Fish eat plastic in sea because it smells like food, tests show

THE reason why fish eat plastic when it is dumped in the ocean has been discovered by scientists.

Tests on anchovies show that when plastic is mixed with salt water and begins to disintegrate it releases an odour which is similar to krill.

The enticing smell sets off foraging and feeding behaviour in fish, causing them to eat the debris, believing it is food.

Previously scientists thought that fish were ingesting tiny particles of plastic by accident when they were hoovering up floating pieces of plankton or krill.

But the new study suggests the problem is even more serious, because fish are actually attracted to the plastic.

Writing in the Proceedings of the Royal Society B, first author Dr Matthew Savoca of the University of California and the US government’s National Oceanic and Atmospheric Administration, said: “These results demonstrate that odours associated with plastic debris stimulate a behavioural response consistent with foraging in captive anchovy schools.

“As when foraging, the anchovy responded to the medium and high concentrations of biofouled plastic odour. Similar results were seen in response to all concentrations of food odour, thus indicating anchovy use odours to initiate foraging behaviours.

“This is the first behavioural evidence that plastic debris may be chemically attractive to marine consumers. These chemical cues may lure consumers, such as anchovy, into regions of high plastic density and activate foraging behaviours.”

“These findings have considerable implications for aquatic food webs and possibly human health.”