Home sci-tech Ghost nets: Tackling a silent killer of the seas


Ghost nets: Tackling a silent killer of the seas

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Ghost nets: Tackling a silent killer of the seas

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Giannis Athinaios

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Jannis Athinaios has been fishing off the coast of Greece for over three decades

Jannis Athinaios is preparing to sell her merchandise, a variety of fresh red mullet, red snapper, gold and sea bream, in the sunny harbor of Nea Makri, a coastal town 25 km northeast of Athens.

For 31 years, he has been fishing in the South Euboan Gulf, mostly at night, going to the port of Nea Makri at noon to sell his catch, either at local restaurants or at many loyal customers.

"I use small networks," says Athinaios. "Occasionally I lose some of them, but nothing special – about 10 million a year, which costs me about 20 euros," he says.

But imagine these lost nets enlarged to the size of the giant nets used by ocean trawlers.

"These large boats use nets that are over 45m high and 800m long, which can cost from five to six thousand euros or more," says Athinaios.

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When these nets get lost at sea, they become ghost nets, an expense for fishermen and deadly for marine life.

It is difficult to measure the scale of the problem, but in 2009 Estimated United Nations Food and Agriculture Organization 640,000 tonnes of fishing gear were lost or discarded in the seas throughout the year.

In 2015, a single WWF mission in the Baltic recovered 268 tons of nets, ropes and other materials.

And because the nets are made of nylon or other resilient synthetic compounds, they can survive in the oceans for decades, capturing, injuring and killing all kinds of marine life.

Phantom nets also damage corals, breaking their brittle skeletons, destroying their soft tissues and killing large pieces of the reef.

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Giannis Athinaios

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Rugged modern nets can survive for decades in the ocean

To help solve the problem, British, Portuguese and Spanish organizations and universities, and figures from the European fishing industry, are cooperating on a project called NetTag.

The goal is to promote new technologies that reduce the number of lost nets and educate fishermen about new practices to limit losses.

Its main technology is a special underwater acoustic transponder – the NetTag – that anglers can attach to their nets and other equipment.

NetTag transponders work by using sound waves, which travel efficiently over long distances underwater.

When the surface vessel sends a signal, the transponder responds and by calculating the time difference between the signal and the response, the network can be located.

"At an estimated cost of about 300 euros each, NetTag can help fishermen protect assets costing thousands of euros," says Jeff Neasham, an electrical engineer at the University of Newcastle and lead researcher for the project.

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Newcastle University

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NetTag transponders can be connected to fishing nets

Dr. Neasham helped design the transponders, the size of a matchbox.

They have batteries similar to smartphones, but use circuits that require very low power, meaning they can operate for many months connected to a network.

"These transponders definitely work. The technology is practical," says Brian von Herzen, environmentalist and chief executive officer of Climate Foundation, a nonprofit food safety organization.

However, he is not sure that NetTag is appealing to big fishing boat operators, who may not want to waste time recovering lost nets.

Von Herzen says that even if the new transponder allows boats to locate lost nets, they can still spend half a day recovering the equipment. This time may be more valuable than the price of the network.

Athinaios finds NetTag environmentally very promising, but is also skeptical about modifying the behavior of her fellow professionals.

Since 2009, a Council of the European Community regulation requires fishing vessels to recover all lost fishing gear as soon as possible – carrying equipment on board for that purpose – or potentially facing severe fines and finally confiscating the vessel or fishing gear.

"However, nothing has changed," says Athinaios.

"The law is not enforced. Most of us have equipment like GPS and plotters. Big boats have advanced equipment and scuba teams to track down lost equipment, but they don't because they can earn € 6,000 at the cost of a network. lost on any day ".

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Jeff Neasham

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Jeff Neasham is convinced that transponders can save fishermen time and money.

Dr. Neasham says that if anglers have the precise coordinates to retrieve a network via GPS, they are not really looking for a phantom network.

"We are talking about situations where the equipment was moved by thunderstorms, away from moorings or caught by other vessels and released," says Neasham.

"The captain of our research boat has been involved in many attempts to recover lost equipment, and even when they are confident they know where a phantom network is, the network may be several hundred meters away, where they can finally connect it. . "

He is convinced that NetTag will save a lot of time and money.

Von Herzen thinks the solution is to reward fishermen for recovering ghost nets.

In regions such as Europe, where fisherman catch is limited, he suggests that for each recovered net this limit may be increased.

"In that case, these low-cost transponders would be useful," says von Herzen.

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Giannis Athinaios

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Transponders can encourage fishermen to recover nets

"We should propose these revised regulations and have a public comment period where we would have meetings and discussions in town – rather than lectures – with fishermen," he adds.

He thinks this may also change the fishing culture. "They would consider themselves stewards of the ocean," suggests von Herzen.

In the coming months, the NetTag project will conduct full field trials with fishermen in Portugal and Spain, who will be the first to try the technology before it hits the market.

Dr. Neasham is confident that the effort will end the "epidemic" of phantom networks.

"We should expect 90% of lost fishing gear to be recovered in the developed world within the next 10 years if the project becomes mainstream."

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