Impact of Microplastic Ingestion on Commercial Fish: A Trophic-Level Analysis

Abstract Microplastic pollution represents a growing threat to marine ecosystems, with potentially adverse impacts on the health of aquatic organisms, including fish. The present study investigated the relationship between the ingestion of microplastics and the biological characteristics of fish in estuaries of the bays of Tumaco and Buenaventura, Colombia, during the years 2020 and 2021, focusing on the Sciaenidae and Ariidae families. A total of 1652 fish were analyzed, covering 12 species of the Ariidae family and 28 of the Sciaenidae family, to determine the trophic level (TL) of each species and quantify the amount of microplastics ingested. The results revealed a significant positive correlation between TN and microplastic ingestion in both families (Ariidae: p = 0.0254; Sciaenidae: p = 0.0028), suggesting that fish at higher trophic levels tend to accumulate a greater amount of microplastics. Additionally, it was observed that fish that had ingested microplastics had lower condition factor (CF) values, which could indicate a negative impact on their health and development. These findings highlight the bioaccumulation of microplastics throughout the food chain and their potential detrimental effects on fish health, such as alterations in their growth. Microplastics can also act as vectors for toxic pollutants, which could exacerbate their harmful effects. Although it is hypothesized that fish could ingest microplastics due to the high availability of these contaminants in the environment and their possible confusion with natural prey, such as plankton and invertebrates, the precise origin of the identified microplastics could not be determined, despite having considered potential sources such as plastic waste and human activities. This study is distinguished from previous research by its specific geographic focus on the estuaries of the Colombian Pacific coast, a relatively understudied region for microplastic pollution compared to other areas. Additionally, it focuses on fish species from the families Sciaenidae and Ariidae, which are of great commercial importance to the region, making the findings particularly relevant to food security and the local economy. Furthermore, the study provides a detailed analysis of the bioaccumulation of microplastics at different trophic levels, allowing a better understanding of how these contaminants are transferred through the food chain and affect organisms at different levels. Together, these aspects make this study unique and contribute significantly to the understanding of the impacts of microplastics at the trophic level in tropical coastal ecosystems. Together, these aspects make this study unique and contribute significantly to the understanding of the impacts of microplastics at the trophic level in tropical coastal ecosystems. The results highlight the need to further research the bioaccumulation of microplastics and their impacts at the population and ecosystem levels, in order to develop effective management and conservation strategies to protect the health of marine ecosystems. Graphic Abstract