Chapter 1: The Phantom Killer of the Sea

It's getting bright on the horizon as Alex peeks out of the hatch. "Do you want to see dolphins?" On deck, the wind hits a sail against the mast, and in the water, the whistle of four dolphins pierces the morning. The pod of cetaceans dives in front of the sailboat's bow for a few minutes before disappearing behind a trawler returning to port south of Mallorca. Alex bids them farewell with a glance and raises a pair of binoculars to scan the horizon. He's searching for a silent killer.

Marine biologist Alexander Sánchez Jones sails the Mediterranean in search of traces of ghost fishing, drifting nets that become deadly traps for turtles and cetaceans. The victims number in the thousands. In Mediterranean waters alone, nearly 150,000 turtles get entangled each year, according to estimates by the World Wide Fund for Nature (WWF).

Alex travels aboard the Va de Bon Coeur, a sailboat handmade over 40 years by a Geneva carpenter who sold his house to build his dream and now lends it to science. The helm is controlled by another Swiss, Sylvain Liechti, who serves as the boat's captain. With the engine off and the sails unfurled, he steers the sailboat towards the island, hugging the Emile Baudot escarpment. The sea, at this hour, resembles a calm lake, concealing a rocky wall almost 300 kilometers wide that plunges more than 2,000 meters deep. The ocean currents rising along the slope make this place a unique paradise in the Mediterranean for turtles and gray whales, among other species.

Between the Baudot escarpment and the Cabrera National Park, Alex spotted a turtle ensnared in a tangle of raffia last year. "Both of its front flippers were trapped, and we thought it was going to die," he recalls. They named her Amor. If the turtle hadn't died, it was thanks to another key member of the team that defends marine life: biologist Xisca Pujol, responsible for the turtle recovery center at the Palma Aquarium Foundation.

The foundation's epicenter, hidden in the basement of the facility, is a climate-controlled room housing five pools the size of tractor wheels. In all of them, turtles swim leisurely in circles. On the wall of each pool hangs a slate with the name, location, and date each injured animal was found. Clad in a bright blue T-shirt, Xisca knows the stories of nearly 25 turtles they host every summer by heart. "She was here for two months, and we saved one of her front flippers." Half of the specimens return to the sea with one of their flippers amputated. If Amor had lost both flippers, they would have had to euthanize her. In the wild, she wouldn't have survived.

For Xisca, there is no doubt that a phantom killer is lurking in the Mediterranean. Although they have always cared for turtles injured by fishing gear, it wasn't until 2018 that they began treating injuries from entanglement in raffia and plastic bottle tangles. "It's a problem that didn't exist until five years ago."

Xisca's account coincides with that of Ricardo Sagarminaga, founder of Alnitak, the organization of marine biologists to which Alexander Sánchez Jones belongs. They have been sailing in open seas for more than 30 years to study marine life. Since they found the first one five years ago, they have dismantled more than 600 such artifacts.

The remnants of ghost fishing are the latest development in a larger problem that has concerned the Balearic Islands for decades. Before the regulation of drift longline fishing, many turtles were injured by the hooks of this technique. It no longer happens in the islands, but in the western Mediterranean, it continues to wreak havoc.

There, drift longline nets pose a significant threat to the turtle population. Members of Alnitak know this well: on their expeditions in Alboran, they often find turtles trapped in these types of nets. In the western Mediterranean alone, almost 40,000 turtles get entangled in such nets each year.

The sun's marks on Ricardo's skin bear witness to his nearly 40 years of experience in the Mediterranean, first with Greenpeace and later with his own NGO. Sitting on a ledge of the sailboat with a cup of coffee in hand, he looks south to find the root of the problem: "These tangles of painted plastic bottles are the typical survival fishing artifacts used in North Africa."

Armed with fieldwork, Ricardo visited researchers from the Coastal Observation System of the Balearic Islands (SOCIB) to cross-reference them with ocean current models and determine the origin of these ghost fishing specimens. Science supported his findings. The data pointed to four locations in Algeria and Morocco. "We believe it's a very cost-effective fishing technique used by migrants settled on the coast of the African continent."

It's a rudimentary system made from reused plastic bottles and pieces of raffia that are weakly anchored to the seabed with a rope. When they break, the current carries them into the sea. Over time, these artifacts become small ecosystems. They create an oasis effect: first, algae and small fish arrive, attracting medium-sized species like tuna. In five weeks, these objects can gather dozens of kilograms of fish around them. The last to arrive are the largest animals, such as turtles, dolphins, or sharks, which are seduced by this whirlpool of life and become trapped in the nets.

The remnants of survival fishing are the latest development in a larger problem that has concerned the Balearic Islands for decades. Before the regulation of drift longline fishing, many turtles were injured by the hooks of this technique. It no longer happens in the islands, but in the western Mediterranean, it continues to wreak havoc. There, drift longline nets pose a significant threat to the turtle population. Members of Alnitak know this well: on their expeditions in Alboran, they often find turtles trapped in these types of nets. In the western Mediterranean alone, almost 40,000 turtles get entangled in such nets each year.

Finding them is difficult, and finding them in time to save their lives is even more challenging. "Think of this as enormous," says Alex as he extends his arms forward from the bow of Va de Bon Coeur, "it's like looking for a needle in a haystack." On board the sailboat, it's easy to mistake any swell or splash in the distance for a ghost fishing artifact.

The happy ending of the turtle Amor is almost an exception. "We arrived just in time; she was on the brink when we found her," Alex recalls. 

Despite this, he doesn't give up. He picks up the binoculars again, fixes his gaze ahead, and inspects the vast blue expanse. If luck plays a crucial role in finding a turtle, finding dolphins is more complicated. When they get entangled, they sink without a trace. The turtle Amor was lucky, but dolphins like these, he points in the direction they went, do not have the same luck.

This article was produced with support from Internews' Earth Journalism Network. It was first published in La Vanguardia on 26 August 2023 in Spanish.

Banner image: Sunset on the deck of the research sailboat Va de Bon Coeur, Spain, July 2023 / Credit: Laura Aragó.