Twelve million tonnes of it

end up in the ocean every year.

Each year, it's likely over half a million

animals are ensnared and killed by these ghost nets.

But some animals are learning

how to take advantage of the plastic rafts,

and use them for shelter or even as a home.

This male Columbus crab,

barely bigger than your thumbnail,

is a castaway.

Clinging to his net,

he may have been drifting on ocean currents for months.

Now fully grown, he needs to find a partner.

Columbus crabs are not good swimmers,

so this male is marooned.

Perhaps a passing loggerhead turtle

could be the chance to hitch a lift.

Made it.

But there is more than one passenger here.

A female Columbus crab.

They waste no time in getting acquainted

and start to mate.

This pair may well stay together

for the rest of their lives.

A turtle, after all,

makes an excellent home.

In return, the crabs provide an onboard grooming service.