Scientists at University of Miami's RJ Dunlap Marine Conservation Center (RJD) have successfully tagged and released a 15-foot female great hammerhead off the coast of Florida – likely one of the largest ever studied by satellite. Sure, sharks are tagged all the time, but what might come as a surprise is that great hammerheads (Sphyrna mokarran), listed as endangered by the IUCN, are extremely sensitive animals, which makes working with them very difficult. 

This is something the RJD team has studied in great detail and doesn't take lightly. "Great hammerhead sharks are incredibly vulnerable to capture stress, and therefore we are very careful about how we handle them," says team member David Shiffman.

On more hardy species like bull and nurse sharks, RJD staff perform an entire work-up (this means taking important measurements, a quick blood sample, testing the shark's reflexes and when appropriate, putting on a small tag) in an impressive three minutes. But hammerheads receive an ever quicker work-up to compensate for any extra stress the animal may experience.

"Hammerheads are extremely fast swimmers," explains Dr Austin Gallagher, who has done extensive work on reducing stress in sharks. "They're like the Ferraris of the ocean, so it makes sense that they expend a lot of energy when they're on a line – even after release. We want to make sure that fishing practices are sustainable and that we're doing all we can to improve survival." Even for an experienced researcher like Gallagher, seeing such a healthy great hammerhead in Florida waters was extremely exciting. "Hammerhead sharks, specifically great hammerheads, are ghosts of the ocean," he says. "They are rarely seen these days, and when you do its a fantastic, memorable, and often shocking experience." 


The shark's satellite tag is now broadcasting loud and clear, telling RJD that their careful work has paid off and the shark is doing well. Its data will help us better understand the movements of these incredible fish so that we may better protect them in the future. 

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No poles in sight: Dr Austin Gallagher brings the shark to the boat for a work-up. This is done gently by hand to reduce stress on the animal.
Special circle hooks are used to prevent any injury. Image: RJ Dunlap

You'll soon be able to follow the shark on the team's website, so keep a watchful eye. To learn more about shark tagging and RJ Dunlap, check out their Facebook page!

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Top header image: BlueRidgeKitties/Flickr