New study reveals extent of plastic pollution in Roatan’s mangrove forests

A newly released scientific paper, set to appear in the December 2025 issue of the Marine Pollution Bulletin, has revealed alarming levels of marine litter in the mangrove ecosystems of Roatan, Bay Islands, Honduras. The study — titled “Marine litter in mangrove soils of Roatan, Western Caribbean: Abundance, sources, and ingestion by an American crocodile (Crocodylus acutus)” — offers the first comprehensive baseline of solid waste contamination in the island’s protected mangrove zones.

The research was led by Zara Zúñiga-López of Carleton University and the Bay Islands Conservation Association (BICA), together with Lisa M. Erdle, Victoria M. Fulfer, Luis Flores, Gisselle Brady, and Jesse C. Vermaire. The collaborative work also involved scientists from The 5 Gyres Institute in California, a global leader in plastic pollution research.

A first look at the scale of mangrove pollution

Researchers surveyed four mangrove sites within the Bay Islands National Marine Park, collecting 3,417 pieces of litter from 20 sampling quadrats. They found an average concentration of 6.83 litter items per square meter, revealing a significant accumulation rate for a protected ecosystem.

A staggering 98.7% of all collected debris was plastic, underscoring the dominance of non-biodegradable waste in Roatán’s coastal environment. Only 2.4% of the litter had legible labels, most traced back to Honduras and Guatemala, suggesting that both local and regional waste management systems contribute to the problem.

Among plastic bottles with visible manufacturing dates, the average age was seven years, indicating that plastic waste persists in Roatán’s mangrove soils for nearly a decade before breaking down — if at all.

A disturbing finding: ingestion by wildlife

In a striking discovery, researchers also examined a deceased American crocodile (Crocodylus acutus) found near one of the study sites. The animal had ingested 62 separate pieces of litter, demonstrating the direct threat marine debris poses to native species in the Bay Islands.

This case marks the first documented instance of plastic ingestion by a crocodile in Honduras, highlighting the urgency of addressing waste pollution not just as an environmental issue, but as a biodiversity crisis.

The authors note that Caribbean mangroves remain underrepresented in global marine litter studies, despite being among the most important natural defenses against coastal erosion and storm surges. Roatán’s mangroves serve as nurseries for fish, protect shorelines, and store carbon — yet the buildup of long-lived plastics compromises these vital functions.

“The findings from Roatan help fill a critical data gap for the Caribbean,” the researchers write. “They provide a baseline that can guide conservation efforts and policy decisions for years to come.”

The paper also emphasizes the need for regional cooperation to tackle marine litter, given the evidence that floating plastics are crossing borders through ocean currents and trade routes. The Marine Pollution Bulletin is one of the world’s leading peer-reviewed journals in ocean science and conservation, publishing cutting-edge research on pollution and environmental impacts across marine ecosystems.

For Roatan, this research underscores a growing challenge: balancing tourism, development, and environmental protection. The Bay Islands Conservation Association has long advocated for improved waste collection systems and stricter enforcement of litter control laws, especially around mangrove and coastal areas. As the Bay Islands continue to grow in popularity as an ecotourism destination, studies like this serve as both a warning and a call to action — urging the community, authorities, and visitors alike to protect one of the Caribbean’s most fragile ecosystems.