Ghost nets are abandoned, lost, or discarded fishing nets that continue to float in oceans, posing significant threats to marine life and ecosystems. They can entangle a wide range of marine animals, leading to injury, suffocation, and death. To prevent continuous wildlife by-catch, the Society for the Rescue of Dolphins coordinates complex ghost net retrieval operations several times per year on the German island Ruegen. Therein, teams of divers descend up to 30 meters (100 feet) into murky, dark, cold waters to attach lift bags to the ghost nets. The lift bags are then inflated, so that the net can safely float to the surface, where it is pulled out onto a fishing vessel and later discarded.