Microplastic ingestion by Mullus surmuletus Linnaeus, 1758 fish and its potential for causing oxidative stress

A total of 417 striped red mullet, Mullus surmuletus, were analyzed to study microplastic ingestion and livers of fish were assessed to study effects of microplastics. Nearly one third (27.30%) of the individuals were quantified to ingest microplastics although there was no evidence of oxidative stress or cellular damage in the liver of fish which had ingested microplastics. A small increase in the activity of glutathione S-transferase (GST) of M. surmuletus was detected which could be suggesting an induction of the detoxification systems but these findings should be tested in laboratory conditions under a controlled diet and known concentration of microplastics. Fish from trammel fisheries, operating closer to land and targeting larger individuals, showed higher mean ingestion values than fish from trawling fisheries, and were related to body size, as microplastics ingested increased with total fish length. Consequently, ingestion values of microplastics were not related to sampling distance from land giving further evidence of the ubiquity of microplastics in the marine environment. Finally, Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that the vast majority of microplastics were filament type and polyethylene terephthalate (PET) was the main identified component

This study was partially funded by the European Commission DG Environment project: “Support Mediterranean Member States towards coherent and Coordinated Implementation of the second phase of the MSFD – MEDCIS” with Grant no. 11.0661/2016/748067/SUB/ENV.C2. Sampling was carried out under PESCAMED CUATRO project, co-funded by the EU through the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy. Special thanks to V. Rubio and N. González for assistance throughout the biological sampling at the Spanish Institute of Oceanography (IEO), Balearic Centre of Oceanography (COB) and to A. Gascon, M. Compà and A. Garcia during sorting analyses. Acknowledgments to T. Gajst, T. Bizjak and A. Koistinen for the FTIR analyses at the University of Eastern Finland. A. Sureda was supported by the Programme of Promotion of Biomedical Research and Health Sciences CIBEROBN CB12/03/30038. The authors hereby acknowledge the Ph.D. grant provided by the University of the Balearic Islands.

Peer reviewed