New Study Finds That Reef Sharks Are 'Functionally Extinct' & Here's What That Means

The population of some of the ocean's biggest predators looks to be dwindling.

Sharks have been found to be "functionally extinct" in nearly one in five reefs surveyed as part of a new study done by researchers from the conservation organization Global FinPrint. For the study, published in the Nature journal on Wednesday, scientists used remote underwater video systems to survey the marine life living in 371 reefs in 58 nations across the globe. What they found was shocking: Of all the reefs observed, sharks were only detected in 20 percent of them.

No reef sharks were spotted in countries like the Dominican Republic, the French West Indies, Kenya, Vietnam, the Windward Dutch Antilles and Qatar. Meanwhile, reefs in regions near Australia, Bahamas, Federated States of Micronesia, French Polynesia, the Maldives and the United States—where governments, researchers and community members have taken broader steps to protect coral reefs—had significantly higher sightings of sharks.

Although the shark findings were relatively low in various reef ecosystems across the globe, this doesn't necessarily mean reef sharks are gone forever, Dr. Mike Heithaus, Global FinPrint co-lead and Dean of the College of Arts, Sciences & Education at Florida International University, told Newsweek in a phone interview on Thursday.

"This means that shark numbers are so low in certain areas, they're not filling the role in the ecosystem like they should. When you look at most ecosystems, when you lose top predators bad things happen," Heithaus explained. "The good news is that the sharks aren't extinct, it's just that they're largely missing from certain areas."

The paper suggested increasing human population density likely played a role in the changes to reef shark populations, as well as global government failure to address problems like over-fishing. But incorporating laws and practices like banning gillnets and longlines, putting catch limits on shark finishing and having larger closed-off waters could go a long way for rebuilding populations.

New Study Finds Sharks Are 'Functionally Extinct'
Sand Tiger sharks and a barracuda swim in a tank at the Florida Aquarium exposing Floridas natural ecosystem on August 22, 2019, at Apollo Beach, Florida. A new study found no traces of sharks after montioring nearly 400 reefs in 58 countries for hundreds of hours. GIANRIGO MARLETTA/AFP via Getty Image

"The choices we make in terms of the seafood we eat or just how we live our lives and our carbon footprint can make a difference for oceans and for sharks. Also traveling to places to just see the reef sharks that are there—one of the ways that you can help communities thrive economically as they fish less is through ecotourism. Just that kind of support, legislation and policy will help," Heithaus said, adding that better management of coral reefs was just as important. "You can't protect sharks in a vacuum—those reefs also need to be protected. One of the reasons that we started this study and really focused on those coral reefs for sharks is because we didn't know a lot about them. But coral reefs are just so important for people."

Despite the bleak findings, there is one silver lining. The study not only helped researchers become better equipped in pinpointing exactly what efforts each country needs to rebuild shark populations, but it essentially helped them form a greater network of people ranging from scientists to lawmakers and community organizers, who are all aiming to help reef sharks fill their ecological role.

"These reef sharks are in real trouble in a number of places, but are these reservoirs of hope where we still have intact shark populations. If we get the management right, we have places we can rebuild from. That's one positive," Heithaus said. "I think just that working together across all sectors is how we're going to be able to get solutions not just for sharks and coral reefs but for the people that rely on them, too."

Even with efforts focused on rebuilding, it will still take time to see an uptick in the population because of the naturally slow growth and reproduction rates of sharks.

"It will take years to rebuild but it can happen. We've seen examples in different parts of the world of when you do start protecting sharks, their populations do start coming back," Heithus said. "The good news is some of these reef sharks do reproduce a little more species that grow super slowly. If we get started, we can make a difference."