Avaliação do período reprodutivo de peixes nativos de importância econômica em reservatório do semiárido brasileiro

Abstract

The closed season of the fish species is defined by law, by the Normative Ruling No. 48/2005, which aims to ensure the survival of the fish species at least during the initial phase of its development. This law is an important tool for the conservation of the native species of the São Francisco river basin, since the natural characteristics of the river have been modified with the construction of the hydroelectric, which generates potential negative impacts to the reproductive aspects of the fish. This research was aimed to characterize the reproduction of the curimatã (Prochilodus argenteus), curvina-bicuda (Pachyurus francisci), piranha (Pygocentrus piraya) and pirambeba (Serrasalmus brandtii) species and confirm the closed season, supporting information for a more adequate management of the species.The samples were collected monthly, between June/2013 and May/2014, together with the fishermen colonies of the towns of Petrolândia, Floresta, Itacuruba and Belém de São Francisco, in the State of Pernambuco. The maturational stages were observed and the reproductive intensity was measured based on the Reproductive Activity Index (RAI) of the species and the estimation of the GSI of females captured in the Itaparica reservoir. All species have a minimum of 50% recovery in the closed season, equivalent to two months of sexual maturation peaks. P. argenteus was the only species to show a significant difference (p = 0.000052) in the relationship between the GSI and the months throughout the year, with the reproductive peak from January to May, as well as a higher value of the RAI in January and February. P. francisci presented a reproductive peak with intense reproductive activity (10<RAI≤20), and P. piraya and S. brandtii presented from a moderate to an intense degree of development of the ovaries in most months of the year. As for the environmental aspects, the precipitation had a positive relationship mainly with P. piraya and S. brandtii and the inflow showed a negative relationship with P. argenteus for the maximum GSI (p= -0.873), for the average GSI (p= -0.918) and the RAI (p= -0.909). Therefore, we can confirm that the closed season has played an important role in the conservation of the native species studied in the Itaparica reservoir, but it is necessary to monitor the changes in the environmental factors since they have a direct relationship with the reproductive peak of the species.