The journey of a Great white shark

The Great white shark (Carcharodon carcharias) is a large predator that has been in the earth’s oceans for over 400 million years, meaning they are even older than dinosaurs. As a shark, the great white has trouble when it comes to relaxing, as the motion of swimming is what provides them oxygen. As a result of not being able to stop swimming you would imagine the distance the shark travels in it’s life time. Until recent technological advances their journeys had never been recorded, but now we are finally able to take a look at where the great whites go, and how far they travel, and hopefully even why.

Scientists have speculated that the shark species in general travels greats distances throughout the worlds oceans during their lifetimes, however these were only speculations as no proof could be provided. Multiple sharks had been tagged before, however the technology at the time would only allow a short while of recording before the tag either fell off or the shark left it’s receivers range.

In March, 2013 a female great white was tagged in Florida by the National Geographic and named Lydia, the team that had tagged her released information on her whereabouts one year after the occasion, announcing that she had travelled over 20,000 miles across the Atlantic ocean and was headed towards U.K. Cornish waters. (Jane J. Lee, National Geographic)

After researchers return Lydia to the sea, her dorsal fin, tracking tag attached, pokes above the waves. Photographed by Robert Snow, Ocearch.

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, west of Portugal. (Greg Skomal, Massachusetts Marine Fishery) Skomal went on to say that there seems to be a single north Atlantic population of blue sharks, and also Mako sharks and is likely the same for some great whites, judging by the route Lydia had taken.

The distance the sharks travel is generally tied to food. In the Pacific Ocean, the movements of great whites are tied to both food and sea lion colonies on the Farallon Islands, near San Francisco and Guadalupe Bay, off Baja California attract great whites from September through to November. (Peter Klimley, University of California) The same sharks then swim to other areas of the pacific ocean, and then later find their way back to the sea lion colonies. This being an example of what is likely the case for the group of great whites in the Atlantic ocean.

Following the journey of great whites is important as we have only just started out in the world of white sharks. This means that we barely know anything about the lives of the white sharks, their daily activities or even why they have them. This ignorance is also a reason why conservation of the mammal has been difficult.
“I think it’s really exciting that they’re starting to get these kinds of tags out there so we can get this information, 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.” (Heidi Dewar, U.S. National Marine Fishery)

2 years ago

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