Identification of Physico-Chemical Factors Affecting The Growth of Macrobrachium Rosenbergii in Ponds

Abstract

This project thesis deals with the study of identification of physico-chemical factors of habitat which effect on the growth of Macrobrachium rosenbergii in ponds. The experiment was conducted into the research ponds located at the Khulna University premises during August to November of 2006. Twelve ponds were selected and they were stocked with three replications having densities of 500 PL/dec., 800 PL/ dec. 1000 PL/dec. and 958 PL/ dec. which were attributed as T1, T2 and T3 and Tc respectively. Physico-chemical parameters of the pond habitat and as well as growth of post larvae (in wt) were recorded at an interval of fifteen days during the experimental period. Among the various parameters eg pH, alkalinity, DO, hardness, sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (CI-), phosphate (PO4-3), ammonia (NH3+), some such as DO, Ca2+, Phosphate and alkalinity were identified as effective factors, which made a significant effect on the growth of M. rosenbergii. In Tc, better growth was recorded at 7.27 pH, 0.71mg/L phosphate, 0.07 mg/L ammonia, 19.04 mg/L Mg2+, 63.42 mg/L Ca2+, 190 mg/L hardness, 179.2 mg/L alkalinity, 38.32 mg/L chloride, 2.07 mg/L K+, 3.77p mg/L Na+ and 6 mg/L DO. In T1 better growth was recorded at 7.16 pH, 0.77 mg/L phosphate, 0.07 mg/L ammonia, 15.8 mg/L Mg2+, 57.43 mg/L Ca2+, 185 mg/L, hardness, 183.33 mg/L alkalinity, 39.15 mg/L chloride, 1.76 mg/L K+, 3.56 mg/L Na+ and 6.16 mg/L DO. In T2 better growth was recorded at 7.23 pH, 0.82 mg/L phosphate, 0.05 mg/L ammonia, 21.06 mg/L Mg2+, 60.08 mg/L Ca2+, 196 mg/L hardness, 170.8 mg/L alkalinity, 46.65 mg/L chloride, 1.6 mg/L K+, 3.56 mg/L Na+ and 5.83 mg/L DO. In T3 better growth was recorded at 7.26 pH, 0.73 mg/L phosphate, 0.07 mg/L ammonia, 19.44 mg/L Mg2+, 59.43 mg/L Ca2+, 203 mg/L hardness, 156.66 mg/L alkalinity, 43.48 mg/L chloride, 1.8 mg/L K+, 3.7 mg/L Na+ and 5.8 mg/L DO. In case of aquaculture it is very important to record physico-chemical parameters for better management.