More than half a million resident crabs have died from being trapped in plastic waste in two remote island groups,media reported, raising concerns. A pioneering study has reportedly found that 508,000 crabs have died in the Cocos Islands in the Indian Ocean and 61,000 in Henderson Island in the South Pacific. According to previous studies, both places have high levels of plastic pollution.
Researchers at the Institute of Marine and Antarctic Research at the University of Tasmania in Australia, the Natural History Museum in London and the community science group Two Hands project found that one or two crabs died from plastic waste on a beach per square metre.
They reportedly surveyed four sites on Cocos and Henderson, looking for plastic containers that would trap crabs and calculating the number of crabs trapped in each container. They then extrapolated the results to 15 other islands in the Cocos Islands.
Because resident crabs often use the smell of recently deceased crabs to find new shells, multiple crabs are trapped in the same spot. At one point, the researchers found that 526 crabs were trapped in the same plastic container.
Bond, senior curator at the Natural History Museum and one of the report’s researchers, said: “The problem is really serious because it only takes one crab. “The resident crabs don’t have their own shells, which means that when one of their species dies, it sends a chemical signal that there’s a shell here, attracting more crabs… In essence, it’s a terrible chain reaction. “
Inhabited crabs are an important part of the tropical environment because they can spread seeds, ventilate and fertilize the soil, so their decline can have a significant impact on the surrounding ecosystem.
Bond says the extent of the damage plastic does to land is underestimated: “In the ocean, plastic is entangled and swallowed by wild animals; on land it’s like a trap, like we see, but it can also be a physical barrier that prevents species from moving on the ground.” “
“These results are shocking, but perhaps not surprising, because the vegetation on and around the beach is a frequent haunt of all kinds of wildlife,” said Levers, the researcher who led the study. “These organisms will inevitably interact with and be affected by plastic pollution, although our study is one of the first to provide quantitative data on such impacts. “
The team reportedly said their findings suggested the need for an urgent survey of the mortality rate of the global resident crabs.