An extensive new analysis reports that roughly one out of every three fish living in remote Pacific Island coastal waters contains microplastics. The findings, published today (January 28, 2026) in the open-access journal PLOS One, were led by Jasha Dehm of the University of the South Pacific and reveal especially high contamination levels in Fiji.

Microplastics are now recognized as a global environmental threat, affecting marine ecosystems and raising concerns about human health. Although Pacific Island Countries and Territories (PICTs) are often viewed as isolated, researchers say these regions may face heightened exposure due to rapid urban growth and limited waste and water treatment infrastructure. Fish play a central role in local diets, livelihoods, and cultural traditions, meaning plastic contamination could have direct consequences for many coastal communities. Until now, however, little research had examined microplastics in fish commonly eaten across the PICTs.

Large Study Examines Fish Across Four Pacific Nations

To fill that gap, the research team analyzed existing biodiversity data covering 878 coastal fish from 138 species caught by fishing communities in Fiji, Tonga, Tuvalu, and Vanuatu. The data were drawn from the Global Information Biodiversity Facility. Overall, about a third of the fish examined contained at least one microplastic particle, though contamination levels varied sharply by location.

Fiji stood out with nearly 75% of sampled fish containing microplastics, well above the global average of 49%. Despite this high frequency, the actual amount of plastic found in individual fish was generally low. At the other end of the spectrum, only about 5% of fish sampled in Vanuatu showed signs of microplastic contamination. While each island nation supports different fish populations, two species appeared in catches from all four countries — the thumbprint emperor (Lethrinus harak) and the dash-and-dot goatfish (Parupeneus barberinus) — and both showed higher contamination levels in Fiji than elsewhere.

Why Some Fish Are More Likely to Contain Plastic

The researchers also examined how a fish’s ecological traits influenced its likelihood of ingesting microplastics. Using a global database of fish species, they analyzed factors such as diet, feeding behavior, and habitat. Reef-associated and bottom-dwelling fish were found to contain microplastics more often than species living in lagoons, coastal waters, or the open ocean.

Fish that feed on invertebrates, forage along the seafloor, or rely on ambush strategies to capture prey were also more likely to ingest plastic particles. These patterns suggest that where and how fish feed plays a major role in determining their exposure to microplastics.

Implications for Food Security and Policy

According to the authors, the results demonstrate that microplastic pollution has reached even the most remote marine environments on Earth. Fiji’s particularly high contamination levels may reflect higher population density, extensive coastal development, and less effective waste management compared with other Pacific islands. Understanding how ecological traits shape exposure risk could help policymakers identify which ecosystems and communities face the greatest threats.

Jasha Dehm adds: “The consistent pattern of high contamination in reef-associated species across borders confirms ecological traits as key exposure predictors, while national disparities highlight the failure of current waste management systems, or lack thereof to protect even remote island ecosystems.”

Dr. Amanda Ford adds: “While microplastic levels in Pacific fish are generally lower than in many industrialised regions, Pacific communities rely far more heavily on fish as a primary protein source. Combined with major data gaps across the region, this makes locally generated evidence essential as Global Plastics Treaty negotiations advance and are translated into national policies.”

A Warning for Pacific Food Systems

Dr. Rufino Varea adds: “Beyond the ecological insights, this study delivers a stark warning about the vulnerability of our food systems: we found that the reef-associated and bottom-feeding fish most accessible to our subsistence fishers are acting as reservoirs for synthetic pollution, particularly in Fiji, where nearly three-quarters of sampled individuals contained microplastics. The dominance of fibers in these samples challenges the assumption that marine litter is solely a visible, coastal management issue; it indicates a pervasive infiltration of textile and gear-derived contaminants into the very diet of our communities.

“This data shatters the illusion that our remoteness offers protection and provides the evidentiary basis we need to reject downstream solutions—such as recycling schemes—as insufficient. Instead, it compels us to demand a Global Plastics Treaty that enforces strict caps on primary plastic production and toxic additives, as this is the only viable way to safeguard the health and food security of Pacific peoples.”