National Geographic News
Photo of Lydia the shark.

Scientists get ready to attach a tracking tag to a great white shark nicknamed Lydia.

PHOTOGRAPH BY ROBERT SNOW, OCEARCH

Jane J. Lee

National Geographic

Published March 11, 2014

Ever since researchers tagged a great white shark nicknamed Lydia off Jacksonville, Florida, in March 2013, they've been keeping a close eye on her. Their vigilance was rewarded this past weekend when the 14-foot (4.4-meter) fish became the first great white observed to cross the Atlantic Ocean.

Researchers had suspected great whites could make such a journey, but none had previously been documented doing so, says Heidi Dewar, a fisheries research biologist with the U.S. National Marine Fisheries Service in La Jolla, California.

Although great white sharks aren't the only aquatic species to make such long-distance trips, this discovery is changing the way researchers think about the iconic animals, from the ways in which their populations interact to potential conservation strategies.

Lydia is now just east of the Mid-Atlantic Ridge—an underwater mountain chain that threads north and south through the ocean—and is headed toward the U.K.'s Cornish coast. Researchers consider crossing the ridge to be the official point at which one passes into the eastern Atlantic.

The shark now also holds the distinction of traveling the farthest of any known great white. So far, Lydia has swum about 20,000 miles (32,187 kilometers), including meanderings along the U.S. East Coast before she struck out for Europe. Ocearch, the organization that developed the method used to capture and tag the great white, displays a real-time track of the shark on its home page.

This champion swimmer blew past the previous record holder, a female that swam from South Africa to western Australia and back—crossing the Indian Ocean both ways—for a total of 12,427 miles (20,000 kilometers) in 2004.

Photo of Lydia the shark.
After researchers return Lydia to the sea, her dorsal fin, tracking tag attached, pokes above the waves.
PHOTOGRAPH BY ROBERT SNOW, OCEARCH

"We're really just starting out in the world of white sharks," says Greg Skomal, the senior fisheries scientist at Massachusetts Marine Fisheries who tagged Lydia. Tracking such huge predators wasn't feasible until recent advances in technology.

Lydia's satellite tag transmits location data every time the unit, attached to her dorsal fin, rises above the ocean's surface. Previous tags, known as archival tags, stored all their information until researchers could retrieve the unit, download the data, and re-create the shark's track. (See "Shark Tagging & Tracking: Separating Fact From Fiction.")

One Big Family?

Scientists have traditionally considered great white populations in the Mediterranean and off the U.S. East Coast to be distinct. But they have also occasionally seen great whites off the coasts of Europe and the Azores (map), west of Portugal, says Skomal. Looking at data from sharks like Lydia, he says, "you start to think, this may all be one big population."

"Indeed, that's what's panned out when they've looked at [transoceanic movement] in other species," he adds. There seems to be a single North Atlantic population of blue sharks, for example. "I think the same can be argued for the mako." (See "Record-Breaking Mako Shark Tips Off Conservation Debate.")

It could very well be that other great white sharks journey across the Atlantic, Skomal says. Lydia just happens to be the first one researchers observed making the trip.

Map of Lydia the shark's travels.
NG Staff

Follow the Food

Why did Lydia decide to head to Europe? Likely for the banquet at various stops along the way.

On March 7, tracking data showed her swimming north along the Mid-Atlantic Ridge. "She's not diving down to the ridge," Skomal says. She's just swimming above it like an animal walking along a fence.

Lydia knows the feature's there, Skomal says, likely picking up on magnetic anomalies. But the area is also rich in feeding opportunities, which is probably why she spent time wandering above the underwater peaks.

In the Pacific Ocean the long-distance movements of great whites are usually tied to food, says Peter Klimley, a great white shark expert at the University of California, Davis. Seal and sea lion colonies on the Farallon Islands, near San Francisco, and on Guadalupe Island, off Baja California, attract great whites from September through November. (See a video of a great white shark going after seals.)

The sharks then swim out to the middle of the Pacific. Researchers are still trying to figure out what they do there, but the sharks then come back to the same coastal marine mammal colonies, Klimley explains.

