Pictured: 56-foot whale dies after eating huge amounts of plastic

A sperm whale that washed up in Hawaii was found to have seven types of fishing nets, plastic bags, a light protector, fishing line and a float in its stomach.

Scientists said the whale probably died because it ate large volumes of marine debris, highlighting the threat to wildlife from the millions of tons of plastic that ends up in oceans every year.

The body of the 56-foot-long, 120,000-pound animal was first noticed on a reef off Kauai on Friday. High tide brought it ashore on Saturday.

Kristi West, the director of the University of Hawaii's Health and Stranding Lab, said there were enough foreign objects in the opening of the whale's intestinal tract to block food.

"The presence of undigested fish and squid lends further evidence of a blockage," she said in a news release from the Hawaii Department of Land and Natural Resources.

The whale's stomach contained six hagfish traps, seven types of fishing net, two types of plastic bags, a light protector, fishing line and a float from a net. Researchers also found squid beaks, fish skeletons and the remains of other prey in the whale's stomach.

It's the first known case of a sperm whale in Hawaii waters ingesting discarded fishing gear, Ms West said.

The whale's stomach was so large Ms West's team wasn't able to examine it completely. They suspect there was more material they weren't able to recover.

Researchers found nothing wrong with other organs they examined. They collected samples to screen for disease and conduct other follow-up tests.

Sperm whales travel across thousands of miles in the ocean so it's not clear where the debris came from.

Scientists say that more than 35 million tons (31.9 million metric tons) of plastic pollution is produced around Earth each year and about a quarter of that ends up around the water.

Seabirds can ingest as much as 8 per cent of their body weight in plastic. Endangered Hawaiian monk seals and green sea turtles can get caught in plastic nets and die.

Sharks and other apex predators eat smaller fish that feed on microplastic, which can then endanger their own health.

In addition to eating plastics, large whales are harmed when they become entangled in fishing gear or other ropes in the ocean. The drag from debris can force whales to use more energy to swim and make it harder for them to eat, causing starvation.

Sperm whales are an endangered species found in deep oceans across the world. A 2021 report from the National Oceanic and Atmospheric Administration estimated there were about 4,500 sperm whales in the waters around the Hawaiian Islands, from the Big Island in the south to Kure Atoll in the north.