Are Outer Banks shark gatherings part of brutal mating ritual? Expedition seeks proof

One of the many mysteries surrounding North Carolina’s Outer Banks is why the islands attract throngs of great white sharks this time of year, and a group of marine researchers has an unsettling theory.

This tourist’s paradise is also where the sharks gather to violently mate.

Circumstantial evidence supporting this idea has been building for years, but a first-of-its-kind expedition to find proof launches Friday from Brunswick, Georgia, destined for the Carolina coast.

OCEARCH, a nonprofit dedicated to white shark research, intends to capture as many sexually mature great white sharks as it can over 21 days and run blood tests for elevated hormone and sperm levels.

The team’s target zone is between Cape Lookout and the Frying Pan Shoals, a treacherous stretch of shipwreck-dotted coast known as the Graveyard of the Atlantic.

Even more challenging: The sharks they’ll be chasing are large (more than 12 feet), sexually charged and “determined” to mate, OCEARCH founder Chris Fischer told McClatchy News.

The countless risks are worth it, he says, because no one has found a mating ground for white sharks, an apex predator known to reach 20 feet in length.

“It doesn’t surprise us that the white shark is putting in us in difficult position to solve a 400 million-year-old puzzle of where they mate. Nothing they do has made it easy for any scientist over the course of the last many decades,” Fischer said. “If it was easy, it would have been done already.”

The expedition runs through April 1 and will include 42 scientists from 28 research institutions. Data will be collected off the sharks for 23 different science projects, including a study on how sharks react to being temporarily caught, OCEARCH says.

Why the Outer Banks?

A dangerous “confluence of currents” — warm and cold — collide off the Outer Banks, which is how the islands are formed and why hundreds of ships have been lost in the shoals over the past five centuries.

Fischer calls the coastline “brutal” and says the many dangers are a big reason why OCEARCH has conducted its 39 prior expeditions in other areas.

Process of elimination is a big reason researchers believe the Outer Banks is a mating site. Tests done on white sharks in other areas have not detected elevated hormones or sperm levels, Fischer says. And the timeline of shark pup births doesn’t match up to shark gatherings in the north or south.

Meanwhile, something unusual continues to happen off the Outer Banks: Sexually mature sharks are gathering here February through April, then the females head into the Mid-Atlantic with no clear destination, he says.

“They are moving off shore to gestate,” Fischer says, noting that’s still a theory. “We’ve had them go as far as the Mid-Atlantic Ridge and we believe they are moving there to lead a low-risk lifestyle on their own. No bumping into another male and no mating violently.”

It’s believed white shark mating involves the male grabbing the female by the head with its jaws, in an attempt to “roll her over,” Fischer says. Sometimes, more than one male is trying to do it at once, adding to the female’s elevated stress level, Fischer says.

The process leaves fresh scars on the females, and those scars have been found on white sharks in the Southeast. That’s yet another clue this is the right place to look, he says.

Satellite tags provide clues

OCEARCH has already learned much from tagging and tracking white sharks via satellite, including learning they use the East Coast as a kind of highway.

White sharks are currently moving south, a trek that will take them to the tip of Florida, the Caribbean or into the Gulf of Mexico. Come June, they’ll head north again, into the Northwest Atlantic off Canada, OCEARCH says.

A mating cycle that involves the Outer Banks would coincide with the Spring Equinox, Fischer says.

There are months when eight or more white sharks sporting OCEARCH tags have gathered off North Carolina, and Fischer says each one “represents hundreds of sharks” in the area.

Still, he is not overly optimistic the expedition will easily find what it’s looking for this month. It could take years to collect enough data to prove the Outer Banks are indeed a white shark mating ground.

The team intends to go as far as 30 miles off shore, but he says white sharks are tough to catch.

“Even if we catch just one, the expedition will be a success,” he says.

One development that may aid the team is new: A dead North Atlantic right whale is floating past the Carolinas and attracting hungry sharks. If it’s still in the region March 12, the team will head straight to it, he said.

“Everything is pointing to mating being the reason they come here. But I don’t want people to think it (the expedition) is a make or break thing,” he said. “That’s not the case. We’ll learn what they’re doing there regardless of what it is.”

This story was originally published March 9, 2021 at 1:35 PM with the headline "Are Outer Banks shark gatherings part of brutal mating ritual? Expedition seeks proof."