Return Appearance

As to whether the U.S. East Coast will ever see Lydia again, Dewar thinks there's a good chance she'll return. "That seems to be the typical pattern for females," she says. They'll give birth, then they "go off and forage, and travel pretty wide distances for two years or so, and then they come back."

But, Dewar cautions, "we don't have that many tags on large females, so there's always the potential to be surprised.

"I think it's really exciting that they're starting to get these kinds of tags out there so we can get this information," she says. "The large females are a really important part of the population, and until you know what's going on, it's hard to develop conservation strategies to protect them."

Follow Jane J. Lee on Twitter.

78 comments
John Russell
John Russell


The sharks had become so aggressive she had to get out of the water....


The Florida Dive boat operators were trying to skirt the regulations. Read about the investigation that led to their arrests.

Protect and save sharks and divers. http://chn.ge/1qjxitC


Jolene Evans
Jolene Evans

great to see the wonderful job you are doing...All our Premier of our state in Australia wants to do is cull them

Betty Pinchefsky
Betty Pinchefsky

Hope Lydia keeps swimming for years!  We will watch her go back and forth

Jeff Killer
Jeff Killer

some people say they are going to catch lydia so keep an eye on her for me ok

Jeff Killer
Jeff Killer

some people say they are going to catch lydia so keep an eye on her for me ok

Sharyn Ryan
Sharyn Ryan

Great subject and great story so far, keep it up dudes..

J. Watkins
J. Watkins

Absolutely amazing. Thanks, Nat Geo, for making this available to us!

Mukund More
Mukund More

thanks for keeping a valuable observations 

Larry Milne
Larry Milne

Are you following sharks to save them, or to kill them ? Fishermen will be tracking you!

Dana Diotte
Dana Diotte

That is very cool. I love that the scientific community is debunking the stereotype of sharks. Unfortunately Australia just took a step backwards in protecting this awesome ocean predator.

There are a few web mapping applications that track various sharks in real time. I believe this is one that tracks Lydia as her name is in the list. http://www.ocearch.org/#SharkTracker

Ali Allam
Ali Allam

waiting to hear about the rest and end of the important trip.

Annie Beasley
Annie Beasley

Great job on the successful tagging and tracking! I used to live in Jacksonville, FL and surf near where this white shark was reported. It sure made me think twice about the fins I see in the water now. I love to read about the continued research on these sharks... thanks for your hard work.

nicholas sluggett
nicholas sluggett

because in Australia we are not allowed to kill any shark that is over 1.5 metres long, all the big shark species will just keep spawning and soon there will be masses of sharks everywhere 

Vinaya Kumar
Vinaya Kumar

Fascinating!! Would love to follow this story!!

Nikki Stokoe
Nikki Stokoe

I love reading about all animals and this is just one fascinating article!

Bill Rob
Bill Rob

Why didn't they attach a camera to the shark?  They could have made her a Honorary National Geographic Photographer and given her a 'Cover' as the first non-human to have her pictures appear on the cover of the Magazine.

Bruce Beattie
Bruce Beattie

Fascinating story !!! More to come. I'll be watching.

Fawad Haider
Fawad Haider

Wonderful story! Congratulations to the team on this achievement.

Nicole F.
Nicole F.

I'm concerned that once commercial fishermen know where sharks go they will be further endangered. Perhaps their mysterious and unknown routes has helped keep them alive this long. Once this data is available - what protects them?

The organization tackling this has, in my view, a responsibility here. Especially as there mission is to help preserve them.

Jamie Force
Jamie Force

Thanks Nat Geo! I love the stories you post!

David Yarrow
David Yarrow

What a shame our horrid and backward government in Australia feel the need to kill these majestic creatures to score votes from the ignorant. Shame on us.

Big Bill
Big Bill

Great job folks and take great care of my favorite " fish ".

Vlad Varlan
Vlad Varlan

This is quite something, I never thought great whites could travel that long.

