Microplastic Ingestion by Fish in a Neotropical Reservoir: Effects of Reservoir Dynamics and Fish Traits

Microplastic contamination poses a major threat in freshwaters, and rivers are considered sinks and pathways of plastic pollution to different ecosystems. Plastic abundance and concentration can be influenced by spatial factors, and artificial water bodies such as reservoirs can alter how plastics are distributed and interact with the biota. Additionally, biological traits like the trophic guilds and habitat use of animals can be important variables affecting plastic uptake. In this study, we investigated microplastic contamination in a fish community from a Neotropical reservoir. We assessed whether the distinct reservoir zones (fluvial, transitional, and lacustrine) had an influence on plastic ingestion by fish and also examined the effect of biological characteristics such as trophic guild and habitat use. Fibers and fragments of plastics were found in nine fish species and were identified as polyamide, polystyrene, and polyethylene. In general, plastic ingestion had a low incidence when compared to other reservoirs; however, we found that fish from the lacustrine zone, insectivores, and benthopelagic species showed a significant correlation with plastic ingestion. The findings presented here provide insights into the causes and the current state of microplastic pollution in Neotropical reservoirs.