In contrast to marine organisms, the presence of microplastics (MPs) in freshwater animals remains insufficiently studied. The aim of this study was to identify the occurrence of MPs in the digestive tracts of two fish species from a small lowland river (Widawa R., SW Poland). In total, 202 gudgeons and 187 roaches were collected, of which 54.5% and 53.9% had ingested MP-like particles, respectively. Feeding type and behaviour, sex and capture site (above or below the dam reservoir) did not affect the number of fish with MP-like particles.
Keywords: Dam reservoir; Feeding type; Gobio gobio; Microplastics; Poland; Rutilus rutilus.