Primeros estadios del ciclo de vida de peces nativos del Río San Pedro (Cuenca del Rio Valdivia, Chile)

eggs, larvae and juveniles stages of the chilean native freshwater fish are practically unknown. to know their seasonality, morphology and habitat use is relevant to understand their biology and to allow the conservation of this highly threatened ichthyofauna. likewise, the early stages of fish's life cycle are highly labile and their success determines the persistence of the populations over time. for this reason the aims of this work is to report and describe the results of intensive samplings performed to find the early stages of the 14 native species that inhabit in the san pedro river (valdivia river basin). samplings were done during 465 days along the river, from october 2005 to march 2008. we found eggs, larvae and juveniles of galaxias maculatus, basilichthys australis and percilia gillissi, larvae and juveniles of geotria australis and trichomycterus areolatus; and juveniles only of diplomystes camposensis, percichthys trucha and cheirodon australe. we describe the season and habitat of occurrence, as well as their general morphological characteristics. this is the first description of embryonic and larval development stages for p. gillissi. a spatial-temporal segregation of the spawning and larvae rearing is observed, mainly marked by the use of the floodplain as rearing sites. the temporal extention of this study at riparian scale suggests than efforts in search of early stages of knowless species would be focus in deeper and/or rushing environments.