cycle in T3) of fishes was also calculated from the stocking and harvesting data. Most of the parameters of soil and water correlated significantly with each other suggesting a high degree of interactions between different parameters in the system. A pattern of qualitative and quantitative difference of zooplankton over phytoplankton was also recorded in these farms Therefore, a high degree of salinity, Water level fluctuation and iron deposition in waters was also documented. However, considerably lower concentrations of phosphorus in the soil indicated a net retention and trapping of phosphatic nutrients in the environment. Moreover cropping pattern was two cycles (fishes single, paddy single) per year, feeding frequencies was irrigullar and shrimp suitability and production ranged from (0-15)% and 63 kg/ha/cycle to 260kg/ha/cycle. The present findings indicate that low depth gher comparatively gives a better result in fin fishes than shrimp and creates a hazardous environment for shrimp post larvae survives, viral death, health risk and economically not viable for sustainable shrimp production in Bangladesh.