Idade e crescimento em peixes : da ciência de base à modelagem populacional.

Abstract

In this thesis we sought to understand the state of the art of the studies of age and growth in freshwater fish in South America and to expand the frontiers of knowledge for the use of calcified structures in an innovative way in the studies of age and for the use of models that explicitly consider characteristics of the life history. Thus, we tried to answer three questions: what is the coverage of studies of age and growth in freshwater fish in South America? Is it possible to predict the age from the morphometry of otoliths of freshwater fish, and thus facilitate studies of age and growth? What is the potential use of biphasic growth models to model the growth of freshwater fish? In the first approach a general review of the age and growth of freshwater fishes carried out in South America is made, explaining both places where studies are concentrated and where they are scarce. It was found that some species have clear differences in the maximum length and the speed of growth according to the place of occurrence. In the second approach, a case study was carried out on how the morphometry of otoliths can be used to predict characteristics using the otoliths of Prochilodus lineatus. The length of the otolith explains 85% of the variation of the individual's weight, but the age can not be distinguished from the morphometric characteristics of the otolith. In the third approach, the biphasic models of Lester and Quince-Boukal were used to model the growth of Prochilodus lineatus. The Lester model separates the growth of juveniles and adults and the Quince-Boukal models the growth of juveniles and adults simultaneously incorporating a transition related to energy investment and additionally allows to incorporate variations in the metabolic strategy through the parameter ? which is an exponent that describes how the energy available for growth/reproduction is related to mass variation.