Jacob LT, Auta J, Habila JD and Yerima R
Cadmium toxicity on the aquatic environment has negative impact to fresh water organisms including fish such as C. gariepinus. However, the study evaluated the impact of short-term exposure for 96 hours of the developmental stages of C. gariepinus to waterborne cadmium (Cd2+). The different stages of development of the fish were gotten through artificial reproduction of C. gariepinus carried out in the Fishery/Hydrobiology Laboratory, Department of Biology, Ahmadu Bello University, Zaria, Nigeria. For the acute bioassay, 420 embryos of 12 hours post fertilization (hpf) and 180 larvae of 24 hours post hatching (hph) were randomly exposed in one-liter capacity plastic tanks containing 500 ml of Cd2+ concentrations of control (0.00), 1.80, 2.00, 2.20, 2.40, 2.60 and 3.00 mg/L) and (0.00, 0.80, 1.00, 1.20, 1.40 and 1.60 mg/L) respectively, for the 96-h. However, acute effects of Cd2+ to C. gariepinus reduced the percentage hatching from 88.89% in the control group to 52.22% in the group exposed to 3.0 mg/L Cd2+, caused malformation of embryos, and LC50 values of 2.55 and 1.33 for embryos and larvae respectively. Therefore, the major sources of cadmium (Cd2+ should be minimized from entering into the freshwater aquatic environment.
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