Empty fish counters. That is what shoppers found when they arrived at Madrid’s Mercado de la Paz last September. The stock had not sold out. Instead, they were looking at an advertising campaign organized by Apromar, Spain’s aquaculture industry association, which wanted people to imagine a country without farmed fish.

“Seafood could become a luxury affordable only to a few,” the ads warned, before adding: “The real fortune is living in a country where aquaculture exists and guarantees fish for everyone.”

The message was straightforward: consumers want more fish, wild fish stocks are being harvested to their limits, and fish farming is the way to meet growing demand while preventing the collapse of the oceans. This same logic, producing more to catch less, drives a global aquaculture industry worth €270 billion ($311 billion), the fastest-growing food sector in the world. Today, half of all seafood products come from aquaculture, and Spain is the European Union’s largest producer by volume.

There is, however, a problem. “The industry’s sales pitch is incorrect,” says Daniel Pauly, director of the Sea Around Us project at the University of British Columbia.

The most popular farmed seafood products in Spain and other countries, including salmon, shrimp, trout, sea bass and sea bream, are fed with the very same wild fish species that aquaculture claims to be saving, thereby accelerating ocean depletion. Two-thirds of global aquaculture raises species that are fed fishmeal and fish oil, ingredients made by cooking and grinding fish caught in the wild. Before reaching the market, a farmed salmon may consume, in some operations, more than six times its own weight in wild fish.

An investigation by The Outlaw Ocean Project, a Washington, D.C.-based journalism organization, uncovered a range of impacts linked to the industry, including the loss of jobs in small-scale fisheries, chronic exposure to chemicals, preventable workplace deaths and violent protests, mostly triggered by the unbearable stench of fishmeal plants. The investigation concluded that these social and environmental costs fall largely on poorer countries where the raw material is caught and processed, far from the places where the seafood products are consumed.

In Gambia and Mauritania, the investigation documented how the industry worsens food insecurity as fish that once sustained local communities are increasingly diverted to fishmeal factories for export. On remote islands in Russia’s Far East and in China’s Xinjiang region, reports described the use of forced labor on fishing vessels, farms and in factories.

In other countries, including India and Peru, the industry was linked to at least 80 episodes of social conflict, some of them violent, typically involving labor strikes and community protests sparked by water pollution or the stench from factories processing thousands of tons of rotting fish.

For example, shrimp sold by major retailers in Spain, including El Corte Inglés, E.Leclerc and Carrefour, and raised on farms in Ecuador, is fed with fishmeal sourced from plants across Latin America that have been linked to at least five worker deaths, 20 cases of illegal fishing and more than half a dozen protests over odors from fishmeal factories, according to Bait to Plate, an online tool that tracks the seafood industry and its supply chains.

Carrefour Group said it had launched an investigation into issues related to its supply chain and would “take all necessary measures if violations are confirmed,” including potentially excluding suppliers that fail to meet its ethical and environmental standards. El Corte Inglés and E.Leclerc did not respond to requests for comment.

The investigation, which took two years to complete, mapped virtually the entire global fishmeal industry, including more than 1,400 plants operating in 64 countries, and traced supply chains from fishing vessels to processing plants, feed mills, fish farms and seafood retailers.

The study found that the fishmeal industry also contributes to geopolitical tensions. In 2021, for example, about a dozen Turkish bottom trawlers fishing illegally in the Aegean Sea allegedly attempted to ram a Greek research vessel after scientists began filming their activities. In 2018, riots broke out in Saint-Louis, Senegal, after a fisherman was shot dead by Mauritanian coast guards during what Mauritanian authorities described as a cross-border incursion by a vessel linked to the fishmeal industry.

Since the mid-1970s, Morocco has maintained military control over Western Sahara, a presence deemed illegitimate by more than 10 rulings of the Court of Justice of the European Union. Nevertheless, Moroccan vessels routinely fish in Western Saharan waters and process their catches into fishmeal at plants located in the territory before exporting it to aquaculture farms around the world labelled as Moroccan.

In 2020, a violent confrontation involving several trucks, many of them carrying fish and fishmeal from Western Sahara, led to the collapse of a 29-year ceasefire. Until 2024, a fishmeal plant in Western Sahara supplied fishmeal to Irida, a company that manufactures feed for many fish farms in Greece, including those supplying farmed sea bream and sea bass to Mercadona, Spain’s largest supermarket chain. Irida and Mercadona did not respond to requests for comment.

