Are fish really eating all the plastic?

Scientists are concerned that hundreds of thousands of tons of plastic waste floating in the ocean is being eaten by fish.

An international team of experts has found evidence there is 100 times less plastic on ocean surfaces than expected.

Professor Carlos Duarte, an oceanographer from the University of Western Australia, was part of the study that towed a mesh net through the world’s oceans.

He told the ABC’s Pacific Beat there are a number of possibilities for where the missing plastic has gone but one stands out.

“The disturbing reality is that we cannot account for where the 99 per cent that is missing may be,” he said. “The plastic particles that are missing might be ingested by fish. That one possibility is the most likely one.”

The scientists found about 40,000 tonnes of plastic waste floating in the ocean.

The figure is far less than the one million tonnes that had been predicted based on data going back to 1970.

Professor Duarte says among the concerns with fish eating the waste is the possibility that the plastic could eventually end up in the human food chain.

“These fish eating the plastic are predated upon by tuna, by sword fish and also by squid, all of which end up on our dining plates,” he said.

“So the plastic might actually be coming into the tropic food web of the ocean of which we humans are part.”

Duarte says there is also the chance the plastic is breaking down into pieces too small to detect or that microbes are degrading the plastic.