Turtles, for the most part, have an omnivorous diet. They feed on small prey of aquatic and terrestrial animals and plants and are mistaking their food for plastic.
In particular, jellyfish are one of the favorite prey of sea turtles. Unfortunately, this preference is a trap for them, as eight million tons of plastic end up in the ocean each year, and the appearance of some plastic bags can be mistaken for these delicious jelly-like organisms.
Also some plastic debris of certain colors can resemble algae, another of the foods eaten by turtles.
The consequences are serious: many marine animals die from ingesting plastic, or perish from being trapped in it.
The green turtle, the most affected
The green turtleChelonia mydas), a species of sea turtle, is most affected in this plastic-for-food mix-up, according to research by scientists at the University of Exeter and the Cyprus Turtle Protection Society.
Through an examination of the guts of the turtles found on the beaches of Cyprus, the investigation revealed that the remains of transparent plastic, or natural colors such as green or black, are the "favorites" of the turtles, over the remains of other shapes and colors.
A deliberate choice, a potentially deadly trap
As the Society for the Protection of Turtles indicates, sea turtles are primarily visual predators, capable of choosing food by size and shape, and in this study we found strong evidence that green turtles show a preference for certain sizes, shapes and colors: black, transparent or green threads and sheets.
According to Professor Brendan Godley, who leads Exeter Marine's research strategy: “Research like this helps us understand what sea turtles eat and whether certain types of plastic are ingested more than others”.
“It is important to know what types of plastic could be a particular problem, as well as highlighting issues that can help motivate people to keep working to reduce overall plastic consumption and pollution.“Continues the teacher.
The research has been published in the journalScientific Reports.
Source: Diet-related selectivity of macroplastic ingestion in green turtles (Chelonia mydas) in the eastern Mediterranean (2019) Scientific Reports. https://www.nature.com/articles/s41598-019-48086-4