This article was created in partnership with the National Geographic Society.

A pregnant sperm whale washed up, dead, on a sandy beach outside Porto Cervo, a resort town on Italy’s island of Sardinia last week. When scientists and veterinarians cut open her womb and stomach, they found a horrifying sight: A dead baby whale, and nearly 50 pounds of plastic waste jammed into her belly.

The plastic filled more than two thirds of her stomach. They could also see the remains of some of the squid she'd eaten—but the nutrients from that food likely never made it into her bloodstream, because her intestines were blocked by the morass of plastic waste.

“I never saw such big quantity of plastic,” said Luca Bittau, a marine biologist at SEAME Sardinia, a nonprofit organization that focuses on studying and protecting the cetaceans that live in the region. They found fishing nets; fishing lines; plastic bags, some so fresh the barcodes were still readable; plastic pipes, and even some plastic plates “like those that we have in our home,” he says. “It was like our usual life was there, but inside this stomach.” The realization, he said, was devastating.

Crystal waters above, plastic wasteland below

The scientists think the 26-foot long whale was part of a pod that spends its time feeding and birthing its babies in the nearby Caprera Canyon, a crevasse deep below the crystalline surface waters of the Mediterranean Sea. The region is popular with tourists and boaters, and biologists thought the biggest challenge the whales faced were the dangers of boat strikes—not plastic pollution.

But under the beautiful surface of the sea, says Bittau, the situation is ugly. Plastic litters the deep ocean floor, where the sperm whales and their closely related brethren go to eat. They dive deep into the canyon, using echolocation to search for the squid they like to eat.

But a plastic bag waving in the deep ocean currents could be difficult to distinguish from a fluttering squid. And once a whale ingests it, that bag is stuck there. Each mistake a feeding whale makes adds to the problem, and slowly its stomach fills with the deadly material.

This whale’s cause of death has not yet been determined. Veterinarians and scientists at the nearby University of Sassari are still investigating what, exactly, killed it and the baby. But this whale is only the most recent in a long list of marine mammals that have been found dead with plastic packed into their stomachs.

A global problem

“Plastics are now found everywhere in the world, throughout the entire marine ecosystem and food chain, from seabirds to sea turtles to seals,” says Nick Mallos, the director of the Trash Free Seas program at the Ocean Conservancy, a nonprofit that focuses on ocean protection. “It’s a truly global problem with inputs that are at a massive scale, and we’re seeing the impacts grow and grow.”

Plastic pollution has penetrated to the deepest crevasses of the ocean, and the Mediterranean is no exception. It collects waste from the countries bordering it, and because the ocean is a closed basin, that waste stays trapped in its waters—essentially forever. In a recent report, Greenpeace estimated that most of the 150,000 and 500,000 tons of large plastic debris that enters European waterways ends up in the Mediterranean each year.

In response to the plastics crisis, the European Union recently passed a ban, scheduled to go into effect in 2021, on many types of single-use plastics.

But that’s not soon enough to save this whale.

“This is another tragic example of the real impacts that plastics have when they enter the ocean,” says Mallos. There are many challenges facing the world’s oceans, he says, “but plastic pollution is the one we know the solution to. We don't have to worry about changing ocean chemistry or about managing fish population stocks. We just have to turn off the tap of plastics flowing into our waters.”

“We all felt responsible when we saw those things inside the whale,” says Bittau—from the plates, like he and his colleagues used in their own homes, to the bags, to the pipes. So it’s up to all of us, he says, to fix it.