Present Status of Low Depth Shrimp Farming System with Special Reference to Soil-water Characteristics in South-West Region 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 Sadar Upazilla covering each union based on water depth. Among the ghers, 69% found between 1.5 < to < 3 ft depth, 17% below ≤ 1.5 ft and 14% ≥ 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 Bemarta Union under Sadar Upazilla at Bagerhat districts of Bangladesh over a growing cycle. Physico-chemical parameters of soil-water needed to be measured and analyzed by standard methods. Total yield (3414 kg/ha/cycle in T1, 2470 kg/ha/cycle in T2, 1482 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 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 once in daily and shrimp suitability and production ranged from (15-27)% and 247 kg/ha/cycle to 741 kg/ha/cycle. The present findings indicate that low depth gher comparatively gives a better result in fin fishes than shrimp/prawn and creates a hazardous environment for shrimp post larvae survives, viral death, health risk and economically not viable for sustainable shrimp production in Bangladesh.