No abstract

The effect of toxic compounds are variable among living organisms in different habitats. Toxicity tests are conducted to measure the effects of different pollutants on one or more species of organisms and in the form of LC 50s , assist in the development and application of water quality criteria for the protection of the aquatic environment. Active tilapia, Oreochromis niloticus, samples with size ranging between 4 and 6 cm standard length were exposed to different concentrations (between 0 and 30 µg/l) of Deltamethrin for 96 h in 50 l glass aquaria. This was to assess the dose-response of O. niloticus to different concentrations of the pesticide, and to estimate the LC 50 using Probit analysis. The very low LC 50 value of 15.47 µg/l obtained indicates that Deltamethrin is highly toxic to O. niloticus. This LC 50 value should serve as a guide for the application of Deltamethrin in agriculture. Further study into the processes and mechanism by which Deltamethrin adversely affects the physiology of fishes have been recommended.