Sharks make headlines, but we don’t actually know a whole lot about them—including how many there are out there. Counting the number of sharks in the ocean presents a logistical nightmare for us air-breathing humans. More than 500 species of sharks roam the globe with no set address. Given this, organizing a global census of every shark is quite the challenge.

But that’s exactly what co-founder of Microsoft and philanthropist, Paul G. Allen, asked shark researcher Demian Chapman of Florida International University to take on. Concerned by the continual decline of shark populations due to human development and shark overfishing, Allen wished to create a massive shark and ray counting initiative. His previous project counting African elephants via airplane surveys led to a massive database that not only pinpointed elephant populations but also showed where their numbers were increasing, decreasing or stable. If scientists could determine elephant populations via standardized airplane surveys, why couldn’t a similar concept be applied to sharks?

Enter Global FinPrint. The project is a three-year research initiative that began in 2015 led by Chapman and a group of renowned shark biologists. It aims to document the number and species of sharks and rays that live in reefs around the world. But surveying sharks is a bit trickier than surveying elephants. Most sharks live too deep to be detected via an aerial survey, so instead of aiming to count every single shark and ray, the project is looking to find the last major refuges where the animals thrive. If scientists can better understand where sharks like to congregate, perhaps they can use the information to guide effective conservation efforts. 

“The loss of sharks is a global environmental problem but it’s one that we don’t necessarily have the science and conservation experience to know how to reverse,” said Chapman.

Unable to rely on planes, the FinPrint team turned to baited remote underwater videos (affectionately nicknamed BRUVs) as a way to attract and document the sharks. A BRUV has a steel tripod base with a GoPro attached on top that is focused on a baited cage. Smelly fish scraps, like tuna or mackerel, attract local sharks to the BRUVs, which then capture the hungry visitors on video. The BRUVs are left underwater for 60 to 90 minutes and then retrieved so the video can be analyzed and the number and types of sharks at that location recorded.

Chapman used BRUVs in previous small-scale studies in the Bahamas. But he quickly realized that using BRUVs for a one-time research project at a specific location is already a challenge. The tripods are clunky, and it’s most efficient to make them on site near the reefs where they will be placed. Scaling up to use them globally meant the team needed to make several tweaks to the design. An impromptu brainstorming session between Chapman and a friend resulted in an expandable, foldout design similar to an umbrella. The new BRUVs could now accompany scientists in duffel bags as they traveled to remote field sites across the globe.

So far the cameras have caught some pretty amazing videos that have left even the shark and ray specialists in awe. Roughly 216 reefs have been surveyed and the goal is to complete 400 by the end of the project in 2018.

In the Bahamas, a Caribbean Reef shark was taped casually making its way to a BRUV and then suddenly it skirts away. Out from behind a great hammerhead appeared—even sharks are scared of sharks! In other videos, massive rays like the blotched fantail ray of the Great Barrier Reef suddenly blanket the camera’s field of view. Credit: Global FinPrint

In an upcoming trip this fall, Steve Canty of the Smithsonian Marine Conservation Program will join Chapman at a particularly interesting site off the coast of Honduras. In 2011 President Porfirio Lobo Sosa declared the entire coastline of Honduras, nearly 240,000 square kilometers (92,660 square miles), a shark sanctuary where both fishing and trading sharks is illegal. Canty will set up nearly 300 BRUVs at six separate reefs near a string of three islands—Roatan, Guanaja and Utila. He hopes to see the great hammerhead, an endangered shark once common in the area. “The fishers used to say that you couldn’t put your toes in the water when you were a kid in case they got nibbled by the (hammerhead) sharks, and now you barely ever see one,” said Canty.

But prohibiting shark fishing altogether isn’t always possible. Often, local communities rely on either sharks, or the fishing gear that entangles them, to make a living. The strength of FinPrint lies in its ability to tease out what works in shark conservation. In some areas, it may be that prohibiting shark fishing is the only option, perhaps because the local reef doesn’t have the food supply to sustain a healthy community of sharks.

“I’m very interested to see Honduras, because Honduras is a relatively recent shark sanctuary, but I know they still allow the types of gear that sharks get caught in. Even though it’s illegal to catch sharks there’s still accidental catch of sharks, so it very well may be undermining that rule,” said Chapman.

Other countries rely on different strategies. Just up the coast, Belize manages several no-take marine protected areas that also ban harmful fishing strategies like long lines and gillnets. Instead of banning shark fishing all together they’ve designated several pockets where sharks can seek refuge. And the Bahamas are a standout in the Caribbean—since 1990 the government has banned both shark fishing and the use of gillnets. BRUVs set in the Bahamas always seem to capture the most sharks.

The most exciting revelation of FinPrint is the discovery of “brightspots.” These are areas that are neither remote nor protected, and yet shark and ray populations are relatively healthy. “They’re the ones where we go ‘huh, we wouldn’t have expected that to be such a good place.’ Once we identify a place like that we can drill down and figure out why—why is that place doing so well?” said Chapman.

One such brightspot already identified is in Trinidad and Tobago. Off the coast of Tobago local fisherman use handlines—think your standard fishing pole—instead of the more harmful longlines and gillnets. The shark populations in the region seem to be thriving—a study is currently underway to pinpoint what makes this fishing system work so well.

At a time when shark conservation is often a tale of doom and gloom, it’s heartening to see that in some places around the world sharks and humans can coexist. Sometimes what seems like an impossible task can lead to a hopeful future.