In the most comprehensive review on this topic to date, the researchers discovered that 386 marine fish species have been found to ingest plastic debris, which includes 210 commercially significant species. This rise in plastic ingestion reports could be attributed to enhanced microplastic detection methods and the increasing plastic pollution in our oceans. The first documented case of animals consuming plastic was recorded in the stomach of a seabird in 1969, and reports of fish ingesting plastic off the coast of southern New England followed in 1972. Since then, numerous studies have observed plastic consumption in various fish species. However, each study contributed only a part of the larger picture, necessitating efforts to contextualize these findings comprehensively.
Their research forms part of the Oceans 21 series by The Conversation, which includes myriad global ocean profiles and articles leading up to international climate discussions. Savoca’s team compiled the most extensive database on marine fish plastic ingestion, synthesizing findings from scientific studies published between 1972 and 2019. They recorded details like the species examined, plastic content in fish, and the geographical regions with varying levels of pollution.
The study examined fish diets, habitats, and feeding actions to ascertain influencing factors for plastic ingestion. The results were unexpected and concerning, as marine fish worldwide were found with plastic in their systems. Out of 555 species studied, over two-thirds had ingested plastic. Their research shows that fish plastic consumption is on the rise, doubling across all species and reaching 33% in some studies conducted between 2017-2019, up from 15% in 2010-2013. This increase could partly be due to advanced methods now capable of detecting microplastics more easily, alongside growing global plastic pollution.
Despite alarming statistics, not all ocean fish consume plastic. Nearly a third of the studied species did not show plastic ingestion, and studies which did report plastic in fish didn’t find it in every individual. Typically, affected fish had only one or two pieces in their stomachs. The ingestion is influenced by the species’ environmental context, habitat, and dietary habits. Predatory fish like sharks, grouper, and tuna showed higher tendencies to consume plastic, particularly in regions like the Mediterranean and parts of East Asia known for significant plastic pollution.
This issue extends beyond wildlife conservation; the effects of plastic ingestion on fish and human health remain largely unexplored. Emerging evidence suggests that some microplastics and even smaller particles, known as nanoplastics, can move from fish stomachs to muscle tissue—the part humans frequently consume. Highlighting this, the study underscores the importance of further research into how plastics may transfer to humans and their potential implications.