Survival and Growth of Macrobrachium rosenbergii (de Man) Juvenile in Relation to Calcium Hardness and Bicarbonate Alkalinity

摘要

Survival and growth of Macrobrachium rosenbergii juvenile (0.045 +- 0.007 g, 25 days old) were investigated under different calcium hardness levels from 92 to 384 mg/L CaCO_3 for 42 days. The maximum survival rate (100%) was observed at a calcium hardness level of 92 mg/L CaCO_3, while the lowest survival rate (60%) was recorded at the highest calcium hardness level of 384 mg/L CaCO_3. Maximum growth of the prawn (11.6 +- 2.7 mg/day) was observed at 132 mg/L CaCO_3. However, there were not significant (P>0.05) changes in growth at calcium hardness levels of 92 and 192 mg/L CaCO_3 The growth of the prawn declined significantly (P<0.05) at calcium hardness level of 228 mg/L CaCO_3 and above. Survival and growth study of M. rosenbergii juvenile (0.12 +- 0.03 g, 60 days old) was also done under different bicarbonate levels from 100 to 370 mg/L CaCO_3 for 60 days. Survival rate of the prawn was highly impaired at the highest bicarbonate levels tested while maximum survival rate (90%) was recorded at bicarbonate level of 100 mg/L CaCO_3. The highest growth (4.92 +- 0.13 mg/day) of the prawn was recorded at lowest bicarbonate level of 100 mg/L CaCO_3 tested and the growth significantly (P<0.05) declined at 205 mg/L CaCO_3 bicarbonate alkalinity and above.