Effect of cypermethrin on breeding performances of a freshwater fish, Labeo rohita (Hamilton)

Abstract

The effect of cypermethrin, a synthetic pyrethroid, on the breeding performances in the freshwater fish, Labeo rohita (Hamilton), has been investigated in the present study. Breeding of Labeo rohita was conducted after treating with three sublethal concentrations of cypermethrin, i.e. 0.16, 0.40, and 0.80 μl l−1, respectively, for 96 h. The present investigation shows that the significant reduction (P< 0.01) of the total number of eggs, total amount of egg (litre), total amount of egg (litre per kilogram of body weight), fertilization percentage, and expected fertilized egg number at the concentrations of 0.40 and 0.80 μl l−1 of cypermethrin. Also, the reduction in hatching percentage, expected number of hatchling, and expected number of hatched larvae were significantly different (P <0.01) between the treatment and the control at all cypermethrin concentrations. No significant differences for the 96 h survivability of hatched larvae were reported at 0.16 and 0.40 μl l−1 levels of cypermethrin, whereas significant differences (P< 0.05) were reported at 0.80 μl l−1.