Many diets that are better for our health, and the planet’s, call for eating more fish. Where will it all come from?
THE LIFE OF an Atlantic salmon is one long, gruelling road trip. Born in coastal rivers in Europe, North America, Iceland and Russia, once the young salmon hit adolescence they head out of their natal waters to the frigid North Atlantic, where they gorge themselves on squid and krill. Once they have built up their energy reserves, the salmon use the Earth’s magnetic field and their finely honed sense of smell to find their way back upstream to the exact same riverbed they were born in, where they spawn the next generation of salmon. By the end of this journey, which can cover several thousand kilometres, the fish are so exhausted that many of them perish. A couple of years later the next generation of salmon will be old enough to start the cycle all over again. You’re born, you swim thousands of kilometres, you die.
But inside a sprawling white-panelled factory on a sun-baked former tomato field south of Miami there are hundreds of thousands of Atlantic salmon leading lives that would leave their wild relatives utterly baffled. These salmon are born indoors and die indoors, spending their lives cycling between a series of vast circular tanks that together hold more than 60 million litres of water. Some of the tanks are filled with freshwater, to mimic rivers, while others contain seawater drawn from the Atlantic Ocean, which lies 24 kilometres to the east of the building. According to Thue Holm, chief technology officer of Atlantic Sapphire – the Norwegian firm building the plant – by the end of 2022 the facility located in Homestead, Florida, will be able to produce approximately 10,000 tonnes of salmon a year. When it is completed it will produce a sizeable chunk of the US demand for fresh salmon.
As you might expect from one of the people behind the world’s biggest experiment in land-based fish farming, Holm is convinced that the future of food lies in the oceans. He might have a point. Oceans cover 71 per cent of the planet’s surface, but at present provide us with only about two per cent of our total food and around 15 per cent of all the animal protein consumed by humans. According to the EAT-Lancet report – a wide-ranging study that attempted to pinpoint what the best kind of diet would look like, in terms of the planet’s health and our own – seafood is the one source of animal protein that we should be eating more of. The report estimated that a global shift to a “planetary health diet” that emphasises fruits, vegetables, nuts and wholegrains would also require more than double the current levels of fish production.
Fish aren’t simply a much healthier source of protein; they have a relatively small impact on the environment too. Compared to most land animals, the Atlantic salmon swimming in Holm’s farm are remarkably efficient machines. Since they are cold-blooded and are supported by the buoyancy of water, fish can channel more of their energy into growth, which means they need fewer calories from food than other livestock. It takes about 1.15 kilograms of fish feed to produce a kilogram of farmed salmon – significantly lower than any commonly farmed land animal. It’s the same basic reason why lab-grown meat companies are opting to grow beef in bioreactors: more efficient methods of meat production should come with lower greenhouse-gas emissions. In a world of 9.7 billion people in need of a nutritious, readily available and sustainable source of protein, fish look like one of our best bets.
So where are all these fish going to come from? Not the open ocean, where almost 60 per cent of widely eaten fish are already being fished at their maximally sustainable limits. Wild-capture fishing has chipped away at the ocean’s fish populations, leaving many species badly depleted. In the United States, salmon used to be found in almost every single coastal river northeast of New York’s Hudson, but now the country’s only remaining wild populations occupy a handful of rivers in Maine. The same story repeats itself almost wherever you look in the water. In 2010 the total mass of Pacific bluefin tuna capable of breeding reached its lowest-ever recorded level – just 11 per cent of its 1952 numbers. In 2015 the World Wildlife Fund released a report revealing that overfishing, habitat destruction and climate change had caused fish populations to fall by nearly half between 1970 and 2012. The oceans aren’t able to meet our current demand for fish, let alone feed future generations.
