Bottom trawling on the deep seabed destroys ancient cold-water coral ecosystems and captures large quantities of deep-sea species as bycatch, with significant welfare implications.
Deep-sea trawling causes welfare harm at multiple levels. Individual fish and invertebrates are crushed, suffocated, or killed by barotrauma as they are rapidly brought from high-pressure depths to the surface. Bycatch of deep-sea species, many of which are long-lived and slow-reproducing, is caught and discarded dead or dying. The destruction of cold-water coral habitats eliminates entire ecosystems on which vast numbers of species depend for food and shelter. The scale and invisibility of these harms — occurring far from human observation at depths of hundreds of metres — has allowed the practice to continue largely unchecked.