Tires left behind in the ocean are becoming deadly traps for hermit crabs who may resort to eating each other to survive.
According to a Japanese University study, the bottom-feeding Arthropods can crawl into the tire’s concave interior, but cannot escape.
Atsushi Andogabe and Kiichi Takatsuji, biologists, discovered hundreds of hermit crab shells in a discarded tire at Mutsu Bay in Aomori Prefecture.
Some still had occupants but many more were damaged and discarded—a sign, Sogabe and Takatsuji believed, that the crab inside had fallen victim to cannibalism or violent competition for food or shelter.
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Tires left in the ocean can become deadly traps for hermit crabs. They can climb into the concave structures, but can’t escape. Researchers discovered that nearly 1,300 crabs were trapped in six tires in Mutsu Bay.
To test their theory, six car tires were submerged in water about 25 feet deep in a bay. They returned once a month to determine if any hermit crabs had been trapped.
They found 1,278 hermit crabs in the six tires over the course of a single year.
Sogabe said that Takatsuji and Takatsuji release trapped crabs at 160 feet or less from the tires at each monthly interval.
They claimed that if they hadn’t, the crustaceans would have died from starvation and cannibalism.

The extensive damage to the shells (above), suggests that the inhabitants were involved in violent fights for food and shelter. It is possible that they were even eaten by other crabs.
In a separate experiment, Sogabe and Takatsuji also placed a car tire in a large aquarium and added hermit crabs—some inside the tire, some outside.
Six trials lasting 18 hours each confirmed that the crabs can climb into the wheel.
Hermit crabs are found in scavenged sea snail shells. When they die they release a chemical signal to other species that a new home is available.
This attracts more crabs to the garbage that has trapped them.

Hermit crabs are an important part of marine ecosystems. They serve as both prey for larger animals such as shorebirds, and as scavengers. They keep the seabed clean, turn and circulate soil, which helps plants grow.
Ghost fishing is a term that describes the trapping of marine life in discarded fishing nets or other ocean litter.
However, tires pose a greater danger than nets, Takatsuji and Sogabe note.
The researchers published a report in Royal Society Open Science that stated that fishing gear can ghost fish for up to three years. This depends on the type of gear, its material, and the environment it was discarded in.
“Because of their simplicity, temporal persistence, and robustness, tires might ghost fish hermit crawls for a considerable longer time.”
Hermit crabs are an important part of marine ecosystems. They serve as both prey for larger animals, such as shorebirds, as well as scavengers. They clean the seabed and turn and circulate the soil, which aids plants to grow.
The authors wrote that ghost fishing’s effects on the populations and any cascading effects on coastal communities and ecosystems are unknown.
Ghost fishing may have an impact on coastal ecosystems due to the important role that hermit crabs play in coastal food webs as both prey species and scavengers.
In Florida, two million cars were deliberately dumped into the Atlantic in 1970s in order to create an artificial reef that would support marine life.
However, hurricanes and tropical storms continued to spread the tires too far apart, so divers have had their tires retrieved, NPR reported in 2007.

After being trapped in plastic, 570,000 hermits were killed off the Cocos Islands (Keeling) Islands and Henderson Island in Pacific.
This is not the first instance of plastic refuse being fatal to hermit crabs.
Researchers from the Natural History Museum in London found that, on just two remote islands, more than half a million hermit crabs had died after being trapped in plastic bottles and other trash.
That’s equivalent to one to two crabs per square meter of beach – a significant percentage of the entire island’s population of hermit crabs.
According to research published last year by the Journal of Hazardous Materials (JHM), researchers found 508,000 trapped crabs in the Cocos Islands (Keeling) Islands of India Ocean and 61,000 in Henderson Island in Pacific.

A hermit crab in a piece of plastic pipe. Some crabs can use the litter to create a new home, but many others become trapped and die.
Alex Bond, conservationist and author of the book, believes that the problem will be widespread on islands around the globe.
‘The problem is insidious,’ Bond told DailyMail.com previously.
He said that one crab is all it takes to attract other crabs.

Hermit crabs live in scavenged sea snail shells and when they die, they release a chemical signal to others of their species that a home is available. This attracts more birds to the trash that traps them.
The team consisted of Bond and scientists from University of Tasmania’s Institute for Marine and Antarctic Studies and the Two Hands Project, a community marine pollution organization.
They discovered that plastic pollution on the beaches of islands creates a barrier for crabs to use and traps them.

The Cocos Islands and Henderson Island are largely uninhabited, but plastic waste is washes onshore every day. Researchers believe the same plastic-filled beaches are found around the globe.
Although the islands are uninhabited they do have plastic trash such as soda caps, detergent bottles and other plastics.
Tires pose a risk to crabs and marine life in other ways—including as a major contributor to the microplastics that wind up in the world’s waterways.
As rubber wears down, tiny bits of rubber become loose and end up in the ocean.
Once they are in water, they can be ingested by marine animals and can have a negative impact on their digestive system.
A microparticle in one creature could end up in the system a predator hunts or preys on.
According to data published by the Guardian by the Norwegian Institute for Air Research and published in the Guardian, the average tire loses eight lbs of rubber each year.
According to Ocean Blue Project, tires can contribute up to 10 percent to microplastics in oceans.