Chile's Juan Fernández seamounts show no recovery 20 years after trawl ban
Two decades after Chile prohibited bottom trawling in the Juan Fernández Archipelago's seamounts, the ecosystems still exhibit no signs of recovery. Scientific research published in Deep-Sea Research Part I in June 2026 reveals that trawled areas bear visible scars from fishing gear, have sparse coverage of ancient habitat-forming corals, and reduced species richness and diversity. The study, led by Ignacio Petit of Oceana Chile and ESMOI at Universidad Católica del Norte, utilized data from a 2024 expedition using the ROV SuBastian on the R/V Falkor (too) from the Schmidt Ocean Institute. Researchers compared three seamounts in Juan Fernández (JF1, JF2, and JF6) with Solito, an untouched seamount, using historical trawling data from Chile's IFOP. Felipe Paredes, Marine Policy Director at Oceana Chile, stated that the study provides robust scientific evidence of long-term, real impacts on these fragile ecosystems. Javier Sellanes, an ESMOI researcher and expedition leader, noted the stark contrast between the simple systems in trawled areas and the complex coral structures observed in Solito. The study highlights that seamounts, characterized by slow-growing, ancient cold-water corals and high endemism, are highly vulnerable to disturbances like bottom trawling. The fishing activity, targeting orange roughy and alfonsino, occurred from 1999 to 2006, ceasing due to low catch rates after over 500 kilometers of seafloor were trawled. In 2012, Chile banned bottom trawling in 117 seamounts within its Exclusive Economic Zone, though Solito was not included due to its then-undocumented status. The research indicates that trawling nets, described as sea plows, cause significant damage, leaving rocky substrates scarred. JF2 was the most heavily impacted seamount, with 30 affected quadrants, followed by JF1. In contrast, Solito showed lower soft sediment coverage, more live habitat-forming coral, and evidence of natural coral mortality in the absence of mechanical damage. The study also observed differences in biodiversity, with Solito exhibiting higher coral, sponge, and crustacean abundance, including commercially valuable species, suggesting that seamount conservation supports artisanal fisheries. However, echinoderms, particularly the sea urchin Dermechinus horridus, were more abundant in trawled areas, potentially feeding on coral and further delaying ecosystem recovery.
This study underscores the profound and persistent ecological damage caused by bottom trawling, even decades after its prohibition. The findings highlight the inherent fragility and slow recovery rates of deep-sea seamount ecosystems, which are critical for biodiversity and potentially support fisheries. The research challenges the assumption that disturbed habitats will naturally rebound, suggesting that ongoing ecological processes, such as grazing by certain species, can impede recovery. This raises systemic questions about the long-term efficacy of conservation measures and the need for proactive restoration strategies, especially for slow-growing, ancient organisms. In the context of increasing pressures on marine environments, understanding these long-term impacts is crucial for sustainable ocean management and ensuring the resilience of these unique habitats against future anthropogenic disturbances.
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