Establishment of non-native predator (Pisces, Erythrinidae) in a tributary of the Upper Paraná River basin, south Brazil

Erythrinus erythrinus is an erythrinid native from the basins of the Amazon, Orinoco, coastal rivers of the Guyana and Lower Parana, but allochthonous of Tibagi River region, Paranapanema basin. In the present work, we report the occurrence of E. erythrinus in Agua dos Tigres and Taquari rivers, in the Paranapanema basin, and aim to verify the occurrence of constancy and the condition of health of its specimens in sub-tributaries of the Lower Paranapanema River. The catch-per-unit-effort of the Agua dos Tigres River mouth was about three times higher than the site upstream of the same river, and the Taquari River presented the lowest value. The species presented constancy of catches in tributaries of the basin, where isometric growth and good health condition of the specimens were observed. Its introduction into the Tibagi River basin may have occurred due to an intentional release as remaining live bait discarded in commercial fishery operations or may have dispersed after the flood of the Sete Quedas Falls. The presence of juveniles along with adults indicates that the species is undergoing an establishment stage of the invasion process in the region. Keywords: Tibagi River, biological invasion, fishes, diversity loss.