Growth of the tambaqui Colossoma macropomum (Cuvier) (Characiformes: Characidae): which is the best model?

M A H Penna,M Petrere-Jr,T Walter,M A Villacorta-Corrêa

doi:10.1590/s1519-69842005000100017

Abstract

In order to decide which is the best growth model for the tambaqui Colossoma macropomum Cuvier, 1818, we utilized 249 and 256 length-at-age ring readings in otholiths and scales respectively, for the same sample of individuals. The Schnute model was utilized and it is concluded that the Von Bertalanffy model is the most adequate for these data, because it proved highly stable for the data set, and only slightly sensitive to the initial values of the estimated parameters. The phi values estimated from five different data sources presented a CV = 4.78%. The numerical discrepancies between these values are of not much concern due to the high negative correlation between k and Linfinity viz, so that when one of them increases, the other decreases and the final result in phi remains nearly unchanged.

Highlights

Classical fish stock management models rely heavily upon growth parameter estimates that if biased or based on inadequate model premises lead to wrong strategies
In this paper we critically examine its adequacy for describing the growth of the tambaqui Colossoma macropomum Cuvier, 1818, in the Central Amazon basin based on length-at-age data from otholiths and scales readings
The data were fitted by the generic equation of Schnute (Equation 3), using several combinations of the mean values of the datasets as initial values for γ and γ

Summary

Introduction

Classical fish stock management models rely heavily upon growth parameter estimates that if biased or based on inadequate model premises lead to wrong strategies. Since the classical von Bertalanffy growth model fits most of the length/weight-at-age data, it is adopted a priori. In this paper we critically examine its adequacy for describing the growth of the tambaqui Colossoma macropomum Cuvier, 1818, in the Central Amazon basin based on length-at-age data from otholiths and scales readings. The tambaqui is the largest characin of South America. It may reach more than 1 m in total length and 45 kg in total weight in a specimen observed at the Guaporé river, municipality of Costa Marques (RO), in 1989 by M. At present it is difficult to find individuals above 85 cm (20 kg) in the fish markets of the Central Amazon (Araújo-Lima & Goulding, 1997)

Objectives

Methods

Results

Conclusion