The leatherback turtles feed on jellyfish so they bring the balance - if they are not there, it means there will be a jellyfish explosion and that will not be good for the whole functioning of the marine environment."
VOA: standard.2010.07.15
Leatherbackturtles weigh around 600kg (95st) and their shells can be up to two metres (6ft 7in) long.
One study in 2004 estimated leatherbackturtles had only a 50 percent chance of avoiding being accidentally snared by a deep sea fishing line each year.