Acute toxicity of Cadmium and its bio-accumulation in the carnivorous fish species Channa marulius, Mystus seenghala and Wallago attu

Abstract

Acute toxicity of Cadmium (Cd) using 96 h LC50 and lethal concentrations was determined for the three fish species viz. Channa marulius, Mystus seenghala and Wallago attu. These toxicity tests were performed with three length groups (50, 100, 150 mm) of each fish species at constant water temperature (28°C), pH (8) and total hardness (250 mg L-1). Fish mortality data were analyzed using Probit analysis method at 95% confidence interval to calculate 96 h LC50 and lethal concentrations of Cd. At the end of acute experiments, the organs (gills, kidney, liver, muscles) of dead fish were analyzed for Cd accumulation. Among the three carnivorous fish species, M. seenghala showed significantly higher sensitivity towards Cd toxicity followed by W. attu and C. marulius. However, 50 mm length group of all the three fish species exhibited significantly higher sensitivity towards Cd, followed by 100 and 150 mm length groups with significant differences. The organs of all fish species showed significant variations in their ability to amass Cd. However, C. marulius exhibited significantly (p < 0.05) higher ability to amass Cd in its tissues followed by that of W. attu and M. seenghala. Among the fish organs, liver and kidney showed significantly higher ability to amass Cd during acute exposure of metal. This study will help in sustainable conservation of carnivorous fish species in the natural aquatic bodies of Pakistan.