Drifting tuna fishing devices reaching protected marine areas globally

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A new international study co-authored by a University of Hawaiʻi at Mānoa researcher found that drifting devices used by the global tuna fishing industry are entering marine protected areas around the world, creating potential risks for wildlife and sensitive ocean habitats.

The study, published on June 17 in Science Advances, analyzed publicly available data on drifting fish aggregating devices (dFADs)-floating rafts equipped with GPS technology that help commercial fishing fleets locate tuna. Researchers estimated the devices have likely drifted through more than half of the world's marine protected areas by total area.

The findings are especially relevant for Hawaiʻi and the broader Pacific, where vast marine protected areas coexist with some of the world's busiest tuna fishing grounds. Researchers found hotspots for dFAD interactions in the central Pacific, western Indian Ocean and Caribbean. They also documented at least 6,300 strandings of the devices in 174 protected areas across 53 maritime jurisdictions.

When these floating structures wash ashore or become trapped on reefs, they can damage coral, contribute to plastic pollution and entangle marine animals such as sea turtles and sharks. The study identified nearly 500 at-risk species living within protected areas where dFAD strandings have been observed.

John Lynham, a professor in the UH Mānoa Department of Economics and UHERO in the College of Social Sciences and a study co-author, said the research highlights an unintended consequence of modern tuna fishing technology.

"Marine protected areas are designed to safeguard ocean ecosystems, but drifting fishing devices do not recognize those boundaries," Lynham said. "Our findings show there is an opportunity for the fishing industry, governments and conservation groups to work together on practical solutions that better protect these important places."

The findings come as the future of marine protected areas has drawn renewed attention in the U.S. following President Donald Trump's decision to lift restrictions on commercial fishing in some marine national monuments. The study itself focuses on the broader issue of drifting fishing devices crossing protected boundaries regardless of whether fishing is allowed inside those areas.

The researchers emphasized that while the fishing industry has made progress by developing less harmful and more biodegradable devices, additional steps are needed. They recommend stronger regulations, greater transparency in tracking the devices and better systems to retrieve them before they become marine debris. The study also found that the burden of removing stranded devices often falls on local communities and marine managers, including those in small island nations that may not benefit economically from the fisheries responsible for the equipment.