Determination of growth curve throwgh scales lecture in different body regions of Astyanax bimaculatus (Linnaeus, 1758) (Pisces, Characidae), in Ibitinga reservoir, São Paulo State

Abstract

The counting of age rings in scales method was employed to determine growth curve for Astyanax bimaculatus in Ibitinga Reservoir (21°46'S and 48°59’W), according to von Bertalanffy, equation. 50 specimes, caught from July 1989 to June 1990 were analysed. It was also determined that the best body region for scales lecture, according to WERDER and SOARES ¹⁸ (1984), was surrounding the pectoral fin (E region). Observed results showed: - for 8 age classes, mean total lengths were: 1 - 61.03 mm; 2 - 75.30 mm; 3 - 86.67 mm; 4 - 97.92 mm; 5 - 109.80 mm; 6 - 121.75 mm; 7 - 134.13 mm and 8 - 144.40 mm. - The general growth curve equation estimated from the obtained data is: ^{^}Lt = 223,14 [1 – e ^{-0,1027 (t + 1,8549)} ]