The scars of bottom trawling on underwater mountains off Chile's coast are not healing, even decades after the fishing stopped. A recent study of seamounts in the southeastern Pacific found that the cold-water coral communities and other seafloor life remain severely degraded, with little sign of natural recovery. The findings challenge the assumption that marine protected areas alone can restore deep-sea ecosystems damaged by heavy fishing gear.
A Slow-Motion Recovery That Never Came
Researchers surveyed several seamounts in the Juan Fernández and Nazca-Desventuradas marine parks, which were closed to bottom trawling years ago. Using underwater cameras and remotely operated vehicles, they compared areas that had been heavily trawled with those that had escaped the worst damage. The difference was stark: on trawled seamounts, coral rubble and bare rock dominated, while untrawled peaks still hosted dense, living coral forests.
The team also measured the age of coral fragments and found that many of the broken pieces were decades old, meaning the damage happened long ago but the ecosystem has not bounced back. The slow growth rates of deep-sea corals, which can live for centuries, mean that full recovery could take hundreds of years, if it happens at all.
Why Local Fishers and Scientists Are Worried
The Juan Fernández Archipelago is home to a small but important fishing community that depends on the waters for their livelihood. The region's rock lobster fishery is world-renowned, and local fishers have long supported conservation measures, hoping that protected areas would help replenish fish stocks. But the new research suggests that the ecological damage from past trawling may have lasting effects on the entire food web, including the species that local people rely on.
Scientists are also concerned because seamounts are biodiversity hotspots, hosting species found nowhere else on Earth. The loss of coral habitat on these underwater peaks could mean the extinction of unknown or rare species before they are even discovered. The study's authors emphasize that preventing future damage is far more effective than trying to repair what has already been lost.
The findings serve as a cautionary tale for ocean management worldwide. As countries expand deep-sea mining and fishing, the slow recovery of Chile's seamounts shows that some marine wounds may be permanent. Protecting intact ecosystems, rather than assuming they can be restored later, is the only way to preserve the ocean's hidden richness.
