Studies Say Sea Turtles Think Plastic Smells Like Food
Although sea turtles have been chomping down on plastic bags for years, scientists didn't know why -- until now.
Plastic bags may smell like a tasty treat because of the bacteria and algae that accumulate on them.
Once plastic has been released into the ocean, microbes, algae, plants and tiny animals start to colonize it and make it their home. This creates food-like odors, which have been shown to be a magnet for fish and possibly sea birds.
New research suggests sea turtles are attracted to plastic for the same reason.
The researchers piped airborne odors into the air above a water tank and recorded the turtles' reactions with cameras.
The animals responded in the same way to odors from conditioned plastics released into the air as they did to food such as fish and shrimp meal.
"The turtles responded almost identically to the smell of their food as they did to the smell of a plastic bag that had been soaked in water," according to Matthew Savoca, a postdoctoral research fellow at Stanford University's Hopkins Marine Station and one of the study's authors. "In fact, the turtles kept their noses out of the water three times as long to smell the plastic bags compared to control smells," he added.
The research reveals greater implications on how increasing amounts of plastic pollution will be harmful for turtles and other marine animals, including whales, seabirds and fish.
Ingesting just over a dozen pieces of plastic can kill turtles. Young turtles are particularly vulnerable because they tend to swim in currents where loads of plastic accumulate.
Once a turtle swallows plastic they are unable to throw it back up. As a result, most of the ingested plastic gets stuck in the turtle’s gut and limits its ability to absorb and digest food.
The findings open up new avenues for research to protect the marine animals that are threatened by plastic debris in the sea, mostly through entanglement and ingestion.