Not So Healthy: Young Fish Eat Microplastics Like Fast Food

New research shows that young fish are eating tiny pieces of plastic instead of their regular food — with potentially devastating consequences.

A study published this month in the journal “Science” explains that juvenile perch larvae appear to be eating microplastics in place of their usual food sources, like free-swimming zooplankton. This hinders fish development, leaving them more susceptible to predators.

Microplastics — plastic particles that measure below 5mm — infiltrate our environments as a result of litter, such as plastic bags, packaging and other materials, that eventually end up in the sea. Microbeads — tiny plastics often found in health products, such as face scrubs and even some toothpastes — represent another major source of pollution. For this reason, a number of governments have either banned or are considering banning microbeads.

Researchers from Uppsala University in Sweden wanted to look at exactly how plastics might affect immature fish. They began by examined the impact of various polystyrene concentrations on perch.

In non-exposed waters, the perch eggs hatched at a rate of about 96 percent. This dropped to just 81 percent if large quantities of polystyrene were present. The perch that did hatch in these waters tended to be slower and smaller than those observed in cleaner bodies of water.

Furthermore, the researchers observed that juvenile perch in high-plastic environments were more likely to ignore the chemical signals that alert them to the presence of predators — in this case, pike. While half of the young perch in clean waters survived predator interaction over a period of 24 hours, in waters with a high concentration of plastics, all of the perch were consumed.

In total, perch in the high plastic environments were four times more likely to be eaten than those in the clean water. While researchers weren’t able to measure the potential impacts on predator fish, there is some evidence of wider food chain effects.

Perhaps most interesting was the way in which high plastic environments appeared to modify the behavior of the juvenile fish.

Researcher Dr Oona Lonnstedt told BBC News:  ”They all had access to zooplankton and yet they decided to just eat plastic in that treatment. It seems to be a chemical or physical cue that the plastic has, that triggers a feeding response in fish.”

This has led many to compare the perch to teenagers eating fast food. Research has shown that these foods appeal to areas of the brain that encourage young people to eat more of the same foods. It’s unclear if that’s what’s going on here, but something appears to alter how the fish think about food and what appeals to them.

“This is the first time an animal has been found to preferentially feed on plastic particles, and is cause for concern,” Peter Eklöv, co-author of the study, stated. “Larvae exposed to microplastic particles during development also displayed changed behaviours and were much less active than fish that had been reared in water that contained no microplastic particles.”

The researchers say that their study should add further support for widespread bans on microplastics.

Previously, research has identified microplastics as the reason behind apparent digestive problems in fish. However, this new research is among the first to confirm a suspected impact on behavior, too.

It’s not clear how the plastics interfere with how fish respond to threats, though some scientists suggest they may simply damage brain development in the area that carries out risk assessment and feeding behavior. Further research will be needed to more fully understand this problem.

In the meantime, environmental advocates warn that this research demonstrates the ongoing impact of plastic pollution in our oceans. If we really care about issues like plummeting fish stocks, preventing more microplastics from infiltrating our seas is imperative.

Photo credit: Thinkstock.


Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

william Miller
william Miller2 years ago


Melania Padilla
Melania P2 years ago

Nice going humans, good luck future (now) generations!

Victoria C.
Victoria C3 years ago

Patricia Harris, just ignore those people!! They're just upset, as we all should be!!

Jeanne Rogers
Jeanne Rogers3 years ago

Directly or indirectly, humans are responsible for killing everything on the planet.

Patricia Harris
John Taylor3 years ago

Mark Donner wrote '' Humans are on a suicide mission, and they're succeeding admirably in that mission.'' Maxine Stopfer wrote ''Seems like everyday we are hearing of more and more problems in the world with our surviving animals and fish. Soon there will be none left except in story books.'' WRONG!!!!!!!! We are NOT about to let that happen... NOT while we're here to stop it!!

Liliana Garcia
Liliana G3 years ago

"Further research will be needed to more fully understand this problem." I just hope this doesn't n mean exposing a number of fish to higher concentrations of micro plastics. If it comes from plastic it's toxic to consume and that's a fact very well known now.

heather g.
heather g3 years ago

Common sense in NOT common !

Ruth S.
Ruth C3 years ago

Poor fish

Lisa M.
Lisa M3 years ago

I feel so bad for the poor, innocent fish. Humans suck!