Young fish become hooked on eating plastic in the seas in the same way that teenagers prefer unhealthy fast food, Swedish researchers have said.

Their study, reported in Science, found exposure to high concentrations of polystyrene makes perch larvae favour the particles over more natural foods.

As a result of exposure to plastic, the young perch are smaller, slower and more susceptible to predators.

The researchers called for plastic micro-beads to be banned in cosmetics.

Chemical degradation

Concerns have been growing about the amount of plastic in the seas in recent years.

A study that came out last year estimated that about 8 million tonnes of plastic waste enters the oceans annually.

When exposed to UV radiation, chemical degradation and the movement of the waves, this plastic breaks down into tiny pieces. Those smaller than 5mm are referred to as micro-plastics. The term also covers plastic micro-beads from personal care products.

Scientists have been worried that these tiny fragments can build up in the guts of marine creatures and can also leach toxic chemicals.