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Ultrasound helps save sea turtles from fishing nets

Researchers can use portable ultrasound on boats to detect and treat gas emboli in sea turtles, significantly improving their rehabilitation. These ancient mariners, gracing our oceans for over 100 million years, are now struggling for survival.

Six out of seven species are endangered, and human activities carry a heavy responsibility. While plastic pollution and habitat destruction often steal the headlines, a lesser-known threat lurks beneath the waves: decompression sickness, also known as “the bends.”

Underwater life of sea turtles

Sea turtles, like many marine creatures, are adapted to life underwater. They can hold their breath for extended periods, diving to depths where the pressure is much higher than at the surface. However, this ability to withstand pressure becomes a liability when they are unexpectedly brought to the surface.

When a sea turtle is caught in a fishing net, it ascends too quickly. Its body can’t adjust fast enough. The rapid ascent decreases pressure, causing gases like nitrogen in its tissues to form bubbles. This is similar to opening a soda bottle, where a sudden pressure drop makes the carbon dioxide fizz and bubble up.

These gas bubbles can obstruct blood vessels, damage tissues, and disrupt organ function. The effects can range from mild discomfort to severe illness, even death. In turtles, symptoms of decompression sickness might include lethargy, disorientation, buoyancy problems, and visible bubbles under the skin.

Ultrasound impact on sea turtles

Veterinarians are teaming up with fishers in a unique collaboration. Armed with portable ultrasound machines, they examine sea turtles accidentally caught in fishing nets.

“Veterinarians can examine whole-body MRI or X-ray scans and find specific bubbles in a variety of different organs,” explains Katherine Eltz, a doctoral student at the University of North Carolina at Chapel Hill.

“The benefit of ultrasound is that we can see bubbles flowing through vessels or stationary in tissues. The portability of ultrasound means that it can be brought onto fishing boats, which we took advantage of to collect half of the data used in this project.”

Researchers take ultrasound images in real-time, directly on fishing boats. They can observe gas bubbles in the turtles’ hearts, livers, and kidneys. This method allows scientists to assess the severity of the bends in each turtle. The experts can then determine the best course of action.

Brightness as a barometer

One of the most exciting findings of this research is the development of a new way to quantify the amount of gas in a turtle’s body. “The brightness from the ultrasounds taken from the groups is a valuable quantitative metric to separate each ultrasound by grade,” Eltz explains.

In other words, brighter ultrasound images mean more gas bubbles. More gas bubbles mean worse decompression sickness. This simple yet powerful metric has the potential to transform how veterinarians treat sea turtles with decompression sickness.

Veterinarians can quickly gauge the severity of the condition using this metric. This rapid assessment enables them to make informed decisions about the turtle’s care. Depending on the findings, they can determine if a turtle requires specialized treatment or can be safely released.

A global problem with local solutions

Decompression sickness in sea turtles is a widespread problem, affecting these animals in oceans around the world. The research conducted by Eltz and her colleagues, incorporating data from diverse locations like Brazil, Italy, and Spain, highlights the global nature of this issue. This is largely due to the vast migratory patterns of sea turtles and the ubiquity of commercial fishing activities.

Addressing this problem requires a coordinated global effort. Fortunately, the response to this challenge has been met with international collaboration. A collaborative approach is essential for developing effective conservation strategies that can be implemented on a global scale. They can ultimately protect these ancient mariners for generations to come.

The future of turtle care

The work of Eltz and her colleagues is still ongoing, but the results so far are promising.
The development of the ultrasound brightness metric marks a significant advancement in diagnosing and treating decompression sickness in sea turtles.

This metric enhances our capacity to accurately identify the condition in affected turtles. It also improves the effectiveness of the treatments we administer. This breakthrough aids in the precise assessment and management of the health issues sea turtles face when they suffer from decompression sickness.

“The largest task still at hand is to work towards standardizing the acquisition of the ultrasound data collected for this project,” Eltz says. “Now, I can work with veterinarians to help adjust their methods, including improved image processing to standardize the data in post-processing.”

With ongoing research and collaboration, we can anticipate a future where sea turtles receive better protection from the hidden dangers beneath the waves. Continued efforts will enhance our ability to safeguard these marine creatures.

Together, we can develop more effective strategies to shield sea turtles from unforeseen threats in their natural habitat.


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