As with the Marshall Islands' declaration, the Cook Islands' effort was with the help of the Pew Environment Group, which advocates island nations' involvement because of the vast scope of their territorial waters.

BBC: Cook Islands' shark sanctuary creates world's largest

Matt Rand, director of Global Shark Conservation for the Pew Environment Group said that this was the latest of a number of studies "confirming the importance of preserving the parts of the ocean where sharks breed and raise their pups".

BBC: Shark mums 'invest' in newborns

Dr Susan Lieberman from Pew Environment Group said it was a big day for the convention.

BBC: Cites meeting votes to protect Oceanic whitetip shark