The Challenge of Microplastics in Aquatic Ecosystem: A Review of Current Consensus and Future Trends of the Effect on the Fish

In recent decades, the prevalence of plastics in the marine environment has increased and is amongst the most pervasive problems affecting the marine environment globally. Numerous studies have documented microplastic ingestion by marine species with more recent investigations focusing on the secondary impacts of microplastic ingestion on ecosystem processes. However, few studies so far have examined microplastic ingestion by mesopelagic fish which are one of the most abundant pelagic groups in the oceans and their vertical migrations are known to contribute significantly to the rapid transport of carbon and nutrients to the deep sea. Therefore, any ingestion of microplastics by mesopelagic fish may adversely affect this cycling and may aid in the transport of microplastics from surface waters to the deep-sea benthos. Microplastics are ubiquitous in the marine environment and are increasingly contaminating species in the marine ecosystem and the food chain, including food stuffs intended for human consumption. The effects of microplastics on aquatic organisms are currently the subject of intense research. Here, we provide a critical perspective on published studies of microplastic ingestion by aquatic biota. We summarize the available research on Microplastic presence, behavior, and effects on aquatic organisms monitored in the field and laboratory studies of the ecotoxicological consequences of microplastic ingestion. Finally, researchers plan further studies to learn more about how these fish are ingesting and spreading microplastics. It will be particularly interesting to see whether the fish ingest these microplastics directly as mistaken prey items, or whether they ingest them through eating prey species, which have previously ingested the microplastics. Also, there is a need to understand the mechanism of action and ecotoxicological effects of environmentally relevant concentrations of microplastics on aquatic organism health.