Growth curve estimated through scale age rings and length of gonadal first maturation of Astyanax schubarti Britski, 1964 (Pisces, Osteichthyes, Characidae), in Ibitinga Reservoir, São Paulo State, Brazil

Abstract

For determining Astyanax schubarti Britski, 1964 growth curve, scales rings were examined according to WERDER and SOARES (1984) method. The scales (65) located on the area beneath dorsal fin were found to be the best for lecture. The relationship between age and body total length, of which the estimation was done by von Bertalanffy (1938) method, were found to be: 1st year - 82.66 mm; 2nd year - 105.97 mm and 3rd year - 123.68 mm, in males; 1st year - 75.66 mm; 2nd year - 102.88 mm; 3rd year - 124.19 mm; 4th year - 140.88 mm and 5th year - 153.94 mm, in females. Mean body total length during first gonadal maturation, when fishes are about two years old, was found to be 83.3 mm in males and 95.0 mm in females.