The plastic ingested makes some sea turtles float
Rescuers believe the plastic debris caused her buoyancy problem – a problem sea turtles face that is sometimes referred to as “floating syndrome.”
In recent years, sea turtles have become closely linked to the plastic pollution crisis, through images of turtles tangled in plastic or with straws stuck in their nostrils. Plastic can also impact turtles like Chex who accidentally ingest plastic and float on the ocean surface, unable to dive down. Without intervention, many of these turtles will die.
Plastic debris is a major threat to sea turtles. Marine biologists estimate that up to 52% of all sea turtles in the world have ingested plastic. Plastic bags, for example, can look like swimming jellyfish, a favorite food of reptiles. Recent research has also revealed that sea turtles are attracted to the smell of plastic debris due to the microorganisms, plants and algae that accumulate on the surface of the plastic.
Once ingested, plastic can wreak havoc on a turtle’s body. Sea turtles are unable to regurgitate anything they swallow, so anything they eat either passes through their bodies or gets stuck. When plastic builds up in their body, it can block the gastrointestinal tract and cause gas to build up. This gas then floats the turtle.
While some turtles can be found by rescuers and rehabilitated, unsaved ones are unable to protect themselves from predation, collisions with boats, dehydration, and exposure to the sun. Due to their inability to dive and a false sense of fullness caused by plastic in their stomachs, turtles can starve to death as well.
Turtles may be able to overcome buoyancy issues on their own if they pass the plastic material, but Stephen Menzies, curator at Reef HQ Aquarium in Australia, notes that they should survive the elements as the material passes.
Research on this problem appears limited and is complicated by the fact that sea turtles can float for a wide range of reasons, such as injuries from boat collisions, infections, and changes in diet. Charles Manire, retired chief of rehabilitation at Loggerhead Marinelife Center in Florida, also notes that sea turtles can voluntarily float when they are about to die to avoid drowning.
Manire further explains that not all turtles whose plastic blocks their gastrointestinal tract will eventually float. “The most common thing we see with plastic in little turtles is blockage of the gastrointestinal tract. In some of these cases, there may also be a build-up of gas, but this is not a consistent finding, ”he says.
Ingestion of plastic can have lasting effects on sea turtles even after the plastic has passed. Fishing lines can damage the intestinal walls, leading to secondary infection. “Even if it doesn’t kill or pass through them, chemicals or other obstructions in the gut can weaken animals and make animals [them] more susceptible to disease or collisions with ships, ”explains Kimberly Warner, Senior Scientist at Oceana.
The exact extent of this problem is unknown. Buoyancy issues caused by ingesting plastic affect about “10 percent or less” of cases at Turtle Hospital, a sea turtle rescue and rehabilitation center based in the Florida Keys, says Bette Zirkelbach, director of the hospital.
“Flotation abnormalities are relatively common, but secondary to the ingestion of plastic, it’s not too common,” said Terry Norton, director and veterinarian of the Georgia Sea Turtle Center, a turtle education and rehabilitation center. marines.
Menzies notes regional differences in the magnitude of buoyancy issues caused by ingesting plastic. “My observation is that in the more developed areas of the Australian coast, where there is more plastics in the ocean, local populations are more affected,” he says.
Manire says he sees juvenile turtles affected by ingesting plastic more often than adult turtles in his area. “It takes a big enough piece of plastic to block the intestines of a bigger turtle and most of the plastic we deal with is very small,” he says. “The most common problem we see in the largest green turtles in Florida is buoyancy issues caused by gas build-up in the intestinal tract, but there is rarely evidence of marine debris involved.”
Experts believe that young turtles are more likely to be affected by ingesting plastic because of their smaller body size and the increased likelihood of ingesting debris. Young sea turtles travel on currents and spend their first years on the high seas, but these currents are now home to large amounts of plastic, according to a study from August 2021. The authors say the location of juvenile turtles on the high seas makes difficult to assess the impacts of man-made threats.
Buoyancy issues are more difficult to detect in young turtles because they naturally spend most of their time on the surface, while older turtles feed on the bottom, Zirkelbach explains. Much of the lightweight plastic also floats to the surface, where young turtles – less selective eaters than older turtles – might accidentally eat it. A 2020 study found plastic in the gastrointestinal tract of more than 90 percent of post-hatch sea turtles examined.
Experts say buoyancy issues caused by ingesting plastic may be more common than currently thought due to the difficulty in documenting this issue. “There are a lot of turtles out there that we never see,” says Zirkelbach.
“Plastic, unfortunately, does not stay local and impacts on hatchling turtles are likely to be high but unrecorded as they are far offshore,” adds Menzies.
In Chex’s case, rescuers say it’s difficult to definitively correlate his buoyancy issues to the ball, as they were also treating him with diet and medication the moment he passed the ball.
“Determining the underlying cause of buoyancy can be difficult. Diagnostic imaging, such as x-rays and CT scans, is great for visualizing gas in the GI or an impaction or obstruction, but not picking up all foreign objects, ”a Clearwater Marine Aquarium spokesperson said. “The metal shows up very clearly, but plastics and other soft materials can blend into tissue, making diagnosis difficult.”
“Most of the time, it is diagnosed when they pass pieces of plastic in their stool. Sometimes in larger turtles [it’s diagnosed] by endoscopy or surgery or if the turtle dies, then at the autopsy, ”says Norton.
Rescued turtles face varying results. Some turtles, like Chex, can pass the plastic and be released into the wild. Others succumb to their injuries. The Turtle Hospital recently rescued a post-hatch sea turtle with buoyancy issues. Once taken care of, the turtle began to show positive signs: it passed pieces of plastic and began to eat again. But despite the best efforts of the rescuers, the turtle died. An autopsy showed that the intestines and intestines of the turtle were filled with plastic.
Buoyancy caused by ingesting plastic may not be the most pressing threat to sea turtles, but it illustrates one of the many ways plastic can harm marine life.
Zirkelbach thinks it’s important for people to have hope when thinking about the impact of plastic debris on sea turtles: “I think we are an intelligent species and we need to be committed to protecting our oceans and of our planet. [Reducing] single-use plastic is one of them.