“Fish normally keep jellyfish in check through competition and predation but overfishing can destroy that balance. For example, off Namibia, intense fishing has decimated sardine stocks and jellyfish have replaced them as the dominant species,” says University of Queensland scientist, Dr Anthony Richardson.
Researchers describe the bizarre "Swima worms" in Science journal.
The creatures, which the scientists say could be widespread in the deep sea, indicate the extent of biodiversity yet to be discovered in the oceans.
Lead author Karen Osborn, from the University of California San Diego, told BBC News that she and her colleagues found the worms accidentally, whilst exploring the deep oceans with remotely operated submersible vehicles.
The gazetting of the proposal followed a five years process during which a scientific plan and a draft management plan were developed in collaboration with other role players.