In the turquoise waters off Florida’s East coast, Captain Douglas Covin cuts his boat engine and waits. Within minutes, they arrive – six 300-pound bull sharks circling expectantly. 

The moment a sailfish takes his line and before he can even begin to reel it in, the sharks strike, leaving him with only half a fish on his hook.  

This scene has become common in what fishermen and researchers are now calling a serious case of “shark depredation,” when sharks snatch or partially eat hooked fish before anglers can reel them in. 

“Sailfish go to eat the bait and before they even eat the bait, sharks are there pouncing and eating the sailfish,” Covin said. “They’re eating everything.”

At Florida Atlantic University’s Elasmo Lab, or “Shark Lab,” researchers are diving deep into this issue. According to a Biological Sciences professor and FAU’s “Shark Guy,” Stephen Kajiura, many anglers argue that there are too many sharks. They offer a different perspective: shark populations are stable and not as abundant as they once were. 

“Shark populations are coming back up, and it’s because of effective management and fisheries regulations over the past several decades,” Kajiura said, noting that the bigger shark populations in the 80s and 90s were fished down. “People weren’t alive 100 years ago. They didn’t see what the shark populations were like. They’re not even up to their historic levels yet.” 

This view is supported by global data showing that 71% of oceanic shark and ray populations have been depleted in the last half-century, and one-third of all 1,199 known shark and ray species are now threatened with extinction, primarily due to overfishing, according to a 2021 study from the International Union for Conservation of Nature. 

Florida has several different mandates to curb the number of sharks being fished, including limiting the shark harvesting to two per vessel and listing 25 shark species as “prohibited from all harvest, possession, landing, purchase, sale or exchange.”

For the state’s vibrant fishing industry, which generates about $9.2 billion in recreational revenue according to the Florida Fish and Wildlife Conservation Commission, these preservation efforts deeply affect fishermen. 

Covin, who runs a sport fishing charter in Jupiter and fishes about 200 days per year, says the evidence is clear in what he doesn’t bring back to the dock. 

Seven years ago, Covin and three other local captains combined counted 100 sailfish eaten by sharks in the span of six months. Now, 50 sailfish are being eaten per weekend on his boat alone.

His frustrations led him to manage a Facebook group called “Sportsmen Fighting for Marine Balance,” which has swelled to over 7,000 members who share similar stories. 

“It used to be that recreational and commercial fishermen were always at odds, and this was the first time we’ve seen that commercial fishermen and recreational fishermen have really come together on the subject and work together, as we realize how bad it is,” Covin said. 

FAU researchers have begun quantifying how widespread this issue is. Michael McCallister is one of them. He is a doctoral student and research coordinator at FAU Harbor Branch, who conducted a large-scale survey of Florida anglers. 

“At least 43% of people experienced depredation at some point when they’re fishing,” he said. Among those who encountered depredation, sharks consumed an average of 40% of their catch. 

But the toll extends beyond lost fish. 

“It could be frustrating emotionally but also for economic reasons. You’ve got to replace that gear,” said Matthew Ajemian, who has been studying sharks at FAU’s Harbor Branch campus since 2016. 

For charter captains, repeated shark interactions can lead to disappointed clients. 

“The charter boats have kids come, and it’s pretty sad when you have some 10-year-old kid, and his father spends thousands of dollars to go on a charter, and he comes up, and he reels [the fish] in, and as it’s coming up — the sharks eat it,” Covin said. 

Both McCallister and Ajemian have witnessed the depredation issue firsthand, not only from a researcher’s standpoint but also from a recreational standpoint. In their February study this year, they have already identified bull and sandbar sharks as the primary culprits by swabbing depredated fish carcasses to look for DNA evidence.

“As far as the sharks being overly abundant, I don’t think anybody can really say that without knowing what it was like in previous times,” Ajemian said. “There’s still rebuilding that needs to be done.”

The debate around shark populations often comes down to perspective. Ajemian explains this as “baseline syndrome.”

