French Polynesia and the Cook Islands this month created adjacent shark sanctuaries spanning 2.5 million square miles of ocean, a move that reflects a growing trend to protect sharks worldwide and more than doubles the area now off-limits to any shark fishing.

Blacktip Shark, Bora Bora, French Polynesia.

As many as a third of all shark species face some threat of extinction, according to the International Union for Conservation of Nature, in part because their fins are coveted for the Asian delicacy shark fin soup. In the last few months, American Samoa and the Micronesian state of Kosrae have barred shark fishing off their shores, and the European Union and Venezuela have both prohibited the practice of cutting off a shark’s fins while discarding the body at sea.

French Polynesia—a group of five major archipelagoes with more than 100 islands, including Tahiti—created the world’s largest shark sanctuary, banning fishing for all shark species in more than 1.5 million square miles of ocean on Dec. 6. The Cook Islands designated its own, which is equal to the size of Mexico at 756,000 square miles, on Dec. 12.

Oceanic whitetip (Photo: Tahiti Private Expeditions)

French Polynesia had established a moratorium on shark fishing and finning in 2006, but exempted mako sharks to win over local fishing interests. More than 20 shark species, including hammerhead and thresher sharks, swim off its shores.

Before French Polynesia’s declaration, six countries—Palau, Maldives, Honduras, Bahamas, Marshall Islands and Tokelau—had created shark sanctuaries.

Shout out: wildlifeextra.com