A dead whale that washed ashore in eastern Indonesia had a lump of trash in its stomach including 115 plastic drinking cups and two flip-flops.

Wakatobi National Park chief Heri Santoso said rescuers found the rotting carcass of the 31-foot sperm whale on Monday near Kapota waters in the Southeast Sulawesi province.

Mr Santoso said the mammal was male and the 13 pounds of trash in its stomach were identified as 115 plastic cups, four plastic bottles, 25 plastic bags, two flip-flops, a nylon sack and more than 1,000 other plastic pieces.

The cause of the death was still unknown and the carcass was to be buried on Tuesday without a necropsy because of its decayed condition.

Dwi Suprapti, a marine species conservation coordinator at WWF Indonesia, said: “Although we have not been able to deduce the cause of death, the facts that we see are truly awful.”

Indonesia, an archipelago of 260 million people, is the world’s second-largest plastic polluter after China, according to a study published in the journal Science in January.

It produces 3.2 million tons of mismanaged plastic waste a year, of which 1.29 million tons ends up in the ocean, the study said.

Luhut Binsar Pandjaitan, Indonesia’s coordinating minister of maritime affairs, said the whale’s discovery should raise public awareness about the need to reduce plastic use, and had spurred the government to take tougher measures to protect the ocean.

“I’m so sad to hear this,” said Mr Pandjaitan, who recently has campaigned for less use of plastic.

“It is possible that many other marine animals are also contaminated with plastic waste and this is very dangerous for our lives.”

He said the government is making efforts to reduce the use of plastic, including urging shops not to provide plastic bags for customers and teaching about the problem in schools nationwide to meet a government target of reducing plastic use by 70% by 2025.

“This big ambition can be achieved if people learn to understand that plastic waste is a common enemy,” he told AP.