Discarded tires in the oceans are trapping hermit crabs, with no way out

Discarded tires in the oceans are trapping hermit crabs, with no way out

Hermit crabs are finding their way into discarded tires in the ocean — and they can’t get out, a new study from Hirosaki University found.

The concave interior of a car tire can trap hermit crabs that go there in search of food and shelter. The study refers to this phenomenon — when marine animals get caught in human litter, such as fishing nets — as “ghost fishing.” Atsushi Sogabe, first researcher on the study and associate professor at Hirosaki University, initially noticed this during a 2012 survey of Mutsu Bay in Japan. While monitoring pipefish along Mutsu Bay, he saw several shells in a discarded tire, some belonging to hermit crabs.

“I thought that the hermit crab that had invaded the inside of the tire could not escape due to the recurved inner structure of the tire and consequently die,” Sogabe said in an email to CNN. “I wanted to prove this to myself.” The hermit crab shells found in this survey were heavily damaged, and researchers suggested this was a sign of cannibalism or competition for lodging among hermit crabs that were stuck.

Through experiments in an aquarium and the ocean, the researchers studied whether hermit crabs would be able to escape the tires. Over the course of a year, scientists collected and released the crabs monthly, observing nearly 1,300 hermit crabs that were trapped in the tires. (Don’t worry — the hermit crabs were only used once and released near where they were collected.) None of the hermit crabs that found their way into the tires could escape. “The significance of this study is that it shows that not only the chemical and physical properties of the tire, but also the shape of the tire can have a negative impact on marine life,” Sogabe said.