A comunidade de peixes dos reservatórios dos trechos médio e baixo do rio Tietê, com ênfase nas espécies introduzidas Plagioscion squamosissimus e Geophagus surinamensis
Abstract
From sixties, the fish species
introduction has been being a constant event in the reservoir system located on middle
and low Tietê River - SP, which resulted the success introduction of Plagiosicon
squamosissimus and Cichla cf. ocellaris in all these reservoirs. According to this
context, the present work objectified characterize the fish community, with focus on the
introduction analysis of Geophagus surinamensis, a not-native specie, and its probable
progressive occupation in the system, like that already had occurred with Plagioscion
squamosissimus. The results showed the occurrence of Geophagus surinamensis is
confirmed in these reservoir system, indicating that its fast occupation in the Três
Irmãos reservoir is made possible by the free connection that Pereira Barreto provides
between Três Irmãos reservoir and Ilha Solteira reservoir, on the Paraná River. This
way, it is evident the great possibility that the Geophagus surinamensis comes to be
disperse for the whole reservoir system of middle and low Tietê River, like that already
had occurred for the Plagioscion squamosissimus. Then, it is important to consider the
Geophagus surinamensis in management programs for the Três Irmãos reservoir, so as
to control and to reduce its density and of avoiding its effective spread for the others
reservoirs of Tietê River.