Big Fish
The luxury tuna industry is killing the Mediterranean.
APRIL 3, 2025
PHOTO: Tuna is hauled aboard the fishing vessel during kill and haul operations. (By Nanni Fontana)
In the Mediterranean, bluefin tuna has fed coastal communities for thousands of years. But today, restaurants in Sicily, Malta, Greece, Spain and Croatia mostly serve second-rate tuna, the yellowfin variety that comes from the Pacific or southern Atlantic. Almost all the bluefin tuna from the Mediterranean Sea ends up on the other side of the world, in Japan, Korea, China, and the United States, where it is has become a staple in the kitchens of luxury eateries.
Every year, some 35,000 tons of prized bluefin tuna are harvested in the Mediterranean. Some of these fish are caught in large nets, called purse seines, and dragged for thousands of miles to giant cages, where they are fattened up like geese for foie gras. For every kilogram of weight that a caged bluefin tuna gains, it consumes approximately 15 kg of small, oily fish (by comparison, in the most efficient salmon farms, the ratio is about 1 kg of feed for 1 kg of fat). Bluefin tuna typically increases its weight by about 70 percent: For example, if a fish enters the cage at 150 kilograms, it leaves at about 255 kilograms. The fattened fish — now weighing, in total, between 45,000 and 50,000 tons— are then shipped across the world.
This farming has consequences on the rest of the ecosystem. Some 134,000 tons of frozen pelagic fish — such as sardines, anchovies, mackerel, sprats and herring — are thawed and tossed into European tuna cages every year. That means a major food resource is being sacrificed to profit the few: Instead of being used to fatten tuna intended for luxury restaurants, these fish could provide 670 million meals (assuming 150 g of edible fish per portion).
The docks and logistics areas, which are managed by the Maltese Federation of Aquaculture Producers, are as tightly guarded as a military zone. Access is impossible, and information is not forthcoming in the village either.
“It's like raising lions for meat,” said Emanuela Fanelli, a biologist at Marche Polytechnic University and an expert in marine ecology. “The farming of bluefin tuna is one of the most sensational examples of social and economic injustice. But it’s easy to hide injustice and play all sorts of dirty tricks under water.”
A biologist in charge of one of the largest tuna farms in the Mediterranean, who spoke to us on the condition of anonymity, told us that “today, the emergency is not about the predator, but the prey. [Pelagic fish] are being plundered in the name of a completely unsustainable business.”
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Malta is a global superpower when it comes to bluefin tuna farming. The island country owns 26 out of the approximately 100 cages that are scattered among Spain, Italy, Croatia and Portugal, despite having the most limited territorial waters of all European Union countries bordering the Mediterranean — its waters are 20 times smaller than Italy’s .
In Malta, bluefin tuna farming has become an industrial activity concentrated in the hands of six companies that belong to a dozen families. The four main bluefin tuna farms — MFF, Ta’ Matthew, Fish&Fish, and Mare Blu — also have significant holdings in the real estate sector, which has seen a boom in the past decade.
Cages for fattening tuna in the eastern Mediterranean Sea (Nanni Fontana)
The center of operations is Marsaxlokk, a small fishing village on the eastern part of the island. Every day, 500 tons of frozen pelagic fish are shipped from its port to tuna cages 10 miles off the coast, out of sight of beachgoers. The docks and logistics areas, which are managed by the Maltese Federation of Aquaculture Producers, are as tightly guarded as a military zone. Access is impossible, and information is not forthcoming in the village either: Locals do not seem to appreciate people asking questions about the tuna business, which is shrouded by a mafia-like code of silence. The few who do talk do so anonymously. The export of fattened tuna represents 90 percent of the island fishery sector’s profits.
Tristan Camilleri, a biologist and consultant for the Federation of Maltese Aquaculture Producers, told us that “every year, about 13,000 tons of tuna pass through these cages.” In 2022, the Federation sold more than $200 million worth of tuna to Japan, nearly a third of the total $650 million sold by tuna farms across the Mediterranean. Fishmongers in Marsaxlokk sell fresh tuna to locals that is “stolen from cages” according to one buyer, for less than $3 per pound. In Japan, major trading companies like Mitsubishi pay $40 per pound.
After the fish finished eating, the farmers grabbed 12-caliber shotguns and shot some of the tuna in the head. Their job was to target the fish that weighed more than 600 pounds, and they did so with chilling precision.
Industrial tuna farming has had a detrimental impact on local fishermen. As a result of large quantities of organic waste released by bluefish, the tuna industry has moved its cages further offshore, to Is-Sikka tan-Nofs, an underwater reef 4 miles off the north-eastern coast of Malta. The area is rich in fish, a gold mine that had fed generations of Marsaxlokk fishermen, but the farming companies have banned other boats from the area.
“They have cordoned off the area with nets — they won’t let us through,” said Albert, a 63-year-old fisherman as he sits outside his house, smoking. “Small scale fishermen like me only get crumbs at this point. I made good money until a decade ago. Now I’m glad my son steers clear of our sea.”
