Tiny plastics cause big problems for perch

Microscopic pieces of plastic rule Earth’s oceans, with numbers in the billions — possibly trillions. These tiny plastic rafts provide homes to microbes, but their ecological effects remain murky.

In a lab at Uppsala University in Sweden, researchers exposed European perch (Perca fluviatilis) larvae to a microplastic called polystyrene to see how they might react. The exposure triggered a slew of potentially negative effects: Fewer eggs hatched, growth rates dropped and feeding habits changed, with some larvae preferring polystyrene to more nutritious food options. Exposed larvae were also sluggish in response to scents that signal approaching predators in the wild, the team reports in the June 3 Science.

European perch serve as a keystone species in the Baltic Sea, and the fish have recently experienced a population dive. Because the drop has been linked to juvenile feeding issues, the researchers argue that microplastics could be to blame.