Uso de juvenis de peixes carnívoros nativos no controle da ictiofauna invasora na bacia do rio Paraná.

Abstract

We experimentally evaluated in microcosms, the potential of three native carnivorous fish species (Salminus brasiliensis, Brycon orbignyanus and Pseudoplatystoma corruscans) to control some invasive fish species in the Paraná River Basin and the role of habitat complexity in these predator-prey interactions. From a similar experimental protocol, three papers were elaborated. In every one of them prey consumption patterns showed by each predator species were assessed through individual trials. Three invasive (Cichla piquiti, Oreochromis niloticus and Ictalurus punctatus) and two native (Astyanax altiparanae and Prochilodus lineatus) fish species were offered as prey for these three predators in 300 L aquaria trials at three levels of habitat complexity. Salminus brasiliensis e B. orbignyanus showed greatest predatory efficiency at more and less complex habitats, respectively, whereas the habitat complexity did not affect prey consumption by P. corruscans. Cichla piquiti and O. niloticus were the invasive species most consumed by S. brasiliensis and P. corruscans, whilst I. punctatus by B. orbignyamus. The three species of native predators were potential controllers of some invasive fish species in the Paraná River Basin but, the consumption patterns differed for each predator according to their life history and the behavioural and morphological traits of the prey species. If, therefore, management actions for recovering these native predators populations will put in practice, they would be an interesting opportunity to test wether the results obtained from this work can be generalized to large scales.