Although tuna farms impose a strict level of vigilance, in July 2024 we were able to don scuba gear and join two obliging farmers as they plunged into a cage of frenzied bluefin tuna. We arrived smack in the middle of feeding time. A pump was pushing out tens of tons of fodder, which some 500 tuna gulped down as they swirled in a vortex of silvery flashes. Each fish weighed between 400 and 900 lbs and measured 6 to 10 feet in length.
We were assured that the fish would not dare touch us: Despite their size and power, they have a delicate immune system, and a simple scratch could kill them. After the fish finished eating, the farmers grabbed 12-caliber shotguns and shot some of the tuna in the head. Their job was to target the fish that weighed more than 600 pounds, and they did so with chilling precision. The shot tuna were then hoisted onto a support vessel, ready to be frozen at minus 90 degrees Fahrenheit and start their long journey to foreign markets. The other tuna dodged their dead companions with a flick of the tail and continued their mad carousel. This operation recurred about a dozen times over the next half hour.
When it was first introduced in the 2000s, the practice of fattening in captivity was seen as more desirable than catching bluefin tuna in the wild, which was thought to risk the species becoming extinct.
Tuna expend a lot of energy: They must swim to breathe and are among the fastest fish in the world, reaching speeds of 50 miles per hour. They need vast quantities of smaller fish every day to survive and can live up to 40 years. According to David Angel Martinez Cañabate, deputy director of the Ricardo Fuentes Group, which owns many tuna farms in Malta, if a tuna were allowed to roam free, “by the end of its life cycle, it would ingest a far greater quantity of small fish.” The argument is echoed among other bluefin tuna farmers and by the International Commission for the Conservation of Atlantic Tuna (ICCAT), the independent organization that monitors bluefin tuna stocks.
A diver surrounded by tuna in a fattening cage (Nanni Fontana)
ICCAT portrays tuna farms as the best way to satisfy demand for the prized tuna without killing more fish. This way, farmers can catch one tuna, fatten it up and sell it to Japan for the price of two unfattened tuna.
But stocks of small fish used as fodder for tuna are rapidly declining. Demand for these fish skyrockets during the fattening period — from July to October — and competition is fierce. In 2023, the Maltese farm MFF imported most of its fish-fodder from China and Mexico, at the risk of introducing unknown pathogens to Mediterranean tuna. “It’s a logistical nightmare,” said Charlon Gouder, the director of the consortium of Maltese tuna farmers.
It takes four weeks to drag the fish to the cages in Malta and large numbers of tuna die during the journey. “Sometimes we lose 40 percent of our load,” the captain said.
“Finding stocks of small fish has become the sector’s biggest problem,” an ICCAT inspector, who asked to remain anonymous, told us. He had just returned from two weeks of purse seine fishing on a Spanish fishing boat in international waters between Malta and Libya. “There is intense competition to snatch up as many small fish as possible,” he said, warning that the disappearance of these fish is a “clear danger” for the marine ecosystem.
“We’re depleting cheap, abundant fish to feed tuna for high-end markets,” said Marcel Kroese, a biologist and consultant on maritime policy for governments and NGOs. “It’s insane.”
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Back at the port of Valletta, we met a captain who has been working at sea for more than 40 years. He commands a Libyan purse seine fishing boat that sells tuna to Maltese farmers. His vessel had just been rammed by a Turkish fishing boat in a duel over a school of tuna in international waters. “It’s war,” he told us. “An increasingly dangerous environment.”
The way tuna is caught at sea and transported to cages in Malta is another example of the unsustainability of the business, he told us. Malta has marine trade agreements with half of Europe, and the tuna it fattens can be fished as far afield as the Balearic Sea, more than 800 miles away off the coast of Spain. It takes four weeks to drag the fish to the cages in Malta and large numbers of tuna die during the journey. “Sometimes we lose 40 percent of our load,” the captain said. “It depends on many factors, on the number of animals in the net, on the cruising speed, on the conditions of the sea. A single flash of lightning can stress them out to the point of killing them. If a storm breaks out at night, the tugboats have to point their lights into the water. In theory, the deaths should be reported to the authorities and subtracted from each boat’s quota, but this never happens.”
The ICCAT investigator confirmed this. “The cage trails more than 1,000 feet behind the tugboats, so how do you control what goes on in there?”
Tuna farming companies have been indicted multiple times: A 2017 judicial inquiry in Spain determined that Maltese cages were churning out large quantities of illegal tuna, and in 2023, the European Commission held Maltese farmers responsible for illegally shipping tuna to Croatian farms.
“It’s like any other big business,” insisted Alicia Bugeja Said. She was elected Maltese undersecretary of fisheries to counter the excessive power of industrial tuna farmers and defend the interests of small-scale fishermen, but she ended up siding with the tuna business. Controlling the industry would only curb economic growth and the creation of jobs, she argued. “But hey,” she added, “thank God not everyone can afford to eat bluefin tuna.”
This investigation was carried out with the support of Investigative Journalism for Europe.
This article was originally published in Internazionale.
✺ Published in “Issue 27: Promises” of The Dial
