Credit: Florida International University
In the heart of French Polynesia, a narrow channel carves its way through the Fakarava Atoll, connecting a vast lagoon to the open ocean. To the casual eye, it's a beautiful stretch of turquoise water. To a thriving community of grey reef sharks, it's a bustling metropolis, a nursery and a sanctuary all in one. And it might just be the key to solving a perplexing conservation challenge.
Scientists and conservationists have long grappled with how to best protect highly mobile animals, like sharks, that roam across massive areas. The solution, though, might be less about scale and more about super-habitats, according to Yannis Papastamatiou, an FIU associate professor of biological sciences and marine researcher in the Institute of Environment.
A little more than half a mile long, the Fakarava channel supports a large population of approximately 500 grey reef sharks. All the major behaviors of their life can take place in the channel, including mating, having babies and even cleaning, according to new research published in .
"By safeguarding these unique corridors, we could protect a disproportionately large number of sharks and ensure the continuity of their entire life cycle in a relatively small area," Papastamatiou said.
Through a combination of underwater observation and high-tech tracking tags called biologgers, the researchers documented the sharks using the channel for nearly every critical behavior. They were observed foraging for food and resting in tidal currents, things the scientists already knew were common activities in the channel. They also observed females with fresh mating wounds, mating behavior, and very young sharks swimming around.
Credit: Florida International University
The scientists even obtained a rare, short video of a shark giving birth to a pup in the channel. They also observed sharks visiting special "cleaning stations" where smaller fish remove parasites on them. Many of the tagged sharks spent as much as 90% of their time there.
"We don't know how rare these super-habitats are. Fakarava channel may be unique, but I suspect there are others," Papastamatiou said. "Super-habitats are never going to replace the need for large protected areas, but they should definitely be included in conservation planning and efforts."
The Fakarava channel is part of a larger protected area and part of a UNESCO World Heritage Biosphere Reserve. Despite its small size, the high quality of the Fakarava channel is tied to the abundance of prey fish, the tidal currents that bring oxygen-rich water to the sharks, and the areas ideal for rest. The researchers say it would be worthwhile to search for other super-habitats to help safeguard species.
More information: Yannis P. Papastamatiou et al, Marine predator super-habitats: Channels used for foraging, resting, mating, and parturition in sharks, Biological Conservation (2025).
Journal information: Biological Conservation
Provided by Florida International University