A significant share of the fishmeal used by Spanish fish farms, around 128,000 metric tons in 2024, is imported, linking Spanish consumers to these hidden and cross-border social impacts. Some 70% of Spanish aquaculture production consists of bivalves such as clams, oysters, scallops and mussels. These species are comparatively more sustainable because they generally do not require feed and need relatively little land and freshwater. Among species whose production depends on fishmeal, the most common in Spain are European sea bass and gilthead sea bream.

The investigation examined more than 2,400 vessels involved in fishmeal production operating in the waters of at least 30 countries. Most vessels in the global fishmeal fleet were purse seiners or trawlers, which use large nets to capture dense schools of fish, indiscriminately sweeping up substantial amounts of bycatch and non-target species. At least half of the species landed by the vessels analyzed had been classified as “overexploited” by scientific studies.

More affordable products

Modern aquaculture also has its benefits. In India, for example, it is a key source of employment, especially for women. In Bangladesh, its expansion has helped drive down prices, making seafood more affordable for lower-income households. The industry’s carbon emissions are also considerably lower than those from beef or pork production.

Bivalve farming has an especially low carbon footprint. As early as 2022, roughly one-third of global aquaculture production required no external feed inputs. Even so, more than two-thirds of farmed seafood today still depends on feed from the sea. According to the Food and Agriculture Organization of the United Nations, global fishmeal consumption is projected to increase by nearly 10% between 2022 and 2032.

Asked about concerns over the sustainability of her sector, Véronique Jamin, spokesperson for IFFO, the international fishmeal and fish oil association, said aquaculture is “the most efficient animal protein system.” She added that “sustainability frameworks will not work if they ignore the economy of the real world,” and argued that seafood companies must respond to “what people actually want to buy and eat.”

Researchers have explored alternative protein sources such as algae, cassava waste, black soldier fly larvae and even single-cell proteins derived from fungi or bacteria, but none are yet affordable at scale. For now, the pattern remains the same: wild fish are caught and converted into feed, while the costs of this production are borne elsewhere.

The investigation revealed the hidden role that forced labor and land dispossession play in the expansion of China’s aquaculture industry. China now farms more than four times the amount of fish it catches from the wild. One of the industry’s fastest-growing regions is the mountainous and desert interior of western China, particularly Tibet and Xinjiang, two areas known for intense political repression.

The investigation identified more than 1,000 aquaculture farms in Xinjiang and Tibet producing farmed seafood worth an estimated €436 million ($502 million) annually, much of it exported to more than a dozen countries. China’s push to expand fish farming in these regions is facilitated by extensive state repression, including widespread land seizures, intensive surveillance, and the imprisonment of tens of thousands of people. European Union legislation does not specifically target China, but it does prohibit the importation or sale within the EU of products made using forced labor.

Seafood companies are also facing growing legal challenges related to problems in their supply chains. Since 2020, at least nine lawsuits alleging deceptive marketing practices have been filed against six seafood companies across six U.S. jurisdictions. The cases center on a common pattern: marketing claims portraying products as sustainable or ethically sourced despite supply-chain evidence suggesting otherwise.

Plaintiffs challenged terms such as “sustainable,” “eco-friendly,” “all natural,” “wild-caught,” and “from the coast of Maine,” as well as claims of superior labor standards. The Outlaw Ocean investigation reviewed more than 500 seafood companies making similar, and in some cases even stronger, marketing claims and found that more than half had documented violations or irregularities within their supply chains.

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Every day, a community garden and a seaside promenade are all that separate Carmen Gutiérrez from Sardinero Beach in the Spanish city of Santander. As director of the Cantabria School of Film and Television, she could practically jump onto the sand from the privileged location of its main campus in Santander. Even so, she tries not to do so when she has an afternoon of work at the computer ahead of her.

“Because the beach is tiring,” she says.

In fact, if she returns home after a few hours by the sea, “I don’t feel like unpacking my beach bag. I just want to lie down on the sofa,” she admits.

The feeling will be familiar to any holidaymaker. Although, in theory, few activities seem more relaxing than spending hours stretched out on a towel under the sun, soothed by the breeze and the sound of the waves, it is common to return from a day at the beach feeling drowsy and low on energy. But how is it possible to end up exhausted after enjoying what is supposed to be the ultimate summer retreat?

A body that never goes on vacation

“People think the body is resting, but it’s doing enormous metabolic work,” Javier Ceballos, a sports medicine specialist and former doctor for Racing Santander, tells EL PAÍS.

Ceballos has been retired for several years and is a well-known figure in Santander. He spends much of his time playing beach paddle, a traditional paddle game popular along this coastal region.

