Ictiofauna de Sierra de la Ventana y Chasicó (provincia de Buenos Aires. Argentina)

Abstract

This paper is directed to obtain some precision on the south western extension of the parano platense ichthyofauna in the Buenos Aires province. With such an aim, two trips were made (november 1979, april 1983) sampling 24 localities in Sierra de la Ventana and Chasicó lagoon neighborhood. Material was obtained with hand nets and moderate amounts oí “Pronoxfish”. Water samples were untamed, ana analised later according to the “Standard metnods for examination of water and wastewater”. Other parameters were obtained with an “Horiba U 7” analizer. New localities are reported for Bryconamericus iheringi (Siena de la Ventana), Rhamdia sapo (Sierra de la Ventana, Pelicurá and Chasico creeks) and Pimclodella la tic fps and Corydons pa lea rus (Sierra de la Ventana and Chasicó creek). These findings support Ringuelet hipothesis (1971, 1975) and extend beyond Sierra de la Ventana the south western border of the paranopiatense ichthyofauna. The pH values at the sampled environments are higher and more variable than in the middle Parana river; conducts vity less than in Central Argentina, and dissolved (h values high. Low amounts of principal ions were registered comparing with Córdoba environments. Mg/Ca ratio (0.29 to 0.55) and COD values are under those from the pampasic lagoons.