Assessment of the toxic effects of Cadmium on Clarias gariepinus (Burchell, 1822).

Abstract

The toxic effects of cadmium (CdCl2) on Clarias gariepinus in terms of physical and behavioural responses as well as 96 hrs LC50 were investigated. A total number of 150 samples of the fish were acclimated for a period of 14 days during which they were fed to satiation twice daily. The test was made up of five treatments with replicate in each case with the following nominal Cd concentrations: 00, 50, 80, 110, 140 and 170 mg/L. Each trough contained 10 fingerlings (10-20 mg). The experiment ran for a period of 96 hrs; and probit analysis was used in obtaining the 96hrs LC50. From the results: Cd toxicant elicited physical and behavioural responses such as lassitude, emaciation, frequent gulping and gasping for air at the surface of the trough, attempts to jump out of the trough, lacerations and exuding of blood from sides of the opercular and bulging of the abdominal region of the body before their eventual death in most cases especially in treatments with higher concentrations. The 96hrs LC50 was 79.72mg/L. There should be routine check on this important staple food especially those obtained from the wild to ensure that the level of contamination is within permissive limit by relevant authority as well as creating public awareness on the dangers of the subject matter.