Presença de microplástico no trato gastrointestinal de Astyanax lacustris (PISCES, CHARACIDAE) na Bacia do Médio Uruguai, RS, Brasil

Abstract

Plastic products are increasingly available in our country, high consumption and globalization emphasize this production, microplastic has become a serious contaminant for our ecosystem. Synthetic fibers are ubiquitous in aquatic environments and can potentially be consumed by fish, although little is known about the consumption of this material by fish in freshwater systems. In this sense, the objective of this work is to evaluate the feeding of the species Astyanax lacustris and to verify the presence of microplastic in the gastrointestinal content. The samples were collected at six sample sites located in the Middle Uruguay river basin, three of them present in the main river: Alecrim, Porto Vera Cruz and São Borja and three located in the lower region of three tributaries: Ijuí, Icamaquã and Ibicuí. For the collection were used gillnets of different sizes and net. The captured organisms were immediately frozen and taken to the laboratory. A total of 229 digestive tracts were analyzed, 30 of them for food content analysis and 199 for microplastic (MP) identification. Occurrences of occurrence (FO%) and volume (V) and food index (IAi) were calculated for each food item found in the gastrointestinal content. The main items were allochthonous and autochthonous insects with more than 70% and 60% of FO%, respectively. Followed by other food items such as algae, fish and plant material, characterized as omnivorous with a tendency to insectivory. The MP analyzes indicated that all the sites present microplastic in the intestinal spent content of the fish, and the fish from the Ijuí (40.9%) and PVC (39.5%) sites presented the highest percentages of this pollutant. It is concluded that Astyanax lacustris is an omnivorous fish that is ingesting microplastics throughout the basin of the middle Uruguay river.