New research published in Nature has found that the Great Pacific Garbage patch (GBGP) currently spinning between Hawaii and California is “increasing exponentially” and is packed with tiny microplastics. Alarmingly, experts say by 2050 there will be more waste in the sea than fish. Using data from multi vessel and aerial surveys, the researchers found this patch of bottles, ropes, toilet seats, fragments, is twice the size of France; vastly greater than other estimates (16 times as much as a previous study from 2014). And – of great significance in a week where we learned that commercial and recreational fishing is going to be allowed into a great swathe of previously protected Australian marine parks - the researchers also found that almost half of the rubbish – 46 per cent - is discarded fishing nets. If we look just at the 42, 000 tonnes of the largest plastics, “86 per cent of their contribution was carried by fishing nets.”

Discarded nets off fishing trawlers are adding to the pollution problem. Credit:Andrew Quilty The authors found that, in the past decade, “while the introduction of synthetic fibres in fishing and aquaculture gear represented an important technological advance specifically for its persistence in the marine environment, accidental and deliberate gear losses became a major source of ocean plastic pollution. Lost or discarded fishing nets, known as ghostnets, are of particular concern as they yield direct negative impacts on the economy and marine habitats worldwide." Material left or lost by fishers is designed to survive in the oceans: strong, thick nets, floats, traps, ropes. And no one has yet studied how much fishing gear is lost at sea, and how much plastic this involves. Should this not be a crucial part of any conversation about fishing in marine parks? Formerly, 50 per cent of the Coral Sea was given the highest level of “green zone” protection, in which mining and fishing is banned. The Turnbull government’s new plan will reduce this to 24 per cent – although mining there is still, we are told, to be banned in that particular area. Hook and Hardy Reef in the Great Barrier Reef Marine Park, in the Whitsundays.

To put it baldly, currently fishing is allowed in 63 per cent of marine parks; the new plan raises this to 80 per cent. Environmental writer James Woodford, author of The Great Barrier Reef and Great White, spent a year travelling around Australia’s Commonwealth marine parks. The crucial question, he says, is not necessarily where the boundary lines of parks are drawn, but what you do within those lines. In other words, how the how the parks are managed – and it is here, that he says, Australia’s regulation of the sea has grown “looser and looser”. He believes placing large trawlers in a reef, is “incompatible with conservation”. “These are fearsome places that are incredibly fragile with delicate ecosystems ... anything that reduces the protection rather than increases it in face of all scientific evidence that says oceans are in trouble has got to be of huge concern to all of us”. Loading

Marine parks, he says, are some of the world's last oceanic wilderness areas: “If you want to see what the Great Barrier Reef was like you need to go to the Coral Sea to understand that. The most striking thing in these places is the richness of the life ... I got to swim with hundreds and hundreds of sharks all in the same place - just life stacked upon life. Or in the Bremer Basin in south-western Australia, there are killer whales, sharks, sunfish. People ‘ohh’ and ‘ahh’ about one whale, but in marine parks like that, there is it so much life you don’t know where to look.” According to the research published in Nature, the high concentration of plastic in the North Pacific GPGP is coming from plastic sources in Asia as well as “intensified fishing activity in the Pacific Ocean”. In 2009, the Food and Agriculture Organisation of the United Nations, reported that there were an estimated 580,000 tonnes of abandoned fishing nets in the sea, drifting across ocean floors, trapping sea creatures in “ghost fishing”. (Coastal clean up data shows that fishing, aquaculture and shipping account for for 28.1 per cent of the global plastic inputs into oceans, but observations from the sea suggest the actual number is much higher.) Much of this we will never see on the sea surface – as most global plastic demand is for buoyant plastic, almost half of the plastic washing into the ocean will quickly sink to the floor, where they will collect in underwater canyons or be compressed in sediment. Others, will of course, be eaten by marine life.

In calculating their estimates, the scientists in this study have been conservative. Surely our response does not have to be the same. Julia Baird hosts The Drum on ABC TV and is a Fairfax Media columnist.