Effects of Water Retaining on Water Depth and Fish Production through Clay-Coated Polythene Beds in Seasonal Ponds of North-Western Bangladesh

Abstract

Summer ponds in north-west Bangladesh are suffering from sandy soil and drought. From January to December 2017, the University of Rajshahi, Bangladesh, conducted an experiment to improve seasonal ponds' water retention capacity and productivity. In nine seasonal ponds, polythene and clay were used on the bottom of three treatments (T1, T2, and T3). Selected five controlled ponds were used to compare water depth and production. While the average water depth was above 3 feet (0.91 m) in controlled ponds only for 6 months, polythene-based model ponds lengthened water holding capacity with average water depths of 6.23 feet (1.87 m), 5.71 feet (1.71 m) and 5.07 feet (1.52 m) in T1, T2 and T3, respectively throughout the year. The average net production of the research ponds in eight months was 20.68 kg/decimal whereas it was only 4.35 kg/decimal for controlled ponds. T1 exhibited 2.07 fold greater water depth and 4.75 fold greater productions than controlled ponds. Net production (5908.59±72.72 kg/ha/8month) of T1 was significantly (P < 0.05) higher than T2 and T3. Thus, using polythene and clay in the pond bottom and covering it with water up to 8 feet (2.4 m) deep, will increase the water holding capacity and production of seasonal ponds.