Captain Brett McBride climbs into the shark lift with Mary Lee.
Captain Brett McBride climbs into the shark lift with Mary Lee.

Tracking the Great Whites: What We Can Learn From Genie and Mary Lee

South Carolina surfers and other Lowcountry residents can't stop talking about two white sharks that have been spotted just off the East Coast. But these 16-foot giants may have been swimming in our waters all along.

Captain Brett McBride climbs into the shark lift with Mary Lee.

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For the last couple of months, Charleston, South Carolina’s Post and Courier newspaper has made Lowcountry residents—particularly the divers and surfers—acutely aware that a 16-foot long, 3,465-pound great white shark has been cruising local waters. The shark, nicknamed Mary Lee, was captured and tagged last summer as part of a Cape Cod expedition led by the OCEARCH research team. Since early November, Mary Lee’s GPS tracker has pinged with almost daily frequency as she has cruised and hunted nearshore waters from Jacksonville to Charleston to the beaches of Wilmington, North Carolina. On December 9, Genie, another OCEARCH shark, pinged just off the coast of Savannah, Georgia, proving that Mary Lee’s flukes were no fluke.

Shark tagging. Shark tagging.
This tracking map shows Mary Lee's movements around South Carolina. This tracking map shows Mary Lee’s movements around South Carolina.

Southerners are no strangers to big sharks. In 1964, the world record Tiger shark, a 1,780-pounder, was caught at Cherry Grove, South Carolina’s fishing pier. More recently, the viral video of an assault by a big bull shark on a Myrtle Beach red drum made tidal creekgoers from Capes Hatteras to Canaveral just a little nervous. Still, we southerners are not at all used to great white sharks, and Mary Lee has become a source of regular conversation in the surf lineups from Tybee to Masonboro Island—particularly because surf forecasting and Google mapping are pushing more and more of us to explore remote shoals and outer sandbars along our coastlines.

To satiate a little morbid curiousity, I had a chat with Arnold Postell, senior biologist at the South Carolina aquarium in Charleston. Postell then put me in touch with a colleague—Dr. Salvadore Jorgenson, a research scientist with the Monterey Bay Aquarium. Jorgenson then suggested I finish the conversation with Dr. Greg Skomal, a biologist with the Massachusetts Division of Marine Fisheries who helped tag Genie last summer off Cape Cod.

What follows are excepts from those conversations.

Arnold Postell, senior biologist at The South Carolina Aquarium

There’s a good bit of chatter on the surfing and fishing bulletin boards and in the lineups about Mary Lee and Genie. We don’t usually associate nearshore southeastern waters with great whites.
Not a lot known is known about great whites on the East Coast. The focus has traditionally been on California, Australia, South Africa. But I think that the tagging research that’s been going on may point out another geographic area to study them. It’s been known that they were around here—fishermen would confirm sightings, and we had one that turned up dead off Morris Island a few years ago (2008). So every year, every other year, we might get a sighting. But now that they’re actually being tracked—no one had been seeing these animals—I think what we’re realizing is that offshore in the southeast, our local waters, not even out to the Gulf Stream, might be a wintering spot for great whites. That’s kind of an unknown that we’re figuring out right now.

It’s amazing to see the video footage of the guys standing alongside the sharks on the Ocearch boats, and to realize we share water with a predator of that size.
One take home I’ve had from this is that it’s probably been going on as long as we can think of; we’re just now getting real data about it. So I wouldn’t say it’s a new phenomenon—the phenomenon is that we’re learning about it in real-time while it’s happening. I mean, how many great white attacks have there been in Charleston ever? It’s important to keep that in perpsective. I saw the ping off Kiawah, and Mary Lee is definitely close in, but I think that’s probably been going on all along. I grew up surfing out here too.

With this real-time data out there now, I can’t wait to see where they go and come back. The next few months will be quite telling. Really, this opens up a whole new window of opportunity for researchers to study great whites in the southeast.

They’re known as a more cold-water species. Is it a surprise they’re down here now?
Well, temperature is the big quirk. My first response is no because of the nearshore water temperature (around 55 degrees). It’s pretty cold here now, but in August, you have 80, 85-degree water. So they go back to the northeast. In California, the water’s cold year-round. It’s interesting, if you look at their tracks, they’re not really going out to the Gulf Stream; they’re riding out that cold water channel right on the inside, close to shore. Because 40 miles out at the Gulf Stream, the water’s still 75 degrees.

