How Bottom Trawling is Destroying Earth’s Final Frontier
What if bulldozers were clearing ancient forests the size of San Francisco (47 square miles) every day—leveling everything from the historic buildings of Chinatown to the vibrant streets of the Mission District, from the towering redwoods of the Presidio to the protected wildlife areas of the Bay? The public outcry would be deafening. Now what if this destruction is happening daily, but underwater? Yet a similar devastation occurs daily beneath the waves, largely out of sight and mind. Bottom trawling—the practice of dragging heavy nets across the seafloor—is effectively clear-cutting the ocean’s ancient forests.
Like terrestrial deforestation, bottom trawling leaves lasting scars on ancient landscapes. Massive nets, weighted with heavy metal plates and chains, scrape across the seafloor to catch species like cod and rockfish. But in their wake, they leave behind a barren underwater desert.
Just as clear-cutting destroys more than just trees, bottom trawling’s destruction goes far beyond catching fish and over fishing. These heavy nets crush coral forests that have grown for centuries, overturn massive boulders that shelter marine life, and flatten complex underwater structures that took millennia to form. Repeated trawling can lead to long-lasting changes in seafloor habitats, affecting biodiversity and the health of marine ecosystems. For instance, slow-growing deep-sea corals like Lophelia pertusa, which provide habitat for diverse marine life, are particularly vulnerable to damage from trawling gear.
The recovery rates between forests and ocean floors reveal an even more sobering reality. While a clear-cut forest might show signs of recovery within 5-10 years and return to mature forest in 50-100 years, deep-sea ecosystems can take centuries or even millennia to recover—if they recover at all. Deep-sea coral gardens, which grow at rates of just millimeters per year, might need 1,000 years or more to recover after trawling damage.
And like rainforests, these deep-sea ecosystems are still largely mysterious to us. Scientists estimate we’ve explored less than 20% of the ocean floor, meaning we’re destroying underwater habitats before we even understand their full ecological importance. Recent discoveries highlight what we might lose: in 2020, scientists found gardens of glass sponges off the coast of Alaska that function as living fiber optic cables, transmitting light in the darkness of the deep. In 2019, researchers discovered a new species of giant amphipod in the Mariana Trench that could hold keys to surviving extreme pressure. Even more remarkably, in 2016, a deep-sea expedition found bacteria that could help in developing new antibiotics. Each pass of a trawling net could destroy similar undiscovered wonders.
Also, bottom trawling stirs up sediments, releasing stored carbon into the ocean and potentially into the atmosphere, contributing to carbon emissions. This mirrors how deforestation releases stored carbon from terrestrial ecosystems. A 2021 study estimated that bottom trawling could release as much as 600 and 1,500 million tons of CO₂ annually, comparable to the emissions of major industrialized nations.
In response to these environmental concerns, some countries have implemented regulations to limit bottom trawling. Much like the protected areas established to prevent deforestation, the United States has established closed areas to protect overfished species and sensitive habitats. In 2018, revisions allowed trawling in some previously closed areas while closing new sensitive habitats to bottom trawling. Similarly, the European Union and other nations have enacted measures to protect vulnerable marine ecosystems from the effects of bottom trawling.
Yet unlike deforestation, which often makes headlines and sparks public outrage, the destruction of ocean floors continues largely unnoticed. As we race to protect Earth’s remaining forests, we must also turn our attention to preserving these underwater wilderness areas before they’re lost forever. The ocean floor represents our planet’s last true frontier—and we’re destroying it before we’ve even fully explored its wonders.