Abstract
Pesticides pose a continuous threat to coastal areas receiving direct pesticide applications or rainfall run-off from agricultural land. Pesticides can be acutely toxic to fish and other marine organisms and its effect on these organisms can be assessed using toxicity bioassays, a convenient tool used extensively worldwide. Aphanius dispar (killifish) was exposed to different concentrations of fenvalerate, fenpropathrin (synthetic pyrethroid pesticide) to determine (24 h) LC50. In addition, biochemical changes occurred due to exposure to pesticides, e.g. total tissue protein content, was also determined. The present results reveal that the LC50 values for two pesticides tested were (0.0165 ppm for fenvalerate and 0.0014 ppm for fenpropathrin) indicating high sensitivity of fish juveniles and that A. dispar responded differently to different pesticides. The two pesticides tested appear to have reduced total protein in muscle tissue of A. dispar indicating impairment of protein synthesis and severe physiological distress on fish juveniles. Long-term exposure of organisms to pesticides may pose a high risk of health hazard to the general public via consuming these toxic fishes.