There’s a good zone of food between the Gulf Stream and shore.
Definitely. I’ve been diving in December—we go out to Charleston 60, a real close-in wreck. One of the best dives I ever had out there, we found hundreds of amberjacks, and 50-plus big bull red drum just in a feeding frenzy over baitfish. Now that folks have GoPros, they’re dropping them to the bottom where they’re fishing. I was watching someone’s footage yesterday—hundreds of black sea bass and sheepshead. So we have plenty of food for a big predator.

Southern North Carolina, South Carolina, Georgia is a region called the South Atlantic Bight. It’s one of the least well-known and most diverse fisheries because it gets a great blend between the warm water southern animals and the cold water northern ones. The waters are also very well managed, and that’s not only a benefit for fishermen, but also for sharks.

So we’re obviously not so high on the food list.
They do a lot of research on feeding behavior of great whites—things like using artificial seals for lures. I don’t think great whites go around just biting everything. Some sharks, like bull sharks, people always laugh at the stuff they find in their stomachs. I don’t think great whites fall into that category.

Given the track of Mary Lee, would you think twice about any of the outer shoals and bars as a surfer?
In the summertime, not at all. In the wintertime, I always lean back on—and I don’t want to brush over the fact that we have a 16-foot great white in our waters, but I go back to the fact that they’ve been here all along and we haven’t had those interactions. Now there is one offshore shoal you and I know of in particular—you’re out in the ocean and the water’s a lot clearer. Would I go surfing out there right now? Well, that probably depends on where the last ping was.

Dr. Salvadore Jorgenson, a research scientist with the Monterey Bay Aquarium

Can you give sort of a general idea of the known and unknowns of great white migratary behavior along the East Coast versus California?
We’ve been studying white sharks a lot longer on the West Coast than the East Coast—we’ve tracked over 100 out here, so the insights we’ve gained might have some relevance on the East Coast, where they’re much less studied. One thing we’ve learned is that the more you look, the more you see them. They move around and are closer to populated areas than we probably expect. The more we tag them and look for them, the more we realize that they’re around. A good example: We’ve known for a long time that white sharks are here around San Francisco, but recently, we’ve been tracking them entering the San Francisco Bay. Well, there are a lot of people who swim out to Alcatraz—open water swimmers—and the Alcatraz swim is fairly popular. So the talk, when people are pulling their bathing caps on is, “Oh yeah, the sharks are probably here,” but it was sort of legend until we started to get some data back that, yes indeed, the sharks do come under the bridge and they do swim around Alcatraz. So the take home from that is: I think the last time there was even a shark that bit someone in the area was back in the 1950s at Baker Beach near the Golden Gate, so we’re over 50 years without an attck. But when we put on the tags, we realize that the sharks are swimming around that area—and under the bridge—all the time.

My friends and I have been amazed at how close Mary Lee in particular comes to the beaches here—we even had a 13-foot juvenile die after it beached on Morris Island a few years ago—right by one of our favorite sandbar breaks. That was the first time most anyone here had even heard of great whites in our waters.
I’m a surfer too—I surf out here in California—and when we realize that they’re there, and they’ve been there the whole time we’ve been surfing, you sort of go, Well, okay. On the East Coast, it’s sort of a new finding because they haven’t tagged too many sharks. But the same point I wanted to make is that, from what we’ve learned from sharks on the West Coast but also around New Zealand, part of the year they move into warmer waters. So it’s not really surprising that in the fall they were out off Montauk and then moving south after the winter’s coming on. That’s what they do out there. And those same sharks will probably end up going back up north the following year.

The waters along the shoreline of the East Coast tend to be murkier and shallower than the West Coast. Maybe our hope is that the shallowness of the water or the murkiness will somehow make it less likely that we’ll have a direct encounter.
Well, really, I think they run the whole range. We have sharks in San Francisco Bay where it can be shallow and murky. The Farallon Islands, the waters are much clearer and right along the edge of the Continental Shelf. So I don’t think they display much of a preference either way. Greg Skomal in Massachusetts can talk more about this, but the fact that they’re seeing more sharks on the East Coast seems to be tied to the fact that more seals have been hauling out in the northeast. Of course, here in Central and Northern California, where they haul out, we have a lot of sharks too.

