Populational biology of Cyphocharax modesta (Hensel, 1869) (Characiformes, Curimatidae) in Lobo Reservoir, São Paulo State. I í Structure and growth

Abstract

The present work deals with the structure dynamics and growth of saguiru, Cyphocharax modesta (Hensel, 1869), collected in Lobo Reservoir (São Paulo) from April, 1993 to May, 1994. A predominance of males was observed during all the time of this study. Males and females occurs in the intermediary length and age classes. The growth curve was established by the annual ring method and the growth curve in weight was deducted from the mathematical expressions of the length growth curve and weight/length relation. The scales age rings formed yearly during the period of December to January. The growth is slow and the weight/length relation suggest that the weight is of the isometric type. The values of assintoctic length and weight found for both females and males are respectively 16.1 cm and 106.0 g and 14.8 cm and 83.0 g.