MANOA, Hawaii (KFOR/Storyful) – Researchers believe they know what killed a 56-foot sperm whale that washed ashore on the Hawaiian island of Kauai, after examining the contents of its stomach.

Video at the top of this story shows sharply pointed fish traps, seven different types of fishing nets, two types of plastic bags, fishing line, a light protector, and a float from a net.

Marine researchers at the University of Hawaii at Manoa spent 15 hours sorting through the contents, which also included squid beaks and fish skeletons that the whale was unable to digest, most likely due to a blockage.

“The UH researchers found what appears to be monofilament fishing line, with three flies tied to it, which suggests all of the pollutants the whale swallowed did not originate in the ocean but came from land as well,” the Hawaii Department of Land and Natural Resources posted on Facebook. “Massive, male sperm whales transit the ocean over thousands of miles, so there’s no way to tell where the materials originated.”

During their initial exam of the 60-ton whale, researchers also collected several samples from different organs for follow-up testing, though they saw no visible irregularities. They will also screen the samples to determine whether any disease was present.

“We are only able to examine a small number of our dolphins and whales that die in our waters, and we think that each individual we are able to examine represents as many of 20 other animals, who are likely to ultimately die from these types of impacts. It’s heartbreaking to see this kind of destruction in an individual animal,” said Dr. Kristi West, Director of the Health and Stranding Lab at the University of Hawaii at Manoa.