Estructura del Ictiopláncton del Embalse Yacyretá en Diferentes Etapas del llenado a Cota Definitiva

摘要

The aim of this study was to analyze the structure of ichthyoplankton in two places in the Parana river upstreamthe Yacyretá dam during three phases in the waterline filling. Data comes from fortnight collections in two stationsfor active filtering network 100 m3 with 500 microns and fixed with 4% formaldehyde. In the reservoir, 6 orders and17 species were recognized, while in the sub damp 7 orders and 35 species were recognized. The most abundantspecies were Bryconamericus stramineus and Plagioscion ternetzi in the sub damp and Lycengraulis grossidensand Prochilodus lineatus in the reservoir. Preflexion stage was the most frequent in both places. Statistical analysisof the differences in terms of richness and abundance showed significant variations just between reproductivecycles, not between levels. Spawning and growth of early ontogenetic stages zones and feeding and growth zoneswere recognized for different species with high reproductive success in modified environments .