Idade e crescimento de Pterodoras granulosus (Valenciennes, 1833) (Siluriformes, Doradidae) no reservatório de Itaipu, Estado do Paraná, Brasil

Abstract

A total of 1033 individuals of Pterodoras granulosus (512 males and 521 females) were collected in Itaipu Reservoir. Individual age was estimated through the rings found in the vertebrae. In the period studied, the highest number of rings found was 10 for both sexes. The rings are annual and formed in November, as observed in time variation analysis of marginal increment, possibly resulted from the reproductive period beginning. The growth curve, expressed through Von Bertalanffy model, using the nonlinear procedure, is: Ls =48,57[1-e- 0,16(t+1,83) ] for males and Ls= 65,06[1-e-0,11(t+1,87) ] for females, in which the standard length is given in centimeters and the age in years