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Nature

Vets Make Tiny Floaties For Sea Dragons Struggling To Swim

author

Aliyah Kovner

Science Writer

clockAug 24 2018, 23:18 UTC

A leafy sea dragon with normal buoyancy. The aquarium's three juveniles need soft rings made from wet suit material to hover in the water like this. Marben/Shutterstock

Three leafy sea dragons are currently floating contentedly through the water column of their Florida Aquarium tank, just as members of the tropical, seaweed-mimicking fish species are wont to do. Yet unlike their wild relatives, the trio is doing so with the help of small neoprene devices that are, in essence, the sea dragon equivalent of children’s pool floaties.

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As the Washington Post reports, the aquarium’s specimens were born without properly functioning swim bladders, a gas-filled organ that allows fish to control their buoyancy and therefore float in the water at their ideal depth without exerting energy.

In their native habitat of the coastal waters off southern Australia, sea dragons hover around patches of sea grass and kelp at depths up to 50 meters (164 feet), feeding on plankton and small crustaceans. With their botanically shaped skin lobes and laissez-faire swimming style, the creatures are masterfully camouflaged to resemble drifting clumps of plant matter.

But these individuals, acquired by the aquarium this April as four-month-old juveniles, were observed exhaustedly swimming to stay off the bottom of their tank and struggling to eat – a clear tip that something was wrong.

Staff veterinarian Ari Fustukjian and his colleagues rushed to diagnose the problem before the fish perished, ultimately performing X-rays on the petite, 13-centimeter (5-inch) critters. The resulting images revealed that their swim bladders were “almost absent”, Fustukjian told the Washington Post. “Somewhere along the normal developmental process, these guys missed the bus.”

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Wanting to give the otherwise healthy sea dragons a chance at survival, Fustukjian devised a neoprene ring that could do the trick; after all, the buoyant wetsuit material is both soft and salt-water durable.

The first test, in June, was apparently a nerve-wracking ordeal. A short length of neoprene had to fitted around the sea dragon’s midsection and then closed into a loop with a stitch. Thankfully, it went smoothly, and the dragons were successfully floating in the water and grazing shrimp in no time.

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"It’s like a pool noodle but seadragon-size," Eric Hovland, the aquarium’s associate curator, told TBO News.

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In the intervening months, Fustukjian and the other vets had to change the floaties several times, as the fish have grown to about 23 centimeters (9 inches) in length. By now, both fish and humans are well acquainted with the process: Fustukjian says he can fit a new device in under a minute and that the dragons are unfazed.

According to the aquarium, the three will transition from limited public appearances to full on stars of the display today. Once they have reached their full sizes in about a year from now, the team will use a 3D printer to create their permanent float-assisting prosthetics.

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[H/T: The Washington Post]


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