Sub-lethal concentrations of monocrotophos affect aggressive behavior of the fishes Astyanax altiparanae Garutti & Britski (Teleostei, Characidae) and Oreochromis niloticus (Linnaeus) (Teleostei, Cichlidae)

This study investigated the effects of sublethal concentrations of the pesticide monocrotophos (organophosphate) on the agonistic behavior of two fishes species, Astyanax altiparanae Garutti & Britski, 2000 (lambari) and Oreochromis niloticus (Linnaeus, 1758) (Nile tilapia). Sublethal concentrations of the pesticide for the two species were determined and lambari was more resistant than Nile tilapia. The sublethal concentrations were smaller than 400 mgl-1 for lambari and 20 mgl-1 for Nile tilapia. The two species were tested in grouping conditions (triads) and isolation, under monocrotophos c...