Fishermen targeting sharks in the 1970s led to decline

Shark fins could become a more common sight in the Atlantic Ocean, according to a new study.

In the early 1990s, shark populations had declined to dangerously low levels due to overfishing and lack of a management plan. To respond, the National Oceanic and Atmospheric Administration implemented a fishery management plan for sharks and started monitoring them.

The results of those efforts are not quickly evident because sharks – particularly large ones – are slower to mature and reproduce at lower rates than many other fish. But a team of researchers led by a graduate student at William & Mary’s Virginia Institute of Marine Sciences combined data from six shark surveys and created a model that indicated the management efforts have been effective.

“The context of shark population status over the past few decades has been pretty doom and gloom,” said Cassidy Peterson, the graduate student who headed the project. “It’s been a story of all of these big shark declines in abundance into the 1990s and because they’re so slow-growing and slow-reproducing, the story sort of was that they weren’t going to increase in abundance anytime soon.”

Chuck Bangley, a postdoctoral researcher at the Smithsonian Environmental Research Center, said the study backs what researchers have seen in recent years and is an indicator that NOAA’s management plan was a net positive.

“It’s a sign that what we’re doing as far as shark fishery management seems to be working,” said Bangley, a shark expert who studied at East Carolina University in Greenville.

To evaluate the comeback, the team estimated trends for larger species such as blacktip, sandbar, spinner and tiger sharks, as well as smaller ones such as the Atlantic sharpnose, blacknose and bonnethead sharks. Since the management plans were enacted, according to the researchers, every species but blacknose sharks have seen population increases.

Increased competition

Part of the initial decline was fishermen targeting sharks in the 1970s after the predators attacked their nets. Wesley Potter, a N.C. Fisheries Association board member who lives just outside New Bern, said shrimpers off the North Carolina coast are beginning to again see sharks’ impact.

“They’ve really made a strong comeback,” he said. “I know a lot of shrimpers have trouble with them biting up the tailbags with them out in the ocean when they’re shrimping and eating up the gill nets, that kind of thing.”

Glenn Skinner, another member of the fisheries association board, stopped fishing in the Atlantic three years ago because sharks were destroying his gear too quickly.

“You can hardly work because there’s so much damaged gear,” he said. “You take the gill nets for a small fish: They’ll try to take the fish out of it, they’ll just destroy the net.”

Skinner also questioned whether fish management practices should focus on sharks at the top of the food chain. Instead, he said, they should focus on stressed fisheries such as spot or depleted ones such as weakfish.

A positive sign

But more sharks in the ocean is likely a positive sign for biodiversity, said Bangley – a point echoed by Rob Latour, a William & Mary Virginia Institute of Marine Sciences professor who worked on the study.

While sharks have struggled, species they hunt such as rays and skates have boomed. Now, with the predators returning, there is a chance for the ecosystem to return to its former state.

“Sharks are viewed as being the apex predators of the food web,” Latour said, “and as such they have the ability to regulate food web dynamics in a top-down manner, if you will, so their re-emergence could be viewed as positive.”

Vacationers taking a dip in the Atlantic are more likely to have an encounter with sharks, Latour added, but the possible comeback isn’t a sign swimmers should be more afraid this summer even after the spate of shark attacks off the N.C. coast in 2015.

“With more sharks there does come an increased probability of encounters,” Latour said, “but in the grand scheme of things, you have a far greater chance of getting in a car accident on your way home from work. ... Just use smart tactics.”