In the present study it was examined the age and growth of Gymnogeophagus lacustris Reis & Malabarba, 1988 in Caconde lagoon (Tramandaí River Basin). The specimens (1080 males and 267 females) were collected monthly, between July 1992 and June 1993. The growth curve in total length was obtained by von Bettalanffy expression and the weight curve through the dedutive method supported by the mathematical expressions of the length growth curve and the length/weight relationship. Formation of the annulli in scales ocurred between winter and spring, and the first anual ring appears when the animals are aproximately 1.5 years old. L∞ and W∞ obtained for males and females, were 206.6mm and 157.3g and 120.2mm and 30.2g, respectively, demonstrating a characteristic sexual dimorfism for the species.
Gymnogeophagus; growth; coastal lagoon; Rio Grande do Sul; Brazil