salinitiesThe initial average body mass of the prawn were not signifi-cantly different (P > 0.05) at the commencement of the experiment.Significant differences in monthly average body mass wereobserved in different salinity treatment (Fig. 3). At the end of 60days culture period, prawn exhibited the lowest average growth(25.63 g) at 20 ppt and the highest average growth (34.97 g) at10 ppt. The highest weight gain was obtained in prawn culturedin 10 ppt (23.53 g) followed by 5–15 ppt, but did not differ signifi-cantly to each other (P > 0.05). The lowest weight gain was obtainedin 20 ppt (13.58 g) which differed significantly (P < 0.05) from othertreatments. This growth trend was also true for daily weight gains(Table 2). The specific growth rates (SGR) of prawn were also high-est when cultured in 10 ppt (1.86%/day) followed by 5 ppt, 15 pptsalinities and in freshwater (0 ppt) but differences among treat-ments were not significant (P > 0.05). Significantly lower SGR wasobtained in 20 ppt salinity treatment (1.26%/day) (P < 0.05). Thisgrowth trend was also similar in case of the percentage bodyweight gain (BWG %). The SGR in first month (30 days) and sec-ond month (60 days) differed significantly (P < 0.05). In case of 30days SGR, highest growth rate were obtained in freshwater (0 ppt)followed by 5, 10, 15 and 20 ppt salinities. In contrast, this trendwas just reverse in 60 days SGR. In 60 days SGR, highest growthrate was obtained in 15 ppt followed by 10 ppt but differencesamong them were not significant (P > 0.05) (Fig. 4). The survivalrate of M. rosenbergii after 60 days trial period was significantly high(P < 0.05) in freshwater (0 ppt) and decreased as salinity increased.The differences in survival rate between 0 ppt and 5 ppt as well asbetween 5 ppt and 10 ppt were not significant (P > 0.05) (Table 2).The physico-chemical parameters of pond water measured duringtrial period were depicted in Table 3.4