Assessment of the impact of microplastic ingestion in striped red mullets from an Eastern Mediterranean coastal area (Zakynthos Island, Ionian Sea)

Abstract

Monitoring microplastics (MPs) in the marine environment is an ongoing process, and our understanding of their impact on marine organisms is limited. The present study evaluates the effects of ingested MPs on the marine MP pollution bioindicator fish species Mullus surmuletus. The study follows a three-fold approach to assess the impact of MPs on marine organisms by investigating: 1) the ingestion of MPs, 2) the bioaccumulation of phthalate compounds as plastic additives, and 3) the evaluation of toxicological biochemical and cellular biomarkers. Striped red mullets were sampled in the marine protected area (MPA) of the National Marine Park of Zakynthos and coastal sites with high touristic pressure in Zakynthos Island in the Ionian Sea, Greece. Fewer ingested MPs and lower phthalate concentrations were found in fish inside the MPA compared to those sampled outside the marine park. However, no relationship was found between either phthalate concentrations or biomarker levels with the ingested MPs in the red striped mullets. Biomarker levels were influenced by season and site, but no effect could be attributed to the ingested MPs. The lack of association of biomarker responses and plasticizer bioaccumulation to MP ingestion can be explained by the low number of ingested MPs in the fish from Zakynthos coastal area as MP abundance ranged from 0.15 to 0.55 items per individual fish.