Effect of the synthetic pyrethroid Deltamethrin and the neem-based pesticide Achook on the reproductive ability of zebrafish, Danio rerio (Cyprinidae)

In the present research, both male and female zebrafish, Danio rerio (Hamilton), were exposed to 96-h LC5 values of Deltamethrin (0.016 μg dm^-3) and Achook (0.025 μg dm^-3) for three months. The fish were then returned to normal water and allowed to breed to permit observations of fecundity and hatchability. The results show significant reductions in fecundity and hatchability in comparison to the control group. Fecundity was reduced by 54.12% in the fish treated with Deltamethrin and by 17.81% in those treated with Achook. Significant decreases in hatchability of up to 49.7% were noted in the Deltamethrin group and of 36.9% in the Achook treated fish. The number of unhatched/dead eggs increased significantly (P < 0.05 for each case). It was concluded that low concentrations (96-h LC5 values) of both pesticides can have a significant impact on the reproduction of zebrafish.