Blue whales, the largest creatures on Earth, are ingesting 10 million pieces of microplastic daily, scientists estimate.
With plastic waste rapidly accumulating in the world’s oceans, researchers sought to gauge how much is consumed by humpback, fin, and blue whales off the U.S. Pacific Coast. All three feed by gulping up mouthfuls of krill and other tiny creatures and then pushing the seawater out through a bristle-like filter called a baleen. In the process, they are prone to swallowing large amounts of plastic.
Scientists estimated the weight of plastic ingested by tracking the foraging behavior of 65 humpback whales, 29 fin whales, and 126 blue whales that were each tagged with a camera, microphone, and GPS device that had been suction-cupped to their back.
Accounting for the concentration of microplastics off the Pacific Coast, scientists estimate that humpbacks whales who favor krill over fish likely consume around 4 million microplastic pieces each day, or up to 38 pounds of plastic waste. Fin whales swallow an estimated 6 million pieces each, amounting to as much as 57 pounds of plastic. And blue whales eat an estimated 10 million microplastic pieces, or up to 95 pounds of plastic waste. The findings were published in the journal Nature Communications.
“They’re lower on the food chain than you might expect by their massive size, which puts them closer to where the plastic is in the water,” Matthew Savoca, a marine biologist at Stanford University and a coauthor of the study, said in a statement. “There’s only one link: The krill eat the plastic, and then the whale eats the krill.” While other marine creatures are at risk of consuming microplastics, Savoca said, “The unique concern for whales is that they can consume so much.”