A new Uppsala University study has revealed the dangers of microplastic particles to the development of larval fish, including stunted growth and behavioral changes. In addition, the team showed that larval perch with access to microplastic particles will selectively eat these particles and ignore natural food sources of free-swimming zooplankton.
Microplastic particles are defined as plastic particles less than five millimeters in size. They typically stem from large plastic waste products and make their way into oceans through waterways and lakes. Over time, they reach high concentrations in shallow coastal areas.
Although scientists have been concerned about the increase in microplastic particles and their affects on marine ecosystems, the new study is the first to shed light on the specific damages that fish face from their presence.
"Fish reared in different concentrations of microplastic particles have reduced hatching rates and display abnormal behaviors," said Oona Lönnstedt of Uppsala University and lead author of the study. "The microplastic particle levels tested in the current study are similar to what is found in many coastal habitats in Sweden and elsewhere in the world today."
In addition, larval perch exposed to microplastic concentrations similar to those in today's marine environments showed stunted growth rates, which was connected to larval feeding preferences - those with access to microplastic particles only ate plastic and ignored their natural zooplankton food source.
"This is the first time an animal has been found to preferentially feed on plastic particles and is cause for concern," said Peter Eklöv, also of Uppsala University and co-author of the study.
"Larvae exposed to microplastic particles during development also displayed changed behaviors and were much less active than fish that had been reared in water that contained no microplastic particles," Lönnstedt said. "Furthermore, fish exposed to microplastic particles ignored the smell of predators which usually evoke innate antipredator behaviors in naïve fish."
Due to this lack of predator response, fish that had been consuming microplastic particles were caught and eaten over four times quicker than control fish that were not consuming microplastic particles.
The concerning findings highlight the dangerous effects of microplastic particles and their effects on marine ecosystems, suggesting a need for better management strategies and alternative biodegradable products.
The findings were published in the June 3 issue of the journal Science.
