Effect of biological and environmental factors on microplastic ingestion of commercial fish species.

Marine litter is an emerging pollution all over the world. In addition to the macro sized plastics, ongoing scientific efforts revealed risks of micro and nano sized plastic particles in marine environment. In the past decades, an increasing number of studies have been carried out to understand the dynamics of this pollution. The aim of the present study was to investigate the microplastic (MPs) ingestion in commercially important fish species and to evaluate biological and environmental factors influencing the ingestion status. Gastrointestinal tract content of a total of 2222 individuals belonging to 17 species were examined for MPs existence. Out of 17 species evaluated, 13 of them was detected to ingest MPs. Our results showed that 18.1% of investigated fishes ingested MPs and the average length of the detected particles was 1.26 ± 1.38 (±SD) mm. The most dominant MP type was fiber (90.1%), while the most common particle colours were black (46.9%) and blue (29.4%). Polypropylene (85%) was the most common polymer type detected. Our evaluations indicated that the exposure of fish distributed in coastal areas to microplastic pollution is corelated to physical (precipitation and distance to nearest shore) and biological (functional trophic group, habitat of the species) factors. In order to design a more effective control mechanism, these impacts should be included in the assessments in future practices to reveal the effects of microplastic pollution on biota.