Wildlife

Fish prefer to eat plastic over food – and it is killing them

Microplastic particles appear to be killing fish because their larvae prefer to eat them rather than their actual food, researchers have warned.

With fears that the amount of plastic in the oceans could soon equal the weight of fish in the sea, scientists have become increasingly concerned about the effects on the marine environment.

Now a study published in the journal Science has found that baby perch will actively choose to eat plastic over the plankton they would normally feed on. The researchers said this greatly increased mortality rates of the perch, stunting their growth and appearing to change usually innate behaviour. For example, they seemed to lose the ability to smell a predator that made them much more vulnerable.

When placed in a tank with a pike, perch exposed to microplastic were eaten four times more quickly than perch that had not been eating plastic. All the plastic-fed fish had been killed within 48 hours.

Microplastic is produced as larger pieces of plastic waste are broken down in the environment, but vast amounts of microfibers from synthetic clothes – things such as fleeces are essentially made of plastic – are produced each time they are washed and are small enough to pass through sewerage treatment plants and get into the sea. Cosmetics companies are also continuing to put plastic microbeads into their products.