A large hammerhead shark prepares to dine on a tarpon off Anna Maria Island in June 1998. (Photo by Mike Lang/Sarasota Herald-Tribune)

Researchers push to learn more about sharks

 

WILMINGTON -- By the late 1980s, shark populations around the globe were in decline. George Burgess, director of the Florida Program for Shark Research, said as the scientific community scrambled for ways to conserve the creatures, it became clear that sharks were over-fished and woefully under-researched.

George Burgess
"Scientists asked, 'What can we do to turn this around?' And lo and behold, we didn’t have a lot of information about these species," he said. "Scientists, we're aghast if we can't use facts in our decision-making. ... For the first 20 years of fishery regulation in sharks, we were all pulling our hair out."

Burgess said up until that point, research money usually went toward species of fish with more economic or recreational value.

"Sharks were always on the rear side of the line, so we actually knew pretty little about them when all of a sudden it hit the fan," he said.

Two decades later, Burgess said conservation efforts are helping sharks rebound. But for many of the roughly 400 species on Earth, questions about basic facts like lifespan, diet and reproductive capacity remain unanswered. As the animals are again scrutinized after a series of shark attacks in Southeastern North Carolina and the Outer Banks, scientists say learning more about how sharks live may help the public overcome fears about them.

More research needed

Much like the deep waters in which they live, sharks can fill us with a fear of the unknown.

We know what species there are -- 26 types of sharks frequent North Carolina waters, according to researchers. We know that it's rare for them to bite humans -- the International Shark Attack File recorded 72 unprovoked attacks worldwide in 2014.

Beyond that, Peggy Sloan, director of the N.C. Aquarium at Fort Fisher, said a lot more research is needed. She said many U.S. aquariums are focused on research to grow shark populations; at Fort Fisher, scientists are studying the genetics of the bonnethead shark to learn more about its breeding habits.

"We think, 'These are animals that live right off our coast and we should know everything about them.' However, we don’t," she said. "In the wild, it's all pretty difficult because they're invisible and they move."

At OCEARCH, a Utah-based shark research nonprofit, the focus is on tracking the animals, especially great white sharks. OCEARCH's website allows people to follow the movements of more than 100 sharks, tagged with GPS devices that ping when the animal's dorsal fin breaks the ocean surface.

Recently, Katherine, an OCEARCH-tagged, 14-foot great white shark, pinged far south of Morehead City outside Onslow Bay. She had been tagged near Cape Cod, Massachusetts, in 2013. Miss Michalove, an 11-foot tiger shark, pinged in late June near Hilton Head Island in South Carolina -- not far from where she was tagged in Port Royal Sound in May 2014.

OCEARCH's efforts give researches a window into the migratory habits of sharks, animals that Burgess said tend to move widely throughout their lives. While gathering data on a smaller fish species might be as simple as a scientist catching a specimen in the water near his lab, shark research often calls for complex and costly measures: OCEARCH uses a custom-built hydraulic platform to lift one- and two-ton sharks out of the water, giving scientists a 15-minute window for tagging and sampling.

Burgess said a priority for researchers is learning more about sharks' reproductive cycles, which are highly variable between species. He said sharks generally reach sexual maturity between eight and 12 years of age and the gestation period for many species is as long as 18 months. Some shark mothers birth eight to 10 pups at a time, he said, while others have just one pup and some have a litter of dozens.

Fear factor

Fred Scharf of the University of North Carolina Wilmington's biology and marine biology department said what we know least about sharks is what drives their behavior, even during certain attacks.

Fred Scharf
"We have some good rules of thumb," he said, noting that it's common knowledge to stay out of the water if you're bleeding and avoid murky water where fish are feeding. "Those are all things that can minimize your probability of being attacked inadvertently. But you know, it doesn’t take it down to zero. ... When you see lots of attacks occur in a short period of time, or in a very well-defined area, oftentimes we struggle with trying to explain why those attacks may have occurred. And I think that promotes, probably, fear in folks."

Sloan said sharks are some of the most popular animals for visitors to the Fort Fisher aquarium. She said a priority for the aquarium is teaching people the value of the animals in marine ecosystems.

"Sharks play an important role in our oceans: They are the top of the food chain, they are apex predators and they keep a balance," she said. "I’m hoping that people will continue to care about sharks and learn more about them, and that they aren’t vilified because of the bites this summer."

— Cammie Bellamy, Wilmington StarNews