Estimation of the age and biometry of Salminus brasiliensis (Cuvier 1816) captured in the Funil hydroelectric plants

Abstract

In order to better understand the ecology and biology of Salminus brasiliensis, and to provide basic information for the evaluation of fish stocks, this study verified the age and biometry S. brasiliensis. Sixty-six fish (aged 2-15 years) were captured at the Funil Hydroelectric Power Plant, Brazil, between September 2006 and August 2007. The biometric data recorded were weight, total and standard length, height, thickness and head length. Sex was determined by macroscopic evaluation of gonads. The gonads and liver were removed and weighed for calculation of gonadosomatic index and hepatosomatic index. The age of each fish was determined by analysis of growth rings in the scales, while the scale radius was measured from the focus to the end of the scale. Differences between seasonal biometric averages and reproductive indexes were verified using the Newman Keuls test at 5%. Results indicate that in the spring and summer seasons, smaller fish were caught compared to those caught during the winter and autumn. Females tend to have greater weight and morphometric measurements than males. The age and radius of the scale were positively correlated with the biometric variables. The biometric variables of S. brasiliensis can be used as an indicator of age in this species.