IT’S been known for many years that the fish we eat are exposed to toxic chemicals in their natural habitats, however a study by Swedish researchers found that fish can become addicted to eating the plastics in the same way that humans can become hooked on fast food.
In order to investigate the bearing of micro-plastics in the early life stages of fish, researchers exposed perch larvae to different concentrations of polystyrene in water tanks.
84% of eggs exposed to larger quantities of micro-plastics successfully hatched, compared to 96% of those in clean water.
According to lead author Dr OonaLonnstedt, from Uppsala University, the fish hatched in highly contaminated water were “smaller, slower, and more stupid.”
When exposed to predators the fish raised in the strongest plastic concentrations were all consumed within 24 hours, whereas half of the perch raised in clean water survived the same time period.
Further, every tank had access to zooplankton however the perch all “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,” Dr Lonnstedt said.
“They are basically fooled into thinking it’s a high-energy resource that they need to eat a lot of. I think of it as unhealthy fast food for teenagers, and they are just stuffing themselves.”
The researchers have linked the increase of deaths at the juvenile stageto the decline of certain species witnessed in the Baltic Sea over the last two decades. They argue that if plastics are affecting young fish, it could have “profound effects” on ecosystems.
A study last year estimated that about 8 million tonnes of plastic waste enters the oceans yearly, and according the new research published in the journal Science it is estimated in the next decade there will be one kilogram of plastic waste in the ocean for every three kilograms of fish.