Really as a surfer, I consider it more dangerous to actually drive to the beach than actually being in the water. But there’s this morbid fascination—the idea that you’re not in control. That there’s this larger, wild animal that could get you. You don’t feel that way driving a car, but it’s many, many times more dangerous to drive than to paddle out.

Dr. Greg Skomal, a biologist with the Massachusetts Division of Marine Fisheries

Dr. Jorgenson pointed out that we know far less about the movements and habits of white sharks on the East Coast than most other so-called hot spots around the world.
It’s true. The bottom line is that we don’t know a lot about this particular species in the Atlantic. Up here on the northeast coast, we’ve known that in the summer months you can find lots of blue sharks. More recently we’re finding the same is true of white sharks. There’s a changing dynamic up here, and in the last few years we’ve had unprecedented access to these animals, and that’s let us put tags on them.

Because of the increase in seal populations?
Like many other parts of the world, we’ve had a restoration of the seal population up here—a high seal abundance and thus a high predator abundance. They’re being drawn in close to Cape Cod. We’ve tagged 34 sharks in the last four years, but the ones that get the most attention are the ones that are tagged by OCEARCH because you can track them in real-time.

It’s nothing really new that they do occur off the southeastern coast in the winter, but what’s bringing it home to people is the fact that it’s now being brought to them live so to speak. They’ve been there, but they’re just not a conspicuous species. Not a lot are caught. They keep to themselves and don’t spend a lot of time very close to shore—they tend to stay a few miles out. You don’t have seals piled up on the beaches like we do up here, which draws them up on the shoreline. Off the southeast, they’re shifting gears, to feed on porpoises, dolphins, and big drum and amberjack. And they love to scavenge dead right whales.

I guess it’s as much an issue of being comfortable in your ignorance than when you can see them right there on the screen—right offshore.
Folks up here have said, “Jeez, I felt a lot more comfortable when I didn’t know these things were around.” Some don’t like to surf up here in the summer because it’s a psychological issue. We haven’t had an attack on a surfer ever, but last year we did have an attack on a swimmer. Up here, because the seals are drawn right up on the beach, those fears may be a little more founded than yours.

The other tags you’ve put on sharks have been done without actually capturing them. But you helped tag Genie, the shark that pinged off Savannah, by getting her aboard the OCEARCH platform. The video of that capture was remarkable.
That was my first time tagging a shark that way. It was amazing. It’s probably the same feeling you would have looking at really big waves. It has to do with how insignificant it makes you feel. We put big, black towels over their eyes to keep them calm. Then, to see an animal in excess of 2,000, 3,000 pounds before your eyes, just laying there, docile like a big old St. Bernard, and being able to tag it, take tissue samples, test for parasites. It’s just remarkable.

How long is it safe to keep them on the platform?
Nobody wants to push it. OCEARCH is conservative. They say no more than 15 minutes. You could probably push it to half an hour, 45 minutes and the shark would be fine, but nobody wants to do that.

Are these eastern sharks as battle scarred as the ones you see out west?
We’re just finishing up some research that indicates that this species may live 70 to even 100 years. So these are big, old animals. You think of any big, old animal that’s dealt with the elements and survival—even though they’re the top dogs in the ocean, there are other top dogs, too. And every time a shark goes after prey it’s taking a risk. So they’re going to be scarred up. I’ve been down in a cage with them and it’s like looking at an old Navy veteran—like Quint in Jaws—where you look at them and sort of ask, Wow, where did you get that scar?

Any surprises to you in the movements of these Eeastern sharks?
Well, almost all the information is new, and that’s the beauty of it. One of the things we found out from early tagging in 2009 and 2010—we knew that white sharks spend winters off the coast, anywhere from southern North Carolina down as far as Cape Canaveral. The classic thinking was that they move off the northeast and then to North Carolina, South Carolina, Georgia, and then Florida, but in fact, the movement is not linear at all. Mary Lee—she moves from Georgia to South Carolina in a few days and just goes back and forth. It’s almost a random movement, and we’re just learning about all of it as we go along.

Chris Dixon is author of Ghost Wave: The Discovery of Cortes Bank and the Biggest Wave on Earth. He is more afraid of big sharks than big waves, but just barely.

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