Behavioral and morphological changes in fresh water fish, Channa punctatus under the exposure of Cadmium

Abstract

Heavy metal contamination in fresh water bodies is of great concern owing to their toxicity, persistence and bioaccumulation. The current study deals with the acute toxicity of cadmium to fresh water fish, Channa punctatus. The objective of this study was to grasp the link between mortality and abnormal behavioral and morphological changes of C. punctatus exposed to cadmium chloride. Static bioassay tests were carried out to evaluate LC50 value of Cadmium (Cd) for fresh water fish, C. punctatus as well as the behavioral responses and morphological changes were also observed. Fish after treatment with various concentrations of cadmium chloride for different exposure period the percent mortality was recorded. The lowest cadmium chloride concentration at which mortality was observed as 45 mg/l. The first death of experimental fish was recorded as 125 mg/l at 24 hrs. of exposure. After 96 hrs. LC50 value of cadmium (Cd) was found to be 80.62mg/l. The major behavioral responses observed during the experiment were restlessness, jumping, erratic swimming, gulping of air at the surface, loss of equilibrium, sluggishness,opercular movements and fishes lied on the water surface before death and morphological changes like, discoloration of skin, pigmented patches on body, shedding of scales, sedimentation of chemical on body, mucous secretion, and ballooning were observed in exposed animals. The observed data showed that C.punctatus can be used as a good bio-indicator for heavy metal contamination in fresh water bodies.