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Tracking Young Great Whites Off the Coast of Long Island

This area of the Atlantic has been known as a nursery for the apex predator for decades, but no one has attempted to study these sharks' movements—until now.
Great white shark.

Great white shark.

"I'm flipping out!" Greg Metzger exclaimed, dancing about the deck of his boat.

As chief field coordinator for the shark research and education program at the South Fork Natural History Museum in Bridgehampton, New York, and the vessel's captain, he was ecstatic about the previous hour's events on board. To everyone's relief, they had nothing to do with a series of minor shark bites reported by swimmers the day before on Long Island beaches, touching off the kind of minor media storm that makes shark experts nervous.

It was July 19th and day three of a fourth consecutive year for the shark tagging program. The morning hit high gear almost immediately when, between calls from reporters at outlets ranging from Channel 5 to the New York Times seeking comment about the shark bites, a five-foot male white shark charged up the chum slick right alongside the vessel. Reacting quickly, Metzger grabbed the nearest fishing rod and reeled a large circle-shaped hook baited with a silvery menhaden right into view. The shark immediately seized it.

The hook held, and five minutes of mayhem later, Metzger's team of two interns, a biologist from the United States National Oceanic and Atmospheric Administration, and a researcher from the New York Aquarium safely secured the approximately one-year-old predator alongside the boat. The tired shark struggled against a rope holding it fast in cool, green water as the scientists rushed to take measurements and attach a satellite tag to its dorsal fin, which would record water temperature and depth of the animal every five minutes for the next 28 days before popping off and beaming its data to a satellite.

Ten minutes later, the irritated shark was released and two giant sweeps of its tail took him completely out of sight as the team hooted and high-fived, out of view of the news choppers looking for sharks but within sight of Manhattan.

Tobey Curtis, a NOAA researcher, holding the shark's tag.

Tobey Curtis, a NOAA researcher, holding the shark's tag.

It was a milestone moment for this collaborative scientific program on juvenile sharks started in 2015 by Metzger and his university buddy Tobey Curtis, a scientist who is the lead researcher for the project and an expert on sharks for NOAA's National Marine Fisheries Service.

While the area's existence as a shark nursery has been known for about 30 years and this stretch of the Atlantic Ocean is now understood to host more juvenile great whites than any other known place on the U.S. coast, nobody had attempted to study the movements of these animals until the program began in 2015. That's when Metzger and Curtis teamed up, christening the effort the Long Island Shark Collaboration. With great white sharks considered vulnerable to extinction by the International Union for Conservation of Nature, they aimed to gather data about how young sharks behave that could inform managers about how to protect the species in one ocean region where their numbers appear to be increasing.

The team's first successful juvenile white shark tagging three years ago attracted the attention of OCEARCH, a non-profit that conducts research on great whites and other large marine predators on its 126-foot vessel. Over the next two years, OCEARCH helped the group tag another 20 juvenile sharks. But 2018 is the first year without OCEARCH's help, and so with a new name and home at the nature center in the Hamptons—and using Metzger's much smaller vessel—2018's first successful tagging was a milestone for the project's next phase. Over three years, the $300,000 effort now aims to capture and tag at least 10 young sharks annually, primarily great whites but also dusky sharks and threshers.

Curtis, from the NOAA, was aboard to affix the satellite tag. The last few years of tracking data had shown the young sharks heading to North Carolina and South Carolina during winter and returning to Long Island in the spring, he said. "With this tracking data we've compiled the last couple years, we have a nice picture now of what habitats they like, the depth of water, distance from shore and also where they go when they leave Long Island waters in the fall," Curtis said. "It's information you can't get without tagging."

First look at the five-foot juvenile great white shark attracted by the swirling chum.

First look at the five-foot juvenile great white shark attracted by the swirling chum.

From previous work published in a 2014 study, Curtis has revealed that populations of great whites are on the rise in the western North Atlantic Ocean. The increasing number of whites likely means more pups coming into the Long Island nursery each year, though it is still a mystery exactly where and when the females give birth.

This data from the Long Island nursery could help managers make better decisions that help shark conservation, Curtis said. "It's less about regulation and more about collecting the data and making it available to decision-makers like fisheries managers and ocean resource managers," he said. "They have to analyze the impact of their activities, so now we can show them [that] juvenile white sharks spend time in these areas."

Another goal of the project is to help scientists understand how sharks are affected by being captured, whether by scientists, anglers, or others. Previous tagging efforts have generally been thought safe and effective, but animal care experts feel it's a good opportunity to study more subtle stress effects—especially on young sharks.

While the shark was alongside the vessel last week, Michael Hyatt, an associate veterinarian and shark researcher with the Wildlife Conservation Society's New York Aquarium, did a quick muscle biopsy for toxicological testing, clipped a section of fin for DNA, and took swabs of the gills, skin, and cloaca to detect the shark's bacteriological make-up. He also drew two blood samples, one at the first moment of capture and again just before release to detect signs of stress by measuring levels of gases and lactic acid. Hyatt was lead author on a recent study of stress from capture and handling in bull and bonnethead sharks, and the idea is to study great whites similarly.

His colleague and head of aquatic animal medicine and pathology at the aquarium, Alisa "Harley" Newton, is also often aboard, and emphasized the importance of this line of inquiry: "We were interested to look at juvenile white sharks—and really juvenile sharks in general—to see how sensitive they were to the stresses of capture," she said.

"In some species you see really big changes between those two blood samples," Newton added. "What we're starting to see with the white sharks is that, with the adults, you don't tend to see a huge swing, but in the juvenile animals, you do. I think it's important to really look at this age class, not just the species, because it's a vulnerable time for them."

De-hooking the captured shark.

De-hooking the captured shark.

Beyond creating a snapshot of stress, the collaboration with Metzger's research program brings deeper understanding. "As a veterinarian I'm not often in a place where I can make these direct links between tagging work and physiological data we're collecting," Newton said. "If I didn't have the satellite data, all I could say is if they're stressed when 'in hand.' It's really important to me to know whether they're recovering from that stress." The blood and biopsy samples are also sent to other researchers to learn even more about shark biology, looking at hormone levels, nutrition, and diet.

Finally, the researchers also have a special short-duration tag they hope to deploy when conditions allow, equipped with an accelerometer and high-definition camera to collect data ranging from feeding activity to tail beat frequency and angle of movement up or down in the water column. Such data could provide an unprecedented level of insight into shark behavior, Metzger believes.

The next day's trip offshore was promising, with a six-foot blue shark, a recently born four-foot great white, and what looked like a tiny smooth hammerhead all attracted to the slick. But the vessel's multiple baited lines invited just one hit all day, very likely from another great white, according to Metzger.

The hook did not set, but the crew remained buoyant and fixed on the mission. At one point Curtis shared one of many favorite Jaws quotes frequently passed around, specifically when Hooper says, "That's a 20-footer."

"That's how I feel every time I see one of these," Curtis said, "that it's one big, beautiful fish."

This article originally appeared on Oceans Deeply, and you can find the original here. For important news about our world’s oceans, you can sign up to the Oceans Deeply email list.