Artificial fin put on Hofesh the turtle.
Freedom the turtle - or Hofesh, as he's known in Hebrew - lost two flippers on his left side four years ago after he was entangled in a fishing net, leaving him immobile, unable to lift his head above water to breathe and in danger of drowning.
But now, thanks to an innovative Israeli design student, some very strong glue and extremely resilient plastic, he can swim, breathe, and hopefully breed, no less important for his species, the endangered green sea turtle.
For years after he was rescued, Hofesh was unable to swim, and only able to lie in a shallow water tank for fear of drowning. His carers at the Israel Turtle Rescue Center changed that when they first experimented with a diver's flipper, fixing it to his side in an effort to provide Hofesh with much needed stability.
The improvised fin proved unwieldy and Hofesh's carers began a long process of trial and error with various designs that had some success. Progress became more rapid when industrial design student Shlomi Gez heard of Hofesh's plight leading to a dual fin design that he said was based on aeronautics company Lockheed Martin's supersonic F-22 'Raptor' jet fighter.
While Hofesh retained his steady, measured pace, the design did provide much needed stability. Gez later redesigned the fin attachment, and on Wednesday (April 9), Gez and centre manager Yaniv Levy pulled Hofesh from his tank, dried him down and fixed a new hydro-dynamic streamlined prosthetic fin to Hofesh's carapace.
"It's based on fish biomimicry," said Gez, who made the fin from polypropylene, a thermoplastic polymer that is unusually resistant and long-lasting. "In fish, the back fin of the fish it does just balance," he explained, and that shape stops Hofesh from tipping over when he gets agitated.
"When he's getting to be a bit stressed, panicking or something, he's hitting on one side, with what he's got, with only the front fin, and then he's tilting his head ninety degrees and then he can't lift up the head to breathe and he starts breathing water and he's panicking and he's starting doing somersaults and going crazy all around," said centre manager Levy. Handlers once had to resuscitate Hofesh after a similar incident, he added.
Finding the perfect solution to Hofesh's amputated limbs was a work-in-progress, Levy said. "It's a biological material, the carapace, and it grows, it has to breathe, so all the time we have to find different ways to improve the method and we didn't finish yet. There's still a long way but it's getting better and better and I can say today that when he has the fins on him, he's much calmer, he doesn't get into panic, he doesn't have any problems anymore."
As Hofesh could drown if the fin came off, he can't be released back to the sea, but Levy said he was hopeful he could be used as breeding stock. Now that Hofesh can swim in a deeper tank, he's been placed in a tank with Tzurit, a blind turtle that lost her eyesight when hit by a boat propeller and also can't be released back to sea. Both turtles, in their twenties, are considered 'young,' as their species has an lifespan of over 80 years. They reach sexual maturity in their thirties.
Green Sea Turtles are listed as an endangered species globally, and are considered 'critically endangered' in the Mediterranean Sea. The Israel Turtle Rescue Center treats around 50 turtles a year, and most are later released. Their injured are often due to encounters with boats, jet skis, and fishing nets and hooks.
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