Marine life habitats are fragile and often damaged by fishing gear outfitted to drag along the seafloor. The right-hand image above shows the damage of a trawling net, outfitted to drag along the seafloor, targeting groundfish such as cod. Along the net's base are large rubber tires, called "rockhoppers," that allow the net to hop over any rocks, ledges or other structures along the seafloor without getting snagged. The effects on the seafloor are devastating. Vast expanses of ocean bottom have been stripped of their natural structures that fish and other marine life need for shelter, breeding, nursery grounds and feeding.