Abstract:
The acute toxicity of Abate and Filariol to the guppy, Poecilia reticulate Peters and the Nile tilapia, Tilapia nilotica Linn. was conducted by static bioassay test. The results showed that Filariol was more toxic to the guppy than Abate; the 96 hr LC₅₀ values were 8.58 and 210.15 ppm, respectively. The thresholds of toxicity of both chemicals were very close to the 96 hr LC₅₀ values being at 8.40 and 210.50 ppm, respectively. The safe concentrations of Filariol and Abate for the guppy would be 0.43 and 10.53 ppm, respectively. Filariol was also more toxic to the Nile tilapia than Abate; the 96 hr LC₅₀ values were 13.34 and 22.39 ppm, respectively. The thresholds of toxicity, which were very close to the 96 hr LC₅₀ values, were at 13.20 and 22.20 ppm, respectively. The safe concentrations of the two larvicides for the Nile tilapia would be 0.67 and 1.12 ppm, respectively. From the chronic toxicity studies, it was found that Abate at 1 and 10 ppm and Filariol at 1.5 ppm had no effect on the mortality and growth rate of the Nile tilapia and both sexes of the guppy (P < 0.05). Filariol at 9 ppm was found to have effect on the mortality and growth rate of the guppy (P > 0.05), but it had no effect on the mortality and growth rate of the Nile tilapia. The water quality analysis showed no differences between the control and the treatments (P < 0.05). It was concluded that water qualities had no effect on the mortality and growth rate of the fish.