Ghost fishing nets 'death traps' for marine life
Wednesday, 6 November 2019
Abandoned fishing gear, the equivalent weight of more than 50,000 double decker buses, is estimated to be choking the world's oceans.
Plastic is increasingly used in ropes, nets and lines, because it is cheap, light and durable.
But once it is lost, or deliberately abandoned at sea, it remains for decades. The litter can be deadly to wildlife, often found in the stomachs of dead sea birds and whales, or ensnaring and disfiguring sharks, turtles and dolphins.
A new report from Greenpeace says an estimated 640,000 tonnes of 'ghost gear' enters the ocean every year.
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It makes up 10 per cent of the plastic waste in the world's oceans, the report says. But in some areas the proportion is higher: 86 per cent of megaplastics found in the Great Pacific Garbage Patch, between Hawaii and California, were fishing nets.
The report also references a Stuff investigation, published this year, that revealed seven plastic fish bins from New Zealand companies had washed up on remote Henderson Island, more than 5000 kilometres across the Pacific Ocean.
Two of the companies had gone out of business in the 1990s.
The crates were found as part of a clean-up expedition which gathered six tonnes of debris on a 2.5km stretch of beach.
About 60 per cent of the trash was plastic originated from industrial fishing. Fishing buoys totalled around 40 per cent of the weight, and rope and nets made up 20 per cent.
Around a dozen fish aggregation devices (FADs), rudimentary rafts with netting that drifts as deep as 100 metres below the surface, were found washed up on the island's East Beach.
Fishermen deploy FADs at sea because valuable catch, like tuna, shoal beneath them. They also boost the efficiency of purse seine vessels, which use enormous nets to encircle skipjack tuna.
The Greenpeace report says there has been a rise in the number of intentionally abandoned FADs, which are tracked by GPS-equipped buoys, in the Eastern Tropical Pacific, which extends from Mexico to northern Peru.
It also quotes a 2019 study which found six per cent of all nets are lost annually. The 'main villains' are vast gillnets which target slow-maturing deepwater fish.
Greenpeace New Zealand oceans campaigner Jessica Desmond wants the Government to include fishing gear in the Waste Minimisation Act , which regulates dumping, so commercial companies are held to account.
'It is not a case of saying no fishing or no plastics. It is a case of saying be responsible for how we are using it. What we are asking for is product stewardship of the plastics that these companies are using.
'What that could look like is all fishing gear is labelled to those companies, making sure there is a check-in, check-out system at ports so the plastic is that is leaving is actually coming back.'
The ghost gear is also a hazard to shipping navigation and can damage other equipment. It is also costly, difficult and dangerous to remove.
'It is to the benefit of fishing companies as well. If you are killing habitats … [and] marine life, you are killing off your fish.
'It is also a danger when it comes to navigating, if there are enormous nets floating around in the ocean.'
Greenpeace also wants a UN Global Ocean Treaty, which would create more sanctuaries and address marine pollution, in place by 2020.
'Last year we saw a net with 300 dead turtles come up in Mexico … on a global scale we want to make areas off limits to fishing to limit the amount of dumping.
'We have a chance to do that. There is an oceans treaty being negotiated right now and if we get it right we could have a network of global ocean sanctuaries and that would make a huge difference for our oceans.'