Effect of herbicides on fish and histological evaluation of common carp (Cyprinus carpio)

Toxicity of the herbicides like 2, 4-D NA salt, glyphosate and paraquat were tested, fish was investigated in laboratory and toxicity tested with common carp. Median lethal concentrations were determined in acute tests. The 96 h LC50 value was 100, 86 and 26 mg/L were tested. The experiment was laid out in a randomized block design with four replications. Screening of different herbicides was taken up in cement pots of dimension 2' x 2.5' x 2' with water filled up to three fourth of the pot’s height, holding ten water hyacinth plants and each treatment were introduced ten fish fingerlings. Three different species tested viz., common carp, mrigal and rohu fishes were reared. Fish was exposed to acute toxicity of herbicides and gills, brain, liver and kidney structure were studied. In different concentration of herbicidal changes were observed in the vital organs and was confirmed by histological analysis. Among the herbicides applied, glyphosate significantly influenced with the least fish mortality percentage of 23.0, 16.0 and 20.0 on common carp, mrigal and rohu at 4 DAS, respectively. The same herbicides were found in the lesser imparted of tissues such as gills, brain, liver and kidney of the fish was examined.