For years, scientists feared the effects of microplastic pollution but remained uncertain about its consequences on the marine ecosystems. Now, a study from the researchers at Uppsala University in Sweden shows that microplastic pollution causes behavioral changes and stunted growth in young fish.

The study published on June 3 in the journal Science finds that those baby perch with access to microplastic only eat microplastic particles, plastic fragments less than five millimeters in size, and ignored free-swimming zooplankton, their natural food source. Consequently, these fish became less active, suffered stunted growth and ignored the smell of predators compared to the other fish not exposed to microplastic.

The fish without the antipredator behavior were caught and consumed over four times more quickly than other fish. Moreover, the larval perch that ate microplastic particles will most likely be dead within 48 hours.

microplastic pollution

Juvenile pike will select perch larvae that have ingested microplastic particles. Credit: Oona Lönnstedt

Apparently, these microplastic particles travel through waterways or through lakes and then build up in coastal areas, eventually reaching the ocean. Aside from the aforementioned consequences, if more young fish will die, the total fish population will be affected as well as those who depend on it.

“If early life-history stages of other species are similarly affected by microplastics, and this translates to increased mortality rates, the effects on aquatic ecosystems could be profound,” says the study’s lead author Oona Lönnstedt, a marine biologist at Uppsala University.

The research team calls upon new techniques to manage the release of microplastic waste products in the ocean. The results can guide efforts toward determining which materials are most harmful to what species and ecosystem, thereby preventing unnecessary recovery and restoration costs.

However, the discoveries on young perch are only the tip of the iceberg. More intensive investigations are still needed to verify other negative consequences of microplastic pollution on marine ecosystems around the world.