Reprodução e transferência energética para gônadas de três espécies de peixes em uma área de várzea na Amazônia Central

Abstract

The seasonality of water levels in Amazonian ecosystems strongly influences the life of aquatic organisms. Studies have shown that fish living in areas with large seasonal variations have differences in storage and allocation of energy reserves during the year. The patterns of energy allocation may change throughout fishes life spam as well as due to environmental variations. The purpose of this study was to describe the reproductive process and evaluate the dynamics of energy allocation to reproduction of three species of fish in a floodplain area in Central Amazonia. The specimens were captured, measured and weighed (body and liver), sexed, gonad development stages and the amount of fat were determined over a hydrological cycle. Fish size structure, sex ratio, mean length at sexual maturity, spawning period and type, fecundity and somatic indices were estimated according hydrological periods and maturitystages. Auchenipterichthys coracoideus is a multiple spawner and reproduces during the floodperiod. Mesonauta festivus is also a multiple spawner and reproduces throughout the year more intensively during the flood period. Psectrogaster rutiloides is a total spawner and reproduces during the dry period. The degree of cavitary fat was the best index to show the pattern of energy allocation to gonadal development for the three species, with a significant decrease during the breeding season, indicating the energy transfer from the cavity fat to the gonads. It was yet observed for M. festivus and P. rutiloides that females show a greater energy cost than males and adults have a larger fat reserve than the juveniles, indicating the importance of energy transfer from body reserve to gonadal development.