Respiratory responses and behavioural anomalies of the carp Cyprinus carpio under quinalphos intoxication in sublethal doses
Sameer Gopal Chebbi, Muniswamy David*
ABSTRACT: A static renewal bioassay was conducted to determine the acute toxicity (LC50) of commercial grade organophosphate insecticide, quinalphos (25% emulsified concentration) to common carp, Cyprinus carpio. The acute toxicity of quinalphos to carp fingerlings exposed for 96 h was found to be 7.5 µl/l. The fish were exposed to sublethal concentrations (0.1LC50 and 0.2LC50) for up to 15 days. Fish in toxic media exhibited irregular, erratic, and darting swimming movements, hyper excitability, and loss of equilibrium and sinking to the bottom. Caudal bending was the chief morphological alterations during the exposure tenures. The carp were found to be under stress but mortality was insignificant in both sublethal concentrations. Considerable variation in respiratory rate was observed in both sublethal concentrations. The observed alteration in respiratory rates may be a consequence of impaired oxidative metabolism and elevated physiological response by the fish against quinalphos stress. The impairments in fish respiratory physiology and behavioural response even under recovery tenures may be due to slow release of sequestered quinalphos from the storage tissues.
Karnatak University's Research Laboratory, Environmental and Molecular Toxicology Division, Department of Zoology, Karnatak Science College, Dharwad-580 001, Karnataka, India