Industrial tuna fleets release them by the tens of thousands, and once they are in the water the currents take over — carrying the gear into reserves that no tuna vessel could legally enter. For the first time, a study in Science Advances has charted just how deep into protected waters drifting fish aggregating devices travel. dFADs, the floating rafts purse-seine crews use to draw tuna together, are turning up far beyond where anyone expected.
The team tracked 88,359 dFAD buoys. It found the rafts have likely reached 53% of the world's marine protected area network by area, washing up inside 174 reserves spread across 53 maritime jurisdictions — waters that are home to close to 500 at-risk species. At least 6,300 separate strandings were logged, clustered in the central Pacific, the western Indian Ocean and the Caribbean.
What makes it so hard to fix is jurisdiction. A marine park can refuse entry to a fishing boat at its edge, yet it has no power over a raft cut loose hundreds of kilometres offshore that simply rides the tide inside.
"Marine protected areas are designed to safeguard ocean ecosystems, but drifting fishing devices do not recognize those boundaries," said John Lynham, an economics professor at the University of Hawaiʻi at Mānoa who co-authored the paper.
The harm is physical. Lead author Laurenne Schiller, a marine conservation scientist at Carleton and Dalhousie universities, relayed what reserve staff had told her — that the rafts were "hitting corals and just shearing off large chunks of coral in many protected areas or getting stuck and … going back and forth and just breaking corals."
The Galápagos Marine Reserve is the clearest example. At least 277 FADs have been recorded drifting in since 2017, and officials say the true number is far higher. Inti Keith of the Charles Darwin Foundation said researchers regularly find sharks, turtles, sea lions, seabirds and other animals tangled in the mesh, or worse, dead.
Park staff are frank about how little they can control. "This modality of fishing … is not going to stop," said Leonardo García, a quality-control manager at the reserve's Isabela unit, who said the real job is getting the industry "aware that there's a responsibility to recover" the gear. Colleague Jenifer Suárez described the aim in simpler terms: "What we are trying to look for is a way to find out how to prevent these [FADs] from entering the reserve."
Industry representatives insist change is already happening. Guillermo Morán Velásquez, who heads the tuna group TUNACONS, said its intention is "to close the loop: to design better, recover more and recycle or reuse as much as possible." He resisted casting the devices as the culprit: "The problem is not the use of the FAD per se — it's gear that improves the efficiency of fishing." The group says it retrieved about 60 FADs across three years.
Critics are unconvinced. Alberto Andrade, who runs the conservation group Frente Insular, brushed the recovery efforts aside: "That idea of plantado recovery is just a greenwash."
Change is nonetheless coming from the regulators. Netting is now banned in dFADs across every tropical-tuna management body, the International Seafood Sustainability Foundation has tested a fully biodegradable "jelly FAD" made from bamboo and cotton, and from 2026 the Indian Ocean Tuna Commission will be the first to demand a registry linking each raft and buoy to the boat that set it adrift.
