Avaliação do conteúdo estomacal de peixes capturados no Baixo São Francisco

Abstract

This research was carried out during the II Scientific Expedition of the lower São Francisco, on the São Francisco River between the municipalities of Piranhas and Piaçabuçu, in the State of Alagoas, in November 2019, and aimed to verify qualitative and quantitative variations of the species of fish and food resources consumed. Sampling and collections were carried out in the lower course of the river (lower São Francisco), where they were derived from points along the flow of the river extension, where collection was made daily, at different times, in the daytime, during the period from vessel, the fish were collected with cast nets, sieves and trawl nets. In each stretch of collection of food items, qualitative and quantitative comparisons of occurrence percentages and weights per species and in the total number of fish were performed. Fish stomachs were propagated by collection point and species, totaling 113 specimens. Some species were found only at one of the collection points, while other species were sampled in small numbers. For the analysis of the stomach content, the volumetric frequency, the presence of the food item and the filling index were determined. The species evaluated had the greatest socioeconomic importance for the region and riverside population of the São Francisco River. The species with the highest number of species sampled was the pacu, although it was a type in which a higher retention rate of 0% was also verified, which may be due to the increase in river flow during the period of the expedition, as in others where it was possible to observe and analyze the stomach content, it was verified the strong presence of phytoplankton in the form of algae in its composition, however, it was also possible to observe that the stomach content was also influenced by the place where the fish were caught.

Keywords: Aquaculture; Fish; San Francisco.