“For us, it may seem like there’s a lot of sharks because I was born 40 years ago, and back then, there weren’t as many sharks as there are now. If there’s somebody who’s twice my age, say, 80 years old, they may have a very different opinion of that, because they’ve been around longer and probably have seen more changes in the population,” Ajemian said. 

McCallister, pursuing his doctorate part-time while working as Ajemian’s research coordinator, believes the issue is here to stay. 

“I don’t think it’s a problem that’s going to go away. We’re not just going to have sharks disappear from the oceans, and human populations are increasing in recreational fishing, particularly in Florida,” he said.

For FAU’s shark researchers, solutions might lie in technology. Kajiura mentioned his lab is developing ways to reduce shark depredation in commercial fisheries. 

“We’re developing technology that will keep the sharks off the hooks, but still allow the fishermen to catch what they want,” said Kajiura. “It’s much more profitable for the fishermen, better for the sharks. They don’t get caught, everybody wins.”

One shark-repellent approach leverages sharks’ ability to detect electric fields, something other fish can’t do. 

“If you create an electric field that’s basically too strong,” Kaijiura suggests, it could deter sharks without affecting the fish anglers are trying to catch. He said fishermen can already find these magnet-based shark repellents that attach to fishing hooks on the market, but FAU is currently working on a better version. However, the details on how it will be improved are still top secret. 

For recreational fishermen, solutions might be simpler but require adaptation. McCallister proposes techniques like reducing tension on fishing lines, “so the fish can outswim the sharks if there are any.”

“I think we need to realize that those sharks are not going away,” said Ajemian. “And we just need to deal with it.”

Some anglers advocate for policy changes, including reconsidering the 2020 shark fin ban in Florida, which prohibits the sale and trade of shark fin despite high demand in Asian markets. 

“Congress put through a shark fin ban, so we cannot export any fins. So even though we’re catching sharks, they have to take the fins and throw them in the garbage, even though there is a demand for it in Asia,” Covin said. The result, according to Covin, is that “there is no commercial shark fishing left,” despite it technically being legal. 

Covin says that even though commercial shark fishing is legal in the state, because of the fin ban, there’s no incentive to go out and catch sharks. 

“What we would like to do is repeal the shark fin ban and then have a sustainable balance of sharks being caught here,” he continued. “In no means do we think we need to wipe out all the sharks…but there needs to be a balanced ecosystem.”

Covin and many anglers blame shark feeding, which is legal in federal waters beyond Florida’s three-mile cut-off. 

“They train the sharks to listen to the sound of an engine, and they relate the sound of the engine to getting fed,” Covin said. “Sharks need 100% protection in certain parts of the world. Here? No.”

Kajiura offered a different explanation.

“There’s a lot of sharks that come down here in the wintertime and they spend the winter here, and then as the water warms up, they migrate back up north again,” he said. “They’re like snowbirds.”

Part of what fuels this debate, according to Covin, is a cultural divide in how sharks are perceived compared to other marine life. 

“Most people, in general, love sharks, because we’re brought up as kids with shark cartoons and stuffed sharks,” Covin said. “The kids don’t have stuffed tuna or snapper or grouper. They’re not taught to love them, they’re taught to love sharks.”

This shark favoritism, Covin argues, misses the bigger picture. 

“Without sharks, are we afraid there will be too many snapper and grouper and tuna?” said Covin. “If there are too many snappers out there, we’ll be able to feed the world.”

He pointed out that 80% of all fish they catch on his charter boat are released back into the ocean.

“Some people don’t understand that fishermen are conservationists,” Covin said. “Who’s going to want to save the ducks more than duck hunters? We’re not going to be able to fish if there’s no fish around.”

For fishermen like Covin, the future is concerning. 

“My nephew loves to fish, and I don’t know if he’ll be able to fish at all, eventually if it continues like this,” he said. “We’re out there all the time and can see what’s going on. I want the next generations to be able to fish.”

This story is in the UP’s latest print issue, Vol. 32, “Earth Day: Exploring Environmental Research and Wildlife at FAU, which can be found in the distribution boxes around the Boca Raton campus or in the Student Union Room 214.