Relação peso-comprimento para peixes de água doce no Brasil: uma meta-análise

Abstract

In this study, we analyzed the length-weight relationship of different freshwater fish species from Brazil, aiming to identify growth patterns and potential ecological adaptations. Through a meta-analysis, the allometric coefficients a and b were evaluated for 28 species. The results indicated that body shape and body size significantly influence growth patterns. Species with elongated and fusiform bodies, such as Acestrorhynchus microlepis, predominantly exhibited negative allometric or isometric growth. In contrast, species with robust or laterally compressed morphology, such as Serrasalmus rhombeus, showed a tendency toward positive allometric growth, characterized by a steeper increase in weight relative to length. Large-bodied fish, like S. rhombeus, displayed faster growth in body mass, whereas small-sized species, such as Corydoras paleatus, showed more proportional growth, reflecting distinct resource allocation strategies. Overall, piscivorous species exhibited larger body sizes, favored by a protein-rich diet with high energy content, resulting in positive allometric growth. On the other hand, herbivores, which consume food of lower caloric value and variable digestibility, tended to show near-isometric growth, highlighting an adaptation focused on efficient resource utilization. Additionally, parental care was associated with greater body development, as exemplified by Metynnis lippincottianus and A. microlepis. We conclude, therefore, that factors such as body shape, size, reproductive strategies, and diet type directly influence the a and b coefficients of the length-weight relationship. Large-bodied species with robust morphology tend to exhibit positive allometry, while smaller species approach isometry. Feeding strategy emerged as the most determining factor, with piscivores showing higher b values and detritivores presenting significant variations in the a coefficient, reinforcing the influence of ecological aspects on growth patterns.