▶ Watch Video: Shark researchers on the verge of unlocking great white mystery

Great white sharks are one of the most famous sea creatures, yet a key detail about their lives remains a mystery. For centuries, scientists have been unable to find where they mate in the Atlantic Ocean.

There are nine white shark populations around the world, and no one has ever identified a mating site, said Chris Fischer, founder and expedition leader of OCEARCH, a data-centric organization that safely tags and tracks sharks globally. 

“This is a 400 million-year-old secret,” he said. “The ocean’s not going to give it up easy.”

OCEARCH tagged its first Atlantic white shark in 2012. The team is on the verge of achieving their target of tagging 100 sharks and tracking them online. But before that, they hope to discover where the sharks mate.

Scientists think it might happen off the coast of the Carolinas during the summer migration, and to find out, they need blood samples. 

The team at OCEARCH operates with remarkable speed to install satellite tags on sharks, as they can only keep sharks out of the water for 15 minutes. During that time, they extract blood samples and conduct ultrasounds, all while the shark is awake and unsedated. 

During one recent shark capture off North Carolina’s Outer Banks, Brett McBride, captain of the OCEARCH science vessel, aided a shark’s breathing by pumping seawater through its gills. In a matter of minutes, the team collected data for 24 scientific projects from the same shark, which they named Umi, the Japanese term for ocean, and tagged her before she swam away. The tags will track the shark’s movements for the next decade. 

The great white shark population has been decreasing over the years due to overfishing, pollution and habitat loss. Conservation efforts aim to protect the iconic apex predators and their critical role in ocean ecosystems.

“They’re the system manager of the ocean. As they go, the ocean goes,” Fischer said. 

“The ocean is 70% of the planet and provides us two-thirds of our oxygen, 100% of our water and billions of people’s food every day,” Fischer said. “They are the guardians of our fish stocks. … There’s no future for us as humans if there’s not a robust future for our large sharks.”