Effect of Stocking Density on the Survival of Shrimp (Penaeus monodon) Post Larvae in Earthen Pond Acclimatization System.

Abstract

Shrimp PL acclimatization is an effective and established industry practice in the Satkhira District. The acclimatization of shrimp PL is highly demanded among the shrimp culturists and they believe that the earthen pond acclimatization shrimp PL would survive in higher percentage in the earthen ground. The present study was taken in Satkhira district from 22nd September 2004 to 26th September 2004 to establish suitable stocking density, its effect on survival and subsequent economic return from the operation. Three different stocking densities were taken and three replications were taken in 9 same sized ponds and the stocking densities were 800, 1200 and 1600 PL/m² as T1, T2, and T3, respectively. Before stocking, pond construction, fencing, shading, pond preparation etc. were conducted and stocking was done during afternoon and after stocking water quality were monitoring, the range of water temperature, dissolved oxygen, pH and salinity were 27 to 29°C, 4.7 to 7.88 mg/l, 7 to 4.5 and 23 to 25 ppt respectively and that were within the tolerance range. The average survival rates were 82.64±1.28, 72.73±4.82 and 57.78±1.95% for T1, T2, and T3 respectively. Total fixed cost was observed 43900 taka for all treatments, while total operating costs were 335016, 511704 and 673992 Tk/9 ponds/8 cycles (2 months) for T1, T2 and T3 respectively. The net returns were 64233.92, 29462 and -15821.36 Tk for T1, T2 and T3 respectively. The returns on investment were 16.95, 5.30 and -20.34% for T1, T2 and T3 respectively. From the present study T1 was found best where stocking density was lower than other treatments. This suggests that if the management strategies will be improved such as use of feed, water quality management, and aerators use etc. then higher survival rate would be found from high stocking density acclimatization pond.