A tall, slim fin slashes the Mediterranean’s surface for a split second and the bait fish is gone, provoking a few gasps and some nervous laughs from the 40 or so snorkellers lined up to enter the open-water pen.
Most wear wetsuits and clutch masks and air tubes, a few are in swim shorts and goggles. Some have already had a beer or a glass of wine. The midday sun is out, The Trammps’ Disco Inferno is playing from the catamaran’s speakers and now people are climbing down a stepladder into a ring of netting that stretches 35 metres down into the sea near the Spanish port of L’Ametlla de Mar, about 80 miles from Barcelona.
Inside the pen are about 500 bluefin tuna. Caught from the wild, they are being fattened for slaughter, a process known as ranching. The snorkellers, who have paid for a tour run by a company called Balfegó, have about 45 minutes to swim with the fish.
Balfegó’s core business is tuna farming. It is a sector that has received a lot of criticism over concerns about fish welfare. “The tours are a way to help people understand how we farm tuna,” says Begonya Mèlich Bonancia, a Balfegó spokesperson. “They are educational. That’s the main aim.”
Balfegó is one of just a handful of companies offering fish-farm tourism but environmentalists are concerned that it is a sector with the potential to grow. It could become another part of the wildlife tourism experience alongside whale watching and shark diving.
“People who like to dive like to be surrounded by fish and fish are rarer in the sea now,” says João Saraiva, a behavioural biologist who works with Portugal’s Centre of Marine Sciences in Faro, Algarve. “It’s just a reality that it’s harder to get the experience of swimming around in large schools of fish now.”
On the short boat ride from L’Ametlla de Mar to the pens, a video has already explained to the swimmers that bluefin can reach top speeds of 50mph and can never stop swimming because their breathing system requires a continuous flow of oxygenated water.
In the pen, snorkellers hang on to the ring’s edge, peering down at the fish speeding back and forth, huge silvery-blue bodies, each with a row of yellow finlets near the tail. They have not yet reached slaughter weight but already each fish is worth thousands of pounds.
Bluefin are known for their vast ocean migrations and can grow up to four metres long. The fish under the snorkellers are about half that size. Their current weight, according to Mèlich Bonancia, is about 180kg. They won’t be slaughtered until they reach 200 to 250kg.
Letting go of the pen’s edge, a few swimmers are making tentative dives. A woman with a camera on a selfie stick goes deeper, neatly positioning herself near pieces of suspended bait. Within seconds a bluefin torpedoes toward her, swallows the bait and is gone. She has her shot.
Fish farms are regularly criticised over water pollution – mostly from the fish poo and uneaten feed – and for the misuse of smaller fish as feed (experts say it takes 20kg of small fish such as sardines to produce 1kg of farmed bluefin tuna).
But it is fish welfare that primarily concerns the farms’ critics. “Bluefin tuna are highly migratory animals and are being kept in relatively small enclosures, which is likely to be stressful,” says Wasseem Emam of Ethical Seafood Research, an advocate for better welfare and conservation in aquaculture and fisheries.
Adding tourists to the mix, he says, increases his concern. “I have serious doubts about whether we should be farming them in the first place so why are we making them into an entertainment spectacle?”
Mèlich Bonancia, however, rejects the criticisms. She says that Balfegó’s bluefin have plenty of space, that tourists are only allowed into one pen where there are a few hundred fewer fish than normal, and their feed ratio, at most, is 8kg of wild fish for each kilo of tuna.
Tuna slaughter is another point of pride for the company. While smaller species of farmed fish such as sea bream and sea bass are lifted out of their pens, risking crushing, and then suffocated to death in ice-water tubs, farmed tuna are dispatched by spike gun while still in the sea. The spiking process is swift and results in better quality meat, the company says. To alleviate the stress caused to other tuna, Mèlich Bonancia says slaughter is rotated between their 20 pens, giving the fish a few weeks to recover.
For those keen to swim with farmed fish, a more important point may be that Balfegó appears to have cornered an unusual market. Tunipex, a Portuguese rancher that ran a dive operation for a few years, closed during the pandemic and has not reopened.
A Greek dive centre partnership with a sea bream, sea bass and meagre farm that, until last year, allowed tourists to swim in one pen and around others, has paused operations due to issues around using a space designed for fish farming for tourism. The Greek government confirmed it is working on the new law, which is waiting final ministerial approval.
More fish farm tourism might be good news for divers who’ve never known an ocean full of creatures, but not for the fish, says Saraiva. “They are better off without people.”
