Lost at sea: The hidden cost of ghost gear

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."

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