Scientists are already warning that the oceans will suffer profound changes as a result of overfishing and destructive fishing practices.
Most fishing gear is not selective. This means that as well as the 'target' species of fish it catches, any number of 'non-target' species may also be hauled in. This 'incidental' catch of other species is referred to as 'bycatch'.
Globally, it is estimated that almost a quarter of what is caught is merely killed and discarded.
Bycatch is not limited to unwanted fish species. All types of marine life including whales, dolphins, porpoises, fur seals, albatrosses and turtles are killed as bycatch. For example, a staggering 100 million sharks are killed each year.
Tuna fisheries, which in the past had high dolphin bycatch levels, are still responsible for the deaths of 1 million sharks.