Las "palometas" o "pirañas" de las aguas del Paraná medio

Abstract

This paper deals with the species of the genus Serrasalmus of the middle and lower Parana River and related bodies of water. The authors give a revision of the literature referring to these species in that river pointing out that only three are known: Serrasalmus spilopleura (Kner), S. nattereri (Kner) and. S. marginatus (Valenciennes). Relative oeurrence, age and growth, feeding habits, reproduction and behavior under certain hydrobiological and climatic conditions are given. The paper also gives some data on winter mortalities during years 1962 and 1966 concluding that temperature is one of the main factors which limit the "piranha" populations in the middle and lower Parana River.