In addition, travelling through the reef provides ships with shallower and protected waters that allow them to anchor in the case of mechanical failure, making it safer than going around the reef into open sea and deeper waters.

FORBES: Providing Safe Passage: For Business And For The Great Barrier Reef

This means he can now tell legally caught Brazilian sand tiger sharks from those protected in American waters, and can catch fibbing fishermen.

ECONOMIST: DNA tracking

Fiji wants 30% of its waters protected and European nations including the UK are slowly imposing their own marine protected zones, prompted by the UN Convention on Biodiversity (CBD) which was initiated at Rio.

BBC: Shortages: Fish on the slide

The Welsh government looks after the marine environment and said it is aiming to have a small number of highly protected marine conservation zones in Welsh waters.

BBC: Sion Williams

Five years ago, the National Marine Fisheries Service instituted a fishery management plan to prevent overfishing of sharks in federal waters but the sharks aren't seeing the lines, apparently, and move in and out of federal waters and get caught in state waters where they aren't protected.

CNN: Humans the biggest threat to marine species