Here’s what it’s like to dive through French Polynesia’s shark alley

“Are you ready to see some sharks?” asks my dive guide, Thibault Gachon. His question is rhetorical.

We are preparing to dive off the atoll of Fakarava in French Polynesia’s Tuamotu Archipelago, part of a UNESCO biosphere reserve, where some of the most reliably shark-filled waters in the world await.

Gachon, who runs dive outfitter O2 Fakarava, smiles and slips on his regulator. We giant-stride off the back of the boat, dropping straight into one of the ocean’s most exhilarating–and accessible–underwater views.

We are in the middle of a narrow pass, Tumakohua, at the atoll’s southern end. It’s one of only two tidal channels that flow into the Tuamotus’ second largest lagoon–which covers an area more than six times the size of Washington, D.C.

At this lagoon entrance, sleek gray reef sharks assemble like puzzle pieces coming together, each animal roughly five feet long. They turn the ocean’s middle distance a slate color with their sheer abundance.

Gachon and I descend to about 80 feet and hold onto rocky bits of the reef in the current to take in the view. The stiller we stay, the closer the sharks appear to come. It’s like the ocean itself is exhaling them our way.

A shark spectacle like no other 

In fact, the particular behavior of the gray reef sharks here can be better likened to an energy-saving conveyor belt, says Florida International University marine scientist Yannis Papastamatiou, who studies the physiological and behavioral ecology of marine predators and has spent hundreds of hours diving in Fakarava’s south pass.

“During the day, they are not hunting here,” he says about the gray reef sharks, which are negatively buoyant and will sink if they stop swimming.

(This chart explains how quickly sharks are dying out worldwide.)

The sharks use current updrafts in much the same way soaring birds take advantage of updrafts coming off a mountain to stay aloft, Papastamatiou says. “The upward current counteracts the negative effects of gravity on the sharks,” he says.

While the sharks may appear almost motionless in the water, they are in fact sinking very slowly. They use the updraft to drift forward through the water and then let the current return them to the place where they first entered to do it all over again. The result looks like a never-ending conveyor belt of sharks, which can number in the hundreds on any given day.

“This behavior basically reduces how much energy the sharks have to expend,” Papastamatiou says, explaining that the current forces water over their gills and reduces the animals’ energy expenditures by an estimated 20 percent or more.

Gray reef sharks hunt during the night. The abundance of fish in the atoll’s lagoon, boosted by regular spawning aggregations, are thought to be one of the reasons for the unusually large presence of gray reef sharks here.

Sharky isles 

Sharks have been protected in French Polynesia since 2006. Fakarava is hardly the only place in the Tuamotus where gray reef sharks abound–among many other species, including white tips, black tips, tiger sharks, great hammerheads, and lemon sharks.

At the Mokarran Protection Society on Rangiroa—also in the Tuamotus and the second largest atoll in the world—scientists study endangered great hammerhead sharks. They can often be seen by scuba divers during recreational dives here and elsewhere in the archipelago.

And on the atoll of Tikehau, professional freediver Denis Grosmaire of Tikehau Ocean Tour, who has been diving with the lagoon’s tiger sharks for many years, is embarking on a project with the Center for Insular Research and Observatory of the Environment on Moorea through the end of 2022 to collect skin samples from the animals for genetic testing.

“Now that I know these sharks very well, I see them growing, I see them pregnant and not pregnant anymore,” says Grosmaire. His work will help determine relationships between the sharks that appear to be residents on Tikehau and those from surrounding islands, enabling scientists to learn how transient the species is.

Cultural reverence and respect

 To the people of French Polynesia, sharks are tāura—totem animals and guardians—both for family groups as well as whole island groups, says Matahi Tutavae, a Tahitian filmmaker and storyteller and the founder of Faafaite-Tahiti Voyaging Society.

“They are navigators but also guardians of places,” he says. 

(Find out why sharks form years’ long “friendships” with each other.)  

Tutavae recalls being on a sailing trip, among a fleet of traditional Polynesian canoes on approach to Fakarava from Tahiti. The group came to a full stop after three days of sailing to perform a ritual that a local woman from Fakarava had advised them to carry out between the two islands.

“When you go somewhere in Oceania, it’s always about asking permission and making your intentions clear—both to the people who live there but also the ancestors,” Tutavae says. “She taught us a prayer, like a key to open a door.”

He said his group began a ceremony in the middle of the ocean to ask permission to approach Fakarava’s lagoon. Half an hour later, he said, a juvenile oceanic white tip shark, the totem animal of Fakarava, came and touched the hull of the canoe.

“To us it was a good sign,” Tutavae says. “Sharks were never a threat to us, until pretty recently when people started feeding them and changing their habits.”

Travelers who visit this remote corner of the world should approach sharks with reverence and respect, he says. Avoid tour operators that feed the sharks, educate yourself about the animals, and enter the ocean with an open mind.

“It’s hard to respect something you don’t know or understand,” Tutavae says. “We are so lucky to be able to go in the water and see all these animals, sharks and whales, here.”

(Here’s what kids can learn from sharks.)

“We are in the middle of the Pacific Ocean on some reef islands that are very, very rich,” says Grosmaire. “When there are a lot of sharks, there are a lot of fish. And when there are a lot of fish, there are a lot of sharks.”

For his part, he says, he enters the water always with a message of love, respect, humility, and gratitude for the sharks.

“They decide to show, they decide to come,” he says. “Me, I am just here waiting.