Reproductive and nutritional dynamics of Salminus maxillosus Valenciennes, 1849 (Pisces, Characidae) at Mogi Guacu River, Sao Paulo State, Brazil

The reproductive and nutritional dynamics of Salminus maxillosus were studied in 327 specimens (195 females and 132 males) collected in the Mogi Guacu River, Sao Paulo, Brazil from August, 1996 to July, 1997. Reproductive dynamics were assessed through analysis of monthly variation in gonadosomatic index, hepatosomatic index, relative frequencies of gonadal maturity stages and first sexual maturation size. Reproduction occurred from November to January (the highest values recorded in December), When the highest water temperatures and pluviometric index were observed. The size of S. maxillosus at first sexual maturation (Lpm) was calculated to be 346.7 mm (males) and 447.4 mm (females), the age being two years for both males and females. The L sub(100) values calculated were 525.0 mm for males and 625.0 mm for females, respectively. The nutritional dynamics were estimated through analysis of the monthly variation and the relative frequency of the repletion stages. S. maxillosus from Mogi Guacu River is in its optimum feeding condition before and during the reproductive season.