Crescer mais ou reproduzir primeiro? Análise de história de vida de três espécies de Osteichthyes do semiárido

Abstract

The study of the life history attributes directed to the growth and reproduction of semiarid animals may facilitate the understanding of how individuals remain in environmental conditions that influence their survival. The aim of this work was to analyze how occur the reproductive and somatic investment of Serrapinnus and Poecilia fish species in two hydroperiods of an intermittent stream, and to compare these investments not only interspecifically but also intra and intergenerally. Specimens of the species were collected in the Mundaú river basin to evaluate life history attributes related to growth (weight, length and relation between parameters) and reproduction (sex, stage of macroscopic and histological maturation and gonadosomatic relation). The reproduction of S. heterodon indicated to occur during the flood, while in the dry period the species invests in growth. The S. piaba species, as well as of the same genus, also showed to reproduce in the full river period, however invested in growth and somatic maintenance in both periods. Poecilia vivipara showed different results from those found for the two previous ones, with mature and pregnant females in both periods, with more fertilized females found in the dry season and more mature oocytes during the flood. Concerning to growth, P. vivipara indicated to invest more during the flood. It can also be observed that the females of the three analyzed species have a smaller maturation size than those found in the literature, and may indicate that the intermittent river environment selects individuals that anticipate their maturation size.