Bottom trawling pulls in roughly 19 million metric tons of seafood a year, about a quarter of the world's wild marine catch, but it also scrapes the seafloor and damages slow-growing corals and sponges. A single pass of bottom contact gear reduces seafloor invertebrate abundance by an average of 26 percent, according to a 2018 meta-analysis. The story also connects trawling to climate. Seafloor sediment holds the largest reservoir of carbon on Earth, and trawling stirs it up, exposing organic matter that can convert to CO2. A 2024 modeling study estimates 55 to 60 percent of that CO2 reaches the atmosphere within a decade, and total emissions could be up to twice the fuel emissions from the world's fishing fleets. For anyone tracking carbon markets or ocean policy, this is worth reading because it links a fisheries management issue to the carbon cycle. Bycatch, habitat loss, and seabed carbon all point toward the same need: treating the ocean floor as a climate asset, not just a harvest zone.
