This work consists of age, growth, and circuli formation period determination and the relation of reproduction, temperature, and pluviosity on the growth of S. intermedius Garavello & Britski, 1990. The growth curve was adjusted by the Bertalanfy's expression and the relationship between weight and size was made by the minimum square method to determine the conditioning factor. Gonadossomatic index (IGS) was used to study the reproduction. The assintotic values for length were 33,94 cm and 44,81 cm for males and females, respectively. The circulus were formed annually and the growth was slow and the maximum age was determined to be nine years. The formation of the circuli was influenced by the reproduction, probably allied to other abiotic factors like temperature and rain.
Schizodon intermedius; age; growth; Tibagi river