Effects of the Herbicide 2,4-D on the Bottom Fauna of Fish Ponds

Abstract

Abstract Application of the herbicide 2,4-D at different rates (0.5, 2.5, 4.5, 6.5, 8.5, and 10.5 kg/hectare per year) increased the concentration of bottom fauna in fish ponds. Significant increases in bottom fauna were observed in the winter season, followed by lesser increases in monsoon and summer seasons. At 4.5 kg 2,4-D/hectare per year, survival of rohu (Labeo rohita), catla (Gibelion catla), mrigal (Cirrhinus mrigala), and common carp (Cyprinus carpio) was highest. At different rates of 2,4-D application, the yield of bottom-dwelling fish was higher than yields of column-dwelling fish. For optimum fish survival, growth of bottom fauna, and growth of bottom-dwelling fish, 4.5 kg 2,4-D/hectare per year is recommended as an ideal and economical rate. The concentration of bottom fauna in different months exhibited significant positive correlations with calcium carbonate, pH, and available nitrogen in pond soil (P < 0.05) and negative correlation with available phosphorus in soil (P < 0.01).