Effect of Endosulfan and 2,4-Dichlorophenoxy AceticAcid on the Growth and Gonadal Development ofFreshwater Prawn Macrobrachium lamarrei

摘要

The freshwater prawn Macrobrachium lamarrd was subjected to acute 96 hr static bioassay toxicity test with the pesticide endosulfan and the herbicide; 2;4-dichlorophenoxy acetic acid and the LC; values were 0.009 ppm and 0.5 ppm respectively. Whenprawns were exposed for 30 days; under static condition; to five sub-lethal concentrations; viz.; 0.008; 0.007; 0.006; 0.005 and 0.004 ppm of endosulfan and 0.4; 0.3; 0.2; 0.1 and 0.05 ppm of 2;4-diclorophenoxy acetic acid; the growth and the gonado-somatic index GSI were found to decrease in direct relation to increase in the concentration of the toxicants. However; there was an increase in growth at lower concentrations of endosulfan and acceleration in gonadal development at low concentration of 2;4-dichlorophenoxy acetic acid.