Fishing fleets are altering the seafloor much like farmer's ploughs have altered the landscape, indicates a study of the effects of so-called bottom trawling on the continental slope off the Spanish Mediterranean coast.
Bottom trawlers drag nets and gear to capture fish, shrimp and other marine life along the seafloor, and previous research has called out this technique for stirring up sediment and destroying habitat.
This new study by a Spanish team looked down into deeper waters than typically studied, at the upper portion of the continental slope, which drops out toward the deep ocean and offers insight into how the deep-sea landscape changes.
Bottom trawlers fish down to 2,625 feet (800 meters) in the northern Catalan margin, a region that contains La Fonera Canyon the focus of the new study.
They found that ship navigation tracks coincided with a smooth and homogenous seafloor, while untrawled areas had a complex surface. The smoothing out of the ocean bottom, the researchers note, eliminates variation in habitats, potentially reducing species diversity.