Effects of Sub-Lethal Atrazine Concentrations on Embryogenesis, Larval Survival and Growth of African Catfish, Clarias gariepinus (Burchell, 1822)

Abstract

The toxicity of environmentally relevant concentrations of atrazine on exposed fertilized eggs of Clarias gariepinus was evaluated in a 96hour static non-renewal bioassay. After exposure to atrazine concentrations of 0 (control), 4, 8, 12, and 16 μgL-1 in water, first mitotic cleavage in the control occurred at 40 minutes after fertilization. The first cleavage did not occur in the 8 μgL-1 treatment group until 60 minutes after fertilization. Similar dose depended delayed cleavage was observed across atrazine exposed eggs. The first larvae emerged 22 hours from the time of fertilization at 27.00C in both control and atrazine treatment groups. However, hatching rates significantly differed between the control and atrazine exposed eggs (P