Ceballos attributes the sensation of beach fatigue to three physiological mechanisms. The first is thermoregulation. “When ambient temperature rises, the body’s priority is to keep our temperature stable at around 37ºC [98.6ºF],” he says. To achieve this, the body activates a complex physiological system that consumes energy even if we are motionless under a beach umbrella. “While we’re lying on the towel, the body is working to prevent overheating.”

When the hypothalamus, the brain’s thermostat, detects excess heat, it instructs superficial blood vessels to dilate and activates sweating. As sweat evaporates, it helps cool the body. But although these processes often go unnoticed, they come at a cost. “The body is constantly making adjustments: blood flow to the skin increases, the heart has to work harder, and all of that ends up producing a feeling of fatigue,” the expert explains.

That demand is compounded by fluid loss. “Even if you’re still and lying down, you continuously lose fluid because of the heat, the breeze and sweating. Even mild dehydration makes the heart work harder and that also contributes to tiredness,” says Ceballos.

According to the Mayo Clinic, exposure to high temperatures — especially when combined with high humidity — can lead to a range of heat-related disorders, from muscle cramps to heat exhaustion and, in severe cases, heat stroke, a potentially life-threatening medical emergency. Symptoms include fatigue, dizziness, weakness, headache, nausea and difficulty concentrating.

Young children and older adults are the most vulnerable groups, since their ability to regulate body temperature is less effective, Ceballos warns. “In older people, the sensation of thirst appears later, which is why it’s so important to drink before you feel thirsty.”

The third mechanism involves the body’s defense against solar radiation. Even when sunburn does not occur, ultraviolet rays can generate oxidative stress and damage skin cells, triggering an inflammatory response. “The sun acts as an aggressor and the immune system responds,” says the expert.

As part of this process, the body releases immune-signaling molecules known as cytokines, which are also associated with the fatigue experienced during some infections. “They send signals that promote tiredness and force the body to rest in order to repair the damage,” Ceballos adds.

The beach is also not as passive an environment as it appears. Fatigue may begin even before setting foot on the sand. During summer, people often sleep poorly because of the heat or changing schedules, and waking up early to secure a good spot on the beach hardly helps.

Then comes carrying umbrellas, coolers, and beach gear, a physically demanding task, especially for those who lead sedentary lifestyles. And after that there are walks, swimming, games with children, or activities such as paddle and frisbee. Even walking on sand requires considerably more effort than many people realize.

An Italian study estimated that walking on sand requires nearly twice as much energy as walking on a firm surface. Researchers attributed the difference to the fact that the body recovers movement energy less efficiently with each step on sand, forcing the muscles to work harder to move forward.

“You have to keep lifting your foot because it sinks, and that requires a lot more energy,” says Ceballos, adding that he becomes particularly aware of this when he is playing beach paddle.

Precisely because he understands this physiological toll so well, Ceballos limits his time at the beach. “I stay two hours, two and a half at most.” His routine consists of playing beach paddle for just over an hour, staying hydrated throughout, going for a swim, enjoying a little sun while always protected, and then heading home.

Recommendations

To reduce the strain, Ceballos’ recommendations are simple. The first is to hydrate before feeling thirsty. “A sip of water every hour is essential.” He also warns against some false remedies: “Alcohol and sugary juices dehydrate you more. I would drink water and perhaps a beverage with electrolytes — sodium and potassium — but without sugar or not excessively sugary.”

He also emphasizes another basic rule: avoid the hours when solar radiation is strongest. “The worst hours are between 12 p.m. and 4 p.m.” He adds other precautions: avoid heavy meals, “which divert more blood to the stomach,” use appropriate sun protection, and take regular breaks in the shade.

Everything suggests that beachgoing should be enjoyed in moderation. “It’s not psychological; the body is working constantly,” he summarizes.

In fact, many people report feeling even more exhausted the following day. Ceballos explains that cellular repair, rehydration, and the restoration of the body’s internal balance all take time. “It’s the bill the body charges you.”

Perhaps that is why Carmen Gutiérrez has adopted her personal rule. Even though Sardinero Beach is only a few steps away from her workplace, she avoids going there if another afternoon at the office lies ahead. Simply because, as she puts it, “it’s tiring, and it gets everything sandy.”

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They share their dreams on an outdoor futsal court that’s been fenced off and turned into a makeshift camp by residents of the La Reina neighborhood in Ceuta. Some 350 women and children who arrived in the Spanish enclave city after swimming from Morocco 11 days ago sleep in the camp every night. They sit here waiting, on the ground, or, if they are lucky, on a rug.

They are waiting because, beyond these four fences and the two men guarding the entrance through the night, the world seems a safer place. Among them are children who dream of becoming footballers, studying technology or training as nurses. Children who have crossed the sea and who, without realizing it, have become the subject of a political debate before anyone has taken the time to listen to them.

