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Decompression Sickness in Sea Turtles

Did you know that sea turtles can get decompression sickness?

One of the biggest threats to turtles is getting caught in fishing nets. And that’s partly because of the high chances of getting decompression sickness (DCS) as they are brought up to the surface by fishing boats.

Why do Sea Turtles Suffer from Decompression Sickness? 

Under normal conditions, during diving turtles not only have the ability of being bradycardic but a shunt system in their heart means that blood does not go into the lungs. This prevents the transfer of nitrogen into the blood which would happen in anything more than atmospheric pressure.

When the turtle is caught in a net, the resultant stress and activity mean the animal becomes tachycardic and the shunt no longer functions. Atmospheric pressure forces nitrogen into the bloodstream and organs. As the turtle is brought to the surface, the pressure decreases, and the gas comes out of solution. Bubbles are formed, causing blockages (embolisms) and potential damage to organs.

How do we Diagnose DCS in Sea Turtles?

Pioneering work by colleagues of Wildlife Vets International at Fundacion Oceanográfic confirmed the reality of decompression sickness in turtles during research into turtle bycatch by fishermen off the coast of Valencia in Spain. These gas bubbles can be seen on X-ray, CT scan and ultrasound once you know what you are looking at.

The graphic shows x-rays of a normal turtle, drowned turtle and one with extreme gas embolism. 

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How Can We Treat Sea Turtles with DCS?

The first turtle known to be suffering from decompression sickness was cured in an autoclave!

Once the turtle was stabilized and breathing on its own, a spectacular piece of lateral thinking by the team at Fundacion Oceanográfic saw them squeeze the young loggerhead with gas embolisms into their autoclave. 

When it comes to DCS, there are no protocols for any species other than humans, so the team followed those as they tried out this homemade hyperbaric treatment using pure oxygen. The results were promising; after five hours the turtle had reabsorbed most of the gas. For the first time, reality of decompression sickness in turtles had been demonstrated.   

Fortunately, the team publicised their findings widely, and further up the Spanish coast Fundaçion CRAM, with the help of turtle vet Tania Monreal (IZVG), had their own decompression chambers built. 

In this clip, Tania tells TV vet Emma Milne about decompression sickness in turtles as they stand by CRAM’s decompression chamber. This one is big enough to accommodate the largest of loggerheads! 

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D. Garcia Parraga first presented the Fundacion Oceanografic team’s findings at the IAAAM 2013 conference. Click HERE to read.

It was subsequently published in Diseases of Aquatic Organisms, October 2014 HERE.

Find out how you can support WVI’s Turtle Team and other wildlife vets controlling disease and saving species HERE.