Effects of Sevin (carbaryl insecticide) on early life stages of zebrafish (Danio rerio).

Sevin brand carbaryl insecticide is one of the most commonly used insecticides in the United States, with great potential for leaching into ground- and surface water reserves. Its possible teratogenic effects were tested on zebrafish eggs in four dilutions of decreasing concentration. The average mortality rate was low, indicating that Sevin does not directly kill embryos at these concentrations. Eggs and embryos were consistently smaller than the control starting at 24 h after spawning until hatching. Embryos in the highest concentration took up to twice as long to hatch as the control. This delayed hatching time increases vulnerability to predation. In addition, as minnows are lower on the food chain, bioaccumulation of Sevin in tissues may increase in larger predators, affecting their metabolism and reproduction.