By: Valérie DEKIMPE
If you think fishing nets are made of natural rope, think again — they're made of plastic. Every year, some 80,000 km² of nets are lost and abandoned at sea. As they drift aimlessly, these so-called "ghost nets" litter the ocean floor and trap nearly everything in their path. We take a closer look in this Edition of Down to Earth.
Robot to the rescue The problem of "ghost nets" is widespread in the south of France, where scientists and divers often come to the rescue in order to remove fishing gear that's been abandoned. French association 'Les Ressources Sous-marines' is one of them. The small company has built a robot that can scour the sea floor in search of nets and retrieve them.
The team receives a call warning them of a possible sighting off the island of Porquerolles. The robot is equipped with a camera and can reach a depth of 300 metres. Once the net has been found, the rover will collect it and bring it to the surface. Divers can also be deployed to assist in the process.
"As people who love the sea, we're obviously not big fans of ghost nets. We'd love to get rid of them," says Olivier Trubert, the association's vice president.
"It breaks our hearts but it's also heartbreaking for fishermen who lose their nets and their livelihoods."
The vicious cycle of abandoned gear Losing gear is almost always accidental. Each net can cost up to €10,000, so it's not in the fisher's interest to leave their gear adrift in the ocean. Nets can get lost due to bad weather, or become entangled with other vessels and accidentally cut off. They can travel for miles along with the current, and that makes them extremely hard to track down. On the whole, lost fishing nets make up for 10 percent of all marine plastic waste.
The scientific community takes the danger posed by ghost nets very seriously. Sandrine Ruitton from the Mediterranean Institute of Oceanography explains how fishing nets wreak havoc underwater.
On the one hand, abandoned nets continue to catch fish, which in turn attract bigger animals like birds that end up getting trapped and die asphyxiated. But it doesn’t end there. Eventually, nets will sink to the bottom of the sea and cover the natural habitat.
"We see that rocks covered by nets are also covered in thick mud. The sediment stays on the rock and it will suffocate marine habitats," says Ruitton. "So much so that it will prevent algae from growing, sponges from developing."
She's also in charge of a project focusing on the resilience of ecosystems once nets have been removed. In just one year, natural habitats are capable of reclaiming their former territory, according to Ruitton. "We were stunned by how quickly nature recolonised the seabed. It shows the effectiveness of removing nets if we want to improve the state of the environment."
Once retrieved, what’s next? Over the last few decades, fishing nets have been getting thinner and more fragile. Many are made of nylon and thus degrade more quickly, generating waste along the way. Currently, old fishing nets don't get recycled. Sabine Meneut wants to change that with the startup she founded, called Glokis. Armed with only a van, every three months she collects nearly 100 kilos of discarded fishing nets set aside by a group of fishermen in Port-de-Bouc, a small port west of Marseille. "Fishing nets lost at sea cannot be recycled," says Meunet. "We can’t transform them."
The reason behind it this fairly simple, she adds. They're dirty, loaded with organic material and smelly: not ideal candidates for recycling. Old fishing nets, on the other hand, do have a shot a second life. But they require a lot of work to sort them out, according to the young entrepreneur: "We have to remove any plastic waste, organic waste, so seagrass, seaweed, sponges. We also find small pieces of rock inside."
Once they've been bundled up in large "sausages", they get sent to another company in Brittany where the recycling process can begin. Nets are transformed into recycled plastic beads, sunglasses or surfboard fins.
A biodegradable solution? At 3am in the port of Fecamp, Normandy, it's time for Kevin Truchon and two other fishermen to head out to sea on board the Gauthier-Lucile for yet another long day of work. They'll spend not less than 14 hours fishing sole and squid. But they have another important mission to tend to: testing biodegradable nets.
These are made of plastic and a biopolymer derived from corn or sugar cane. In theory, they degrade more quickly once they're in the water and without disseminating any nasty microplastic. The hope is that they could limit the damage caused by fishing nets when they get lost at sea. Truchon joined the pilot programme five months ago. "I think it’s great," he says. "It helps to avoid ghost nets, to avoid pollution and pointless overfishing."
There's still room for improvement when it comes to the net's technical properties, he adds: "It's the same type of mesh except this one is thicker. That's why right now the nets are a bit stiff. If they were more flexible, they would be better."
But there's something else that is putting him off: the price. With oil prices going up, it's become a lot harder to invest in new, more expensive fishing nets, even though he hasn't given up on the idea altogether.
"If we use biodegradable nets, we'll have a clear conscience," he concludes. "The less we pollute, the better it will be for us in the future."
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