Jose Mendez
Jose Mendez

Ever since researchers tagged a great white shark nicknamed Lydia off Jacksonville, Florida, in March 2013, they've been keeping a close eye on her. Their vigilance was rewarded this past weekend when the 14-foot (4.4-meter) fish became the first great white observed to cross the Atlantic Ocean.

Fred Wells
Fred Wells

Only one reason Lydia is coming towards us - Police Chief Brodie is on holiday in the UK...

Linda Nemiroff
Linda Nemiroff

Very interesting and exciting article.  Sharks, I believe are misunderstood.  They are one of many predators of the ocean and should be respected because of that.   Check out the waters before swimming, sailing or scuba diving. 

Thank you Nat Geo for another eye opening article about our wildlife.

Ken Sullivan
Ken Sullivan

great article. Amazing to find out how far they can travel. 

Daniele Arnaud
Daniele Arnaud

I watched a video from Australia where they start to kill sharks to protect people swimming at popular beaches. They say that they have to be killed to avoid people to be injured or killed by white sharks. So far people are the biggest predators in my opinion.

Paul Gann
Paul Gann

I believe that I saw the tagging process on the Nat Geo several months ago. Interesting journey for the shark. It would be very interesting if she returns to the US coast once again. 

Roy Mills
Roy Mills

I had wondered if she had gone along with the Gulf Stream, but obviously not. She could meet up with the remnants of it though off The S.W. corner of England. The rest of her journey will be very interesting indeed.

Henry B.
Henry B.

How long will the tracking operate

Bill Robertson
Bill Robertson

Lydia you wont like it over here in UK waters to cold,though we do have Basking sharks..

Ryan DeYonker
Ryan DeYonker

Hey Lydia, tell your friends out there to stay away from Western Australia... especially Perth! They've recently started culling large sharks. It's kind of like conservation, but the opposite. People can be quite desperate when they're afraid.

Michael Hurne
Michael Hurne

Great article but a maybe posted a day too late? Looking at the map for all the sharks, wouldn't it be safe to say Rizzilient is the first recorded as crossing the Atlantic now?

Dwayne LaGrou
Dwayne LaGrou

I was just curious if she had any companion Remoras attached to her, And do they stay attached all the time or do they detach and swap "Parent" sharks every once in a while? It is quite rare to see a shark pictured in the water without one or two tagging along for a free meal!

Thanks Nat. Geo. for an interesting article, And keep up the good work!!!

Kimberly Burtnyk
Kimberly Burtnyk

I was shocked to see how close she got to the shore in Newfoundland! (I have a friend who lives there!) This work really helps to 'humanize' these magnificent, misundertsood animals (which I have always loved and admired and respected). There she is just following the food, minding her own business, crusin' the wide open sea. On the other hand, now I worry about her  :-(   I hope she has had (and continues to have) lots of babies. I wonder how often they find a mate? It seems like a lonely life. Safe travels, Lydia.

Deddy Hadinata
Deddy Hadinata

Safe journey Lydia and keep away from fishing boats, or your fins will end up on a plate in a chinese restaurant!

jeff verkouille
jeff verkouille

@Bill Rob The mid-Atlantic tends to be quite murky; a camera on a more tropical shark, such as a Whale shark, might be a fine idea however.

jeff verkouille
jeff verkouille

@Nicole F. White sharks are a protected species and not commercially fished.  Also fuel costs make fishing the mid-Atlantic unprofitable.

David Yarrow
David Yarrow

@Daniele Arnaud

Yes, Our government in Australia is an embarrassment. They Kill our sharks to assist the tourism market while at the same time approve the dumping of toxic dredging on the Great Barrier Reef knowing that it will do irreversible damage. Now they want to unlock tens of thousands of heritage listed old growth forests for clear felling and and and the list of human and environmental vandalism goes on and on. Very sad indeed.

Jane Lee
Jane Lee expert

@Dwayne LaGrou  I'm not sure about the remoras, but I can see if one of the researchers who worked on Lydia knows.

Lindi Hall
Lindi Hall

well said. I hope she has a very long and very lonely life. Better for her to be left alone than bothered by us.

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