EL PAÍS asked them to write letters so that politicians, especially those who say they do not want them in Spain, could learn about their aspirations. They do not write about borders or laws. They write about their dreams, because sometimes behind the word “migrant” there is a child who has not yet stopped imagining who they want to become.

Hello:

My name is Ismaíl. I want to stay in Spain to fulfill my dream of becoming a great footballer. If you let me stay in your country, you would help me a lot. With a bit of luck and a lot of hard work, one day I could become a talented player and represent Spain in the national team.

Ismaíl is 12 years old and completely alone in an unfamiliar country where he does not speak the language. Even so, he smiles often, proudly revealing the gaps where some of his teeth have yet to grow in. He arrived in Ceuta by swimming alongside his 20-year-old brother. He has not seen him since.

He sleeps on the ground. To wash, he goes to the vacant lot beside the camp and pours water over himself, fully clothed, using a pink beach bucket. Afterwards, the bucket passes from hand to hand among the women and children living there.

The little boy knows nothing about the controversy sparked by the arrival in Ceuta of hundreds of unaccompanied minors. He does not know that the Spanish Minister of Youth and Childhood, Sira Rego, has convened a meeting this Thursday to address the crisis in Ceuta. He also does not know that the far-right political party Vox is against receiving them. He knows nothing of the political arguments, the borders or the language others have chosen to use when discussing his future. But despite his young age, he is not surprised this is the case. He says he “knows very well that politicians in Spain do not want Moroccans to enter their country.”

Beside him sits 15-year-old Maryam. Her dark hair is tied back in a braid and she is still wearing the clothes she arrived in. With a ballpoint pen, she writes in Arabic in a notebook:

I wanted to come to Spain to work and help my family. I dream of finishing high school and becoming a nurse so I can help other people. Please regularize my status so we can build a better country together. We will show that we are worthy of your trust. We only want a better future.

She had been thinking about coming for three years. On July 30, at 4 a.m., she decided to try. She left Tetouan with a cousin and two friends. She was frightened because she is not a strong swimmer and knew that leaving her mother behind would not be easy. When she reached Spain, the first thing she did was log on to Instagram to talk to her mother. She had not warned her she was leaving and wanted to apologize. “She was very worried, but when I told her I was okay, she wished me all the success in the world because she understands that coming here had always been my dream,” says Maryam, smiling shyly when asked why she did not tell her mother about her plans.

Samia, 20, was a teacher in Morocco. Now, after arriving in Ceuta by swimming, she acts as a translator for Maryam. She explains that there are far-right parties that oppose relocating migrant minors to other regions in Spain. Maryam opens her eyes, surprised. “But why don’t they want to give us papers?” The question comes out plainly, without any understanding of political parties or political rhetoric. Samia laughs.

The hours drag on beneath the scorching heat. The ground burns when someone tries to sit down. In the vacant lot just outside the enclosure, two workers are attempting to install a portable toilet. It will be only the second for the more than 350 people taking refuge here.

The city council has just provided it after repeated appeals from the neighborhood association president, Abdellah Mustafa, who also spearheaded the idea of turning the soccer pitch into a safe haven for migrants.

Next to the toilets, a woman washes clothes beside a stroller while her baby crawls across the ground. When the mid-afternoon sun becomes unbearable, the child bursts into tears. Nearby, several girls sit exhausted on the curb, shaking out their clothes.

Despite everything, they are the lucky ones; at least they have a place to spend the night. More women continue to arrive asking whether there is any space left, but the enclosure is full. There is no room for anyone else. The volunteers guarding the site cannot take them in, and they will have to spend another night out in the open. Save the Children estimates that more than 1,000 minors in Ceuta are sleeping on the streets outside the official protection system.

Mohamed and his mother watch the scene unfold while playing clapping games to pass the time. The boy is eight years old, with large, dark-brown eyes. Whenever someone asks him a question, he falls silent for a few seconds, thinking carefully about his answer, mouth slightly open and cheeks flushed, before finally speaking.

Until they found shelter here, Mohamed and his mother were sleeping on the street, outside a house. He says he felt terrified every time he saw the soldiers deployed across Ceuta.

Like Ismaíl and Maryam, Mohamed also writes his dream on a piece of paper:

I want to be a police officer and work to help my mom. I want to get the documents I need because I deserve a chance to prove myself.

In the meantime, he waits. He cannot explain why, but he is convinced this limbo will last another two weeks. Until then, he will follow the same routine every day: have breakfast, find another child to play with, eat lunch and wait for another day to pass. “And then the same again,” he says

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