Microplastic ingestion in reared aquaculture fish: Biological responses to low-density polyethylene controlled diets in Sparus aurata*

During the last years, ingestion of microplastics (MPs) has been quantified in marine species both with an ecological and commercial interest at sea and under experimental conditions, highlighting the importance to assess MP ingestion in commercially and aquaculture important species such as gilthead seabream (Sparus aurata) fish. In order to study the ingestion of MPs in a commercially valuable species, gilthead seabreams were exposed to an enriched diet with virgin and weathered low-density polyethylene (LDPE) pellets for three months followed by a detoxification period of one month of no exposure to MP enriched diets. Our results indicate that MP ingestion in these fishes increased with exposure time, and differences were found between treatments, showing the highest ingestion values after three months of exposure to MP enriched diets and in the weathered treatment. However, after one month of detoxification, no MPs were found in the gastrointestinal tracts of fish, reflecting no long-term retention of MPs in Sparus aurata digestive system. According to results from this study, exposure of fish to MP enriched diets does not affect fish size neither the Fulton’s condition index as both parameters increased with time in all treatments (control, virgin and weathered). Both carbon and nitrogen isotopic signatures decreased with fish size in all treatments which could be related to an increase of nitrogen deposition efficiency in fish muscle with a high protein assimilation during the first months of Sparus aurata. © 2021 Elsevier Ltd. All rights reserved.

This study was funded by the Aquaculture derived plastics: Impacts and effects in marine food webs (ACUIPLASTIC) project from the National Program of Investigation, Development and Innovation orientated towards challenges of society from the Spanish Government (grant number CTM 2017-88332-R). The authors acknowledge financial support from the Spanish State Research Agency (AEI) and the Ministry of Science, Innovation and Universities (MICIU) to support the Thematic Network of Excellence (NET4SEA) on emerging contaminants in marine settings (CTM 2017-90890-REDT, MICIU/AEI/FEDER, EU). F. Alarcón from the Biology and Geology department of the Escuela Polítecnica Superior of the University of Almería for MPs enriched diet preparation. Authors want to acknowledge that M. Compa was supported by an FPI Fellowship from Conselleria d’Innovació, Recerca i Turisme of the regional Government of the Balearic Islands co-financed by the European Social Fund as part of the FSE 2014–2020 operational program. E. Álvarez was supported by a Personal Técnico de Apoyo contract (PTA 2015-10829-I) funded by the Spanish Ministry of Economy and Competitiveness. Authors want to thank the four anonymous reviewers for the constructive revision.

Peer reviewed