“Hunting and gathering out of the ocean is a joke. We haven’t hunted and gathered most of our food on land for three thousand years,” says Kevin Fitzsimmons at the University of Arizona’s College of Agriculture and Life Sciences. The alternative, to Fitzsimmons, is obvious. Rather than pluck fish out of the sea, why not repeat what we already do with livestock and crops: grow them intensively at scale? Globally fishing has been heading in this direction for decades. In 1961 farmed fish made up about five per cent of the world’s entire seafood production, but since the late 1980s fish farming, also known as aquaculture, has boomed. In most aquaculture, farmed fish are kept in net pens – large circular cages usually made from steel or plastic, anchored to the ocean floor or the bottom of freshwater ponds or lakes. In 2013 the volume of seafood produced in this way overtook wild capture for the first time, and since then the gap has continued to grow. Since the mid-1990s the world’s total production of wild-caught fish has plateaued, while the amount of fish coming from farms has more than tripled. The aquaculture industry has grown up exceptionally fast. “What we did with terrestrial agriculture in three thousand years we have done in aquaculture essentially in the last thirty,” says Fitzsimmons.
But if the history of farming has taught us anything, it is that intensifying livestock production comes with major drawbacks. In Asia vast stretches of mangrove forest have been cleared to make way for shrimp farms, leaving coastlines more vulnerable to erosion and removing a vital carbon sink. Moreover, keeping so many fish in close proximity concentrates pollution in the form of uneaten food, waste and dead fish. This then leaks into nearby waters, disrupting the delicate ocean ecosystems. Cramped net pens are also a perfect breeding ground for diseases and pests, and there is the extra danger that disease endemic in farmed fish could spill over into wild populations. In 2012 salmon farms in Scotland lost nearly 10 per cent of their total production to amoebic gill disease and other infections that raced through net pens, killing more than 8.5 million fish. In August 2019 Denmark’s environmental minister deemed offshore aquaculture so environmentally risky that she called a halt to all new fish farms in the area and prevented existing farms from expanding.
Many fear that net pens will end up becoming the cattle feedlots of the ocean – pollution-generating floating factories whose only aim is to churn out cheap meat at terrific scale. “We have made some of those mistakes. Stuff we should have learned from terrestrial agriculture that we had to relearn in some cases,” admits Fitzsimmons. But the industry is still in its infancy, and aquaculture farmers are eager to prove that they are the go-to model for efficient and sustainable food production. The race to fix aquaculture will require rethinking which fish we put in net pens, what we feed them and how the farms operate. And for Thue Holm, it all starts with taking the fish out of the ocean altogether.
THERE ARE A few reasons why it might make sense to grow Atlantic salmon thousands of kilometres away from their natural home in the Norwegian fjords, which are still the centre of the 2.5-million-tonne-a-year salmon-farming industry. Growing fish closer to the people who eat it cuts down on transport costs; farming on land reduces the amount of pollution sent directly into the water; and there is no chance that the salmon will escape through a rip in the net and return to the sea. But there is another factor that pushed Atlantic Sapphire halfway across the globe to south Florida: sea lice.
Sea lice are the scourge of the salmon aquaculture industry. The tiny crustaceans hook onto the fish’s scales and feed off its skin and blood to survive. In the wild, a salmon can shrug off one or two sea lice without much fuss, but a fully grown female salmon louse can produce more than 1,500 eggs in its lifetime and, in the densely packed environment of a net pen, populations quickly spiral out of control. A dozen sea lice can kill a salmon; smaller infections leave fishes with bright-pink patches of raw flesh around their gills, rendering the fish completely unmarketable. As a result, these pernicious parasites cost the salmon aquaculture industry about £400 million a year. In an effort to keep sea-lice numbers down, salmon farmers have tried bathing salmon in hydrogen peroxide and supplementing net pens with cleaner fish such as wrasse, which happily nibble away at the parasites. In Norway a start-up called Stingray Marine Solutions markets a sea-lice-zapping robot that kills the crustaceans by hitting them with short bursts of light that are harmless to the fish. The technology is currently being used in more than 150 Norwegian salmon pens.
Another potential solution to the sea-lice con- undrum is to farm fish in tanks on land. “All of the biological challenges you have in the sea, you can avoid [on land],” says Atlantic Sapphire’s Thue Holm. No diseases brought in by wild fish (or transmitted by farmed fish to the wild), no algal blooms poisoning fish, and no sea lice. “We don’t vaccinate our fish. We don’t ever use any antibiotics. And it’s impossible for sea lice to survive in our system,” states Holm. In 2011 Atlantic Sapphire’s co-founders, Johan Andreassen and Bjorn-Vegard Lovik, partnered with Holm to build their first land-based salmon farm in a small Danish town called Hvide Sande. It now produces 2,400 tonnes of salmon every year. With its Florida farm, Atlantic Sapphire is attempting to take the blueprint of their Danish farm, scale it up and place it right on the doorstep of the nation that consumes more Atlantic salmon than anywhere else in the world.
Atlantic Sapphire settled on Homestead, Florida, because of the location’s unique geography. Since salmon start their lives in freshwater before migrating out to sea, land-based farms need to have access to both seawater and freshwater for the fish to grow in. South Florida happens to sit atop ample stores of both: the Biscayne Aquifer provides the region with its freshwater while parts of the Floridan Aquifer are filled with salt water. The Homestead farm draws water from both of these sources to fill its tanks and then pumps the waste water into the boulder zone – a layer of permeable rock that connects to the Atlantic. Over thousands of years, that water will gradually filter through the rock and head back to the ocean.
This elaborate set-up is crucial to mimicking the salmon’s natural lifecycle. The farm buys salmon eggs, which are kept in cool, dark conditions until they hatch and the baby fish are transferred to a freshwater tank until they reach 100 grams. At that point, farm technicians simulate winter by turning down the lights for most of the day and the fish are moved from the freshwater tanks into salt-water units, eventually passing through ten different systems in their lifetimes. After 20 months the fully grown fish are piped from their final tank into the farm’s processing facility to be stunned, gutted, graded for quality and packaged, ready to be loaded onto trucks. Throughout the entire process, from hatching to their unceremonious entrance into the processing area, the fish never get a single glimpse of the outside world.
But keeping fish in such tightly controlled environments is fraught with technical challenges. Water in the tanks must be circulated, to keep the fish swimming against the current; oxygen must be pumped in, so they can breathe, and waste filtered out to stop the water becoming toxic. If something goes wrong, thanks to a faulty pump or a dodgy sensor, you could have a disaster on your hands. In February 2020 unusually high nitrogen levels killed off 227,000 salmon in Atlantic Sapphire’s Danish farm.7 Four months later the company was forced to harvest 200,000 salmon from its Homestead farm before they were ready, after construction work near a tank distressed the fish.8 Despite these risks, the Homestead farm is just one of at least 20 different land-based fish farms currently in operation or being built in 11 different countries by various firms.
Not everyone in the industry is convinced that land-based farms are the future of fish production, however. “It’s kind of extraordinary that such a large amount of investment capital is going into these projects when there is no really successful working example of a large-scale [land-based] Atlantic salmon farm,” says Josh Goldman, a man who has spent more than 30 years trying to find a better way to farm fish. Despite his scepticism about the viability of land-based salmon farming, Goldman has been experimenting with the technology longer than almost anyone in the business. In 1990 he opened an indoor fish farm on the banks of the Connecticut River, close to a village called Turners Falls in western Massachusetts. Still in operation today under different owners, it is one of the world’s largest and longest continuously running indoor fish farms.
Goldman’s obsession with fish farming started when he was in high school reading Frances Moore Lappé’s 1971 book Diet for a Small Planet – one of the first popular books to emphasise the link between our culinary choices and the environment. A few years later Goldman built a farm with fish and vegetables growing alongside each other (an approach called aquaponics), close to his student dorm at Hampshire College in Amherst, Massachusetts. Years after graduating, he wound up starting companies that farmed tilapia and striped bass, selling the finished product to a group of Chinese restaurant owners who were after a steady stream of fresh, locally sourced fish.
While the Chinese-restaurant gig paid the bills, Goldman had a much bigger plan in mind. He looked at what most fish farmers were producing and saw that the industry was full of compromises. Some fish we farmed because we were already accustomed to eating them, others were cheap and easy to grow in pens. But the ocean is bursting with diversity. There are an estimated 30,000 fish species alone. Surely there was a better fish out there for farming? In 2000 Goldman set out on the hunt for the perfect farmed fish: one that could be easily domesticated, had a low environmental footprint and was so delicious that people would come back for more after they had tried it. For three years he trawled the world in search of a better fish. He raised 30 different species, selling the excess fish to the Chinese restaurant owners, before he hit upon his perfect catch: barramundi, a fish found widely in the Pacific, but rarely eaten outside Australia and South Asia. In 2004 he co-founded a company, Australis Aquaculture, and started farming barramundi in Turners Falls.
Barramundi ticked all of Goldman’s boxes. “It’s really been built for farming in a very cool way,” he says. The fish are fast-growing, lay eggs frequently and have large gills, which mean they thrive in low-oxygen environments. Their largely vegetarian diet also cuts down their environmental impact. And they happen to taste good, too: sweet and buttery, with a flaky texture like sea bass. Goldman became barramundi’s biggest proselytiser: convincing high-end chefs to start cooking with the fish, and nudging retailers to market it as a healthy, sustainable source of protein. Soon he was fielding calls from big supermarkets wanting to stock as much of his barramundi as they could get their hands on.
As the popularity of his barramundi grew, Goldman began to realise that his indoor farm could only take him so far. To keep his fish healthy, the water in each of his 500,000-litre tanks had to be recycled twice every hour, and the Turners Falls plant had ten of them, plus 35 smaller tanks. On top of that, each tank needed to be topped up with a significant amount of freshwater each day. All this water hauling makes indoor fish farms huge energy hogs. According to one analysis, fresh salmon produced in an indoor farm in the US has double the carbon footprint of salmon produced in a Norwegian net pen. When Goldman ran the numbers he realised that it would cost him twice as much to grow his barramundi indoors in the US as in a net pen in South-East Asia. So in 2006 he found a site much closer to his barramundi’s natural habitat: the tropical waters of Van Phong Bay in central Vietnam.
“I realised that this was a place where we could really execute a model that’s going to work for this fish,” Goldman says. Today he has more than 60 net pens in the area, with the largest each holding about 150,000 fish – much bigger than his tanks at Turners Falls. Although he never set out to be a large net-pen farmer, Goldman states that intensifying production in the fish’s natural habitat makes more environmental sense than endlessly expanding land-based farms. “If we want to preserve the natural world and restore ecosystems and manage carbon, in some ways, intensification and efficiency are really the smart play so that more natural systems can be returned to non-farming uses.” As long as net pens are built and maintained with the local environment in mind, they don’t have to become an ecological burden, he says.
Goldman is also trying to do for the ocean what startups like Small Robot Company are doing for fields: using data to reduce the overall resource footprint of the farm. When the barramundi are being fed, farm technicians watch live camera footage from inside the net to ensure that no feed is falling past the fish. As soon as it looks as if the fish are leaving the pellets, they stop feeding them. Each of the nets is also only farmed for a maximum of a year before being moved, to give the ocean floor time to recover from the pollution the pens release into the water. “You don’t ever let it get to a tipping point,” Goldman says.
Another way to reduce the environmental impact is to grow seaweed alongside the fish. When the nets in Vietnam aren’t being used for fish, Goldman experiments with using them to grow seaweed that can be turned into a thickener for milkshakes, yoghurts and ice cream. When seaweed grows, it takes in the nitrogen and phosphorus released from fish waste, balancing out some of the impact of the net pens and also releasing oxygen back into the water. Off the coast of Cape Cod a start-up called Greenwave is growing seaweed alongside scallops, muscles, oysters and clams in ocean farms where nutrients are cycled directly between the growing organisms, with no need for external inputs. In Vietnam, Goldman is also hoping that his seaweed could have a big impact elsewhere in the food chain. Through a spin- off project called Greener Grazing, he’s growing a type of seaweed called Asparagopsis, which has been shown to dramatically slash methane emissions from cattle when added to their diets in small amounts. (The realities of cattle farming, however, make this less of a slam dunk than it might seem). Greener Grazing has already established a seedbank of different Asparagopsis varieties and is currently working out where the best place to grow the seaweed is, and how it could be combined with aquaculture to close the resource loop in fish farming.
No matter how much seaweed you add to a fish farm, it doesn’t solve the problem of what to feed them. One of the awkward ironies of the aquaculture industry is that its existence hinges on fish taken from the ocean. Between 1950 and 2010 more than a quarter of all fish caught in the wild weren’t destined for our dinner plates at all. Instead they were turned into fishmeal or fish oil, the majority of which goes towards feeding farmed fish. Estimates put the proportion of wild-caught fish that end up going towards fish farms at closer to 12 per cent today, which still adds up to millions of tonnes of fish every year that are taken out of the ocean, only to be fed to farmed fish elsewhere in the world. Most of these fish are small forage species that do the vital grunt work of the ocean: feeding on plankton right at the bottom of the ocean food chain and channelling that energy all the way up to marine predators such as tuna, sea bass and dolphins. But for the aquaculture industry, these fish are a vital source of the protein and fish oil that their farmed fish and shrimp need in order to grow and survive. Without wild-caught fish, the aquaculture industry would be literally dead in the water.
People in aquaculture have known for years that their reliance on wild-caught fish isn’t the best look for an industry whose very existence is partly due to the environmental costs of dredging our oceans to fill stomachs. In 2015 Kevin Fitzsimmons from the University of Arizona helped set up the inaugural Fish-Free Feed Challenge, which, in its latest iteration, offers a $70,000 (£53,000) prize to the three teams that can sell the greatest amount of fish-free feed to salmon, shrimp and other carnivorous-fish farms. In Van Phong Bay the fishmeal fed to Josh Goldman’s barramundi is produced from bycatch – unwanted fish accidentally caught by fisherpeople – but he’s on a constant mission to improve what he’s feeding his fish. Each year he conducts between five and ten different feed trials, tweaking the formulation of his feed to see how it affects fish growth.
ANOTHER ANSWER TO the fishmeal problem might lie in a vertical farm nestled in the French wine-growing region of Burgundy. There Antoine Hubert runs a farm that specialises in just one crop: mealworms. Inside, the blocky 3,000-square-metre building is stacked high with trays of writhing mealworms, the larvae of the Tenebrio molitor beetle, half of which will go towards replacing fishmeal in fish feed, with the other half being used in pet food. Currently the farm produces about 1,000 tonnes of product per year, but this is just a testing ground for a much larger facility currently under construction in Amiens in northern France. By the time it is up-and-running in late 2021, Hubert, who is the co-founder of the insect-farming start-up Ÿnsect, expects the farm will be able to produce 100,000 tonnes of mealworm-based products every year.
From an insect farmer’s perspective, mealworms are an unusually useful animal. The bugs feed happily on crop waste from wheat, barley or potato farms and processing plants and, unlike grasshoppers – another much-touted source of animal protein – they don’t make a habit of jumping out of the trays they live in. After about two months growing in their trays in the largely automated factory the mealworms are steamed to death, sterilised, mechanically crushed and turned into protein meal and insect oil destined for use in animal feed. The manure they produce doesn’t go to waste, either. It can be turned into nutrient-packed fertiliser that makes it an attractive replacement or supplement to existing agricultural fertilisers. In summer 2020 Ÿnsect became the first company in the world to obtain marketing approval for an insect-based fertiliser, which Hubert says will soon be sold in garden centres across France.
“Everything that goes in comes out into one of these three products,” says Hubert – manure, insect protein and insect oil. As well as helping fish farmers cut down their carbon footprints (Hubert hopes that his Amiens plant will be certified carbon negative), it looks as though fish feed containing mealworm might help fish grow even more quickly than conventional fish feed. One research group found that after six weeks shrimp that had been fed varying amounts of mealworm had put on more weight than shrimp that had eaten a diet supplemented only with fishmeal. Another study that involved replacing fishmeal with mealworm for sea bream also saw increased fish growth. Some of Ÿnsect’s current customers have now completely replaced fishmeal with mealworm, while others use a mix of the two.
For Hubert, fish feed is just the beginning. The animal-feed market is huge – about 1.1 billion tonnes every year – and mealworms could make an attractive supplement for pig and poultry diets, too. His next step is to try and breed even better mealworms with increased protein content or extra minerals. “Now we’re going to start comparing different strains of this molitor beetle,” he says. “We think we can do something interesting by maybe crossing different strands together and highlighting some genetic characteristics.”
But while mealworms and other alternative protein sources like bacteria and algae might help supplant aquaculture’s dependence on wild-caught fish, not everyone is convinced aquaculture should be the future source of our seafood. “The system itself is flawed,” says Marianne Cufone, an environmental lawyer and executive director of the Recirculating Farms Coalition, a group that advocates for small-scale community-based food production. “What challenges are we causing in trying to ramp up industrial food production? I think there are just a lot of questions there that are not so easily answered.” Cufone is one of the advocates leading the opposition to a planned open-water fish farm in the Gulf of Mexico. In aquaculture terms, the proposed farm is small – just 20,000 Almaco jack fish in a net pen 113 kilometres south-west of Florida – but the decision to go ahead with it or not will have big implications for the future of aquaculture in the United States.
The US is a tiny player when it comes to aquaculture; in fact it imports 85 per cent of all its seafood. Oysters and clams make up the lion’s share of its small aquaculture industry, with salmon, mussels and shrimp lagging way behind. Up until now almost all of this aquaculture has taken place in state-controlled waters, within five kilometres of the coastline, but federal waters, which extend between five and 320 kilometres from the coastline, represent a hitherto-untapped source of open space that could be filled with fish farms. And it looks like the US could be opening up to open-ocean aquaculture in its waters. In August 2019 the US Environmental Protection Agency issued a draft permit for the Almaco jack farm in the Gulf of Mexico to Ocean Era, a Hawaii-based aquaculture firm that has already conducted two open-ocean trials in the waters near Hawaii.
In May 2020 the Trump administration signed an executive order pushing federal authorities to prioritise open-ocean aquaculture. Three months later the National Oceanic and Atmospheric Administration (NOAA) officially designated the Gulf of Mexico and waters off southern California as the country’s first ‘Aquaculture Opportunity Areas’, which are earmarked for between three and five commercial aquaculture farms. The main driver behind the Trump administration’s push for aquaculture was a desire to make the country more food-secure, but as critics of the move point out, America already exports about 84 per cent of its domestically caught fish, some of which eventually returns to the country as imports.Opponents to open-ocean aquaculture in the United States argue that big fish farms will damage coastal fishing communities and won’t help people who really need access to cheap, healthy sources of protein. “When it comes to food access, much of that fish doesn’t end up on the plates of those who need the food most,” says Niaz Dorry, coordinating director at the Northwest Atlantic Marine Alliance, a fisherpeople-led advocacy group. Instead of focusing on fish farms that produce only a handful of species, we should be eating a much wider range of fish that can be fished sustainably by local communities that depend upon the industry, she says.
In August 2020 the push for open-ocean agriculture in the US was dealt a blow when a court ruled that NOAA lacked the authority to designate Aquaculture Opportunity Areas, with the debate likely to continue on Capitol Hill. But for Cufone, the looming threat of fish farms is