ATHENS, GREECE - JUNE 26: Plastic cups used by tourists on the Aegean sea beach near Athens on June 26, 2018 , Greece . The Mediterranean is one of the seas with the highest levels of plastic pollution in the world .More than 200 million tourists visit the Mediterranean each year causing the 40% increase in marine litter during summer  using  single use plastics including straws and stirrers, plastic cups, water bottles , inflatable pool toys etc which   leads to the general pollution of water and beaches along Mediterranean. (Photo by Milos Bicanski/Getty Images)
ATHENS, GREECE - JUNE 26: Plastic cups used by tourists on the Aegean sea beach near Athens on June 26, 2018 , Greece . The Mediterranean is one of the seas with the highest levels of plastic pollution in the world .More than 200 million tourists visit the Mediterranean each year causing the 40% increase in marine litter during summer using single use plastics including straws and stirrers, plastic cups, water bottles , inflatable pool toys etc which leads to the general pollution of water and beaches along Mediterranean. (Photo by Milos Bicanski/Getty Images)
PHOTO: Milos Bicanski/Getty Images
Now playing
01:22
Plastic pollution is killing these animals
Now playing
02:38
Biden: Science team 'among the brightest, most dedicated'
Mike Pence remarks vpx
Mike Pence remarks vpx
PHOTO: Senate TV
Now playing
02:27
New timeline shows just how close rioters got to Pence and his family
MyPillow notes
MyPillow notes
PHOTO: Jabin Botsford
Now playing
02:21
Photographer snaps notes of MyPillow CEO after visiting Trump
PHOTO: CNN
Now playing
02:31
Teachers feel pressure as schools weigh in-person classes
Staffer White House move out
Staffer White House move out
PHOTO: CNN
Now playing
01:36
Moving trucks spotted at White House as staffers clean out their desks
southern california january strong winds low humidity fire conditions weather santa ana winds_00000000.png
southern california january strong winds low humidity fire conditions weather santa ana winds_00000000.png
Now playing
01:19
Fire weather prevalent across Southern California
PHOTO: CNN
Now playing
02:34
Blizzard, rain, and snow to hinder Central and Eastern US weekend weather
PHOTO: POOL
Now playing
00:48
Pence makes surprise visit to Capitol to thank National Guard
FBI Director Christopher Wray speaks during a virtual news conference at the Department of Justice on October 28, 2020 in Washington, DC.
FBI Director Christopher Wray speaks during a virtual news conference at the Department of Justice on October 28, 2020 in Washington, DC.
PHOTO: Sarah Silbiger/Getty Images
Now playing
03:47
FBI director speaks publicly for first time since Capitol riots
PHOTO: From Public Report / Jeremy Lee Quinn
Now playing
01:39
Video from inside Capitol raises questions for investigators
A man receives a dose of the Moderna coronavirus disease (COVID-19) vaccine at a vaccination site at South Bronx Educational Campus, in the Bronx New York on January 10, 2021. (Photo by Kena Betancur / AFP) (Photo by KENA BETANCUR/AFP via Getty Images)
A man receives a dose of the Moderna coronavirus disease (COVID-19) vaccine at a vaccination site at South Bronx Educational Campus, in the Bronx New York on January 10, 2021. (Photo by Kena Betancur / AFP) (Photo by KENA BETANCUR/AFP via Getty Images)
PHOTO: KENA BETANCUR/AFP/Getty Images
Now playing
02:25
Coronavirus cases surge as states struggle to vaccinate
Now playing
00:00
See inside the first UK hotel converted into a Covid-19 ward
House impeachment 217
House impeachment 217
PHOTO: CNN
Now playing
02:08
See historic moment House reaches enough votes to impeach Trump
PHOTO: Pool
Now playing
01:25
Pelosi speaks for first time following Trump's historic 2nd impeachment
(CNN) —  

More than half a million hermit crabs have been killed after becoming trapped by plastic pollution on two remote islands, a new study from the University of Tasmania found.

Hermit crabs with Cocos Island plastic debris.
Hermit crabs with Cocos Island plastic debris.
PHOTO: Silke Stuckenbrock

Research teams estimated that about 508,000 of the crustaceans have been killed in the Cocos (Keeling) Islands in the Indian Ocean and about 61,000 on Henderson Island in the Pacific after getting stuck in debris such as plastic bottles, which researchers said served as “deadly traps.”

Hermit crabs do not have shells of their own, and instead use empty shells or hollow objects to shelter and protect their bodies.

Dr Lavers found more than 500,000 Cocos Island hermit crabs in discarded plastic buckets.
Dr Lavers found more than 500,000 Cocos Island hermit crabs in discarded plastic buckets.
PHOTO: Silke Stuckenbrock

“When we were surveying debris on the islands, I was struck by how many open plastic containers contained hermit crabs, both dead and alive,” Dr Jennifer Lavers, who led the study, said in a statement.

The study, led by the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania, found that discarded plastic created a “physical barrier” for wildlife attempting to navigate their surroundings and acted as a trap for the crabs.

The research team carried out surveys across a range of sites on the islands to establish how many containers had potential to trap the crabs, and found that around 1-2 crabs per square meter had been trapped by the debris.

’Gruesome chain reaction’

Dr Alex Bond, from London’s Natural History Museum, which assisted with the study, described the problem as “insidious.”

He said: “Hermit crabs do not have a shell of their own, which means that when one of their compatriots die, they emit a chemical signal that basically says ‘there’s a shell available’ attracting more crabs who fall into the containers and die, who then send out more signals that say there are more shells available.”

“Essentially it is this gruesome chain reaction,” he added.

In the study, published in the Journal of Hazardous Materials, researchers warned that marine plastic pollution is a global issue, and that comparable losses of the crabs on a global scale would impact on ecosystems.

“Hermit crabs play a crucial role in the health of tropical environments by aerating and fertilising soil, and dispersing seeds and removing detritus, as well being a key part of the marine ecosystem,” Lavers warned. “Their population degradation is more than just a risk to the natural environment,” she added.

“High concentrations of debris are now being encountered on beaches around the world, many of which are also home to hermit crabs that can be expected to interact with plastic pollution in the same way as those we studied,” Lavers added.

In May, researchers revealed that 414 million pieces of plastic were found washed ashore on the Cocos (Keeling) Islands.

Much of the rubbish was single-use consumer items such as bottle caps, straws, shoes and sandals, eco-toxicologists from the University of Tasmania said at the time.