(CNN) When a young sperm whale washed up on a beach in southern Spain, scientists wanted to know what killed it. They now know: waste -- 64 pounds of it. Most of it plastic, but also ropes, pieces of net and other debris lodged in its stomach.

The discovery has prompted authorities in Murcia, Spain, to launch a campaign to clean up its beaches.

"The presence of plastic in the ocean and oceans is one of the greatest threats to the conservation of wildlife throughout the world, as many animals are trapped in the trash or ingest large quantities of plastics that end up causing their death," Murcia's general director of environment, Consuelo Rosauro said in a statement.

El Valle Wildlife Center found 64 lbs of plastic waste on a young sperm whale.

A sperm whale's diet is usually comprised of giant squid. But the 33-foot long mammal that washed up on the beach of Cabo de Palos on February 27 was unusually thin.

The necropsy results, released last week, listed just some of the items scientists found stuck in its stomach and intestines: plastic bags, pieces of net, a plastic water container.

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