Plastic and Sea Turtles
Jellyfish or Plastic bag?
All 7 species of sea turtle are known to have ingested plastic
In our film A Plastic Ocean, turtles are shown to have eaten plastic bags, perhaps mistaking them for jellyfish prey. In fact, 52% of all individual sea turtles are predicted to have eaten plastic. This is particularly concerning for the Leatherback Turtle (Vulnerable, IUCN Red List), which feeds almost exclusively on jellyfish.
Leatherback turtles are visual predators that often hunt in murky waters. Under such conditions, it would be easy to mistake a plastic bag for a jellyfish.
Loggerhead sea turtles are now thought to sense a chemical called DMS to locate suitable foraging areas. While DMS is usually associated with high densities of phytoplankton and zooplankton, we now know that plastic can start to smell of DMS after just a few weeks in the ocean. Could this mean turtles are attracted to areas of high plastic density?
Ingesting a single item of plastic has a 22% chance of killing a sea turtle, rising to 50% after just 14 items. It can take as long as 6 months for a 10cm square sheet of plastic to pass through their digestive tracts.
100% of sea turtle species have now been observed entangled in plastic debris
Roughly 5.5% of turtles are found entangled in some kind of anthropogenic debris, with around 90% of these being already dead. These entanglements cause skin infections, septic processes, and even limb amputations.
Some beaches have been so polluted, that it's thought turtles might not be able to find a suitable space to dig their nests. Hatchlings can even become ensnared in plastic on their way down the beach to the sea.
What's more, microplastics have been found in the sands of turtle nesting beaches. levels were as high as 131,939 pieces per cubic metre at the surface, and averaged 5,325 per cubic metre at the depth of Green and Loggerhead turtle nests. We urgently need to work out the effects could be.
Experts now believe plastic ingestion and entanglement represent two of the biggest threats to sea turtles worldwide.
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