Whales eat a massive amount of microplastic every day, study finds

A study led by Stanford University researchers has found that blue whales can eat up to 10 million pieces of microplastic daily.

The study, published in Nature Communications, focused on blue, fin and humpback whales, and found earth's largest mammals are ingesting plastic through the prey they eat.

Microplastics are tiny plastic fragments produced from the breakdown of larger pieces including bottles, packaged food wrappers and plastic bags. A piece of microplastic is about the same size as a grain of sand.

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The majority of plastic items take hundreds of years to break down. A plastic water bottle, for example, can take 450 years to decompose.

Stanford researchers studied the whales off the coast of California between 2010 and 2019. The creatures would feed mostly between 50 to 250 metres below the surface, which the study says, "coincides with the highest concentrations of microplastic in the open ocean."

The largest whale species, the blue whale, ingests the most plastic the report says, with an estimated 10 million pieces per day. Researchers believe because of the food source of this species of whale, it increases the amount of microplastic the creature consumes.

"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, co-author of the study and a postdoctoral scholar at Stanford’s marine laboratory on the central coast of California, said in a news release. "There’s only one link: The krill eat the plastic, and then the whale eats the krill."

Humpback whales, which consume fish such as herring and anchovies, ingest an estimated 200,000 pieces of microplastic daily. Researchers determined whales eating mostly krill consume at least 1 million pieces per day.

Fin whales eat both small fish and krill and ingest an estimated three to 10 million pieces of plastic daily.

"Consumption rates are likely even higher for whales foraging in more polluted regions, such as the Mediterranean Sea," Savoca said.

According to the study, researchers believe nearly all microplastic comes directly from prey the whales are eating, not from the large amounts of seawater consumed while hunting. This discovery has led Shirel Kahane-Rapport, the lead researcher of the study, to worry about the amount of nutrients whales are consuming.

"If patches are dense with prey but not nutritious, that is a waste of their time, because they’ve eaten something that is essentially garbage. It’s like training for a marathon and eating only jelly beans," Kahane-Rapport said.

The effects of microplastics on whales are still largely unknown as researchers race to uncover what this could mean for their health. The study by Stanford is what researchers say is the "first step" to a years-long study of microplastics in the ocean ecosystem.

NOT JUST WHALES CONSUME MICROPLASTICS

Previous studies have also found plastic fragments inside human blood and stool.

A study by Environment International reports some microplastics were found in almost 80 per cent of the sample of people tests. It also determined microplastics can move around the body and may remain in certain organs.

Previous research has linked microplastics in humans from food and water as well as breathing in pollution.

Last summer, University of Toronto researchers found that Lake Ontario was overflowing with microplastics. Researchers collected bins of plastic from the lake in the summer of 2021 and found each bucket had about 1,600 pieces of microplastic after one 24-hour period.