Bottle Caps, Halloween Toy and Other Plastics Found Inside Dead Sea Turtles in the Mediterranean

Researchers have discovered a variety of large plastic pieces in the guts of dead sea turtles found in the eastern Mediterranean. Some of these plastic items include bottle caps and a Halloween toy in the shape of a witch finger.

A team led by the University of Exeter and the North Cyprus Society for the Protection of Turtles (SPOT) examined 135 loggerhead sea turtles (Caretta caretta) that had died in North Cyprus, which has several nesting and foraging sites on beaches in the area. According to the study, many sea turtle deaths in the area are because of bycatch, and strandings also occur that may be related to interactions with the fisheries.

The researchers collected dead sea turtles from 2012 to 2022 and examined their guts for debris, including macroplastics, or plastic pieces larger than 5 millimeters.

In total, researchers found 492 macroplastic pieces in 42.7% of the turtles, and one individual turtle contained 67 of those macroplastic pieces. They published their findings in the journal Marine Pollution Bulletin.

Overall, the researchers noted that the plastic pieces ingested tended to be rectangular, sheetlike, hard or foam texture and clear or white in color. The most common types of macroplastics found were polypropylene, polyethylene and polyamide.

The researchers also recorded findings of plastic-like debris, including elastic and rubber. In one turtle, they found a witch finger toy made from rubber.

“The journey of that Halloween toy — from a child’s costume to the inside of a sea turtle — is a fascinating glimpse into the life cycle of plastic,” Emily Duncan, from the University of Exeter’s Centre for Ecology and Conservation at the Penryn Campus, said in a statement. “These turtles feed on gelatinous prey such as jellyfish and seabed prey such as crustaceans, and it’s easy to see how this item might have looked like a crab claw.”

According to the study authors, these findings could further support sea turtles as a bioindicator species, although more studies are needed. A bioindicator species is one that reveals changes to the health of an environment, such as the often-cited example of a canary in a coal mine.

As Brendan Godley, a professor at the University of Exeter who leads the Exeter Marine research group, explained, “Much larger sample sizes will be needed for loggerheads to be an effective ‘bioindicator’ species, and we recommend studies should also include green turtles — allowing a more holistic picture to be gathered.”