Ingestion of plastic and non-plastic microfibers by farmed gilthead sea bream (Sparus aurata) and common carp (Cyprinus carpio) at different life stages

Abstract Environmental pollution by plastic particles is of major global concern, as a potential threat to aquatic organisms and ecosystems. The accumulation of microplastics in freshwater and marine environments has strong ecological implications due to their long persistence, potential toxicity, and ability to adsorb other pollutants, acting as vectors of pathogens. Nevertheless, while the number of studies on the presence of microplastics in the wild fish increased, less attention has been paid to the farmed fish species. Here, we investigated the occurrence of microparticles in the digestive tracts of Sparus aurata and Cyprinus carpio at different life stages and reared by an intensive and semi-intensive production system, respectively. Our results showed the presence of natural microfibers and microplastics, with microfibers (~ 90%) being the dominant type. In both fish species, the presence of microparticles was not revealed at larval stage. Fry and adult S. aurata specimens showed microfiber abundances of 0.21 and 1.3 items/individual, respectively. A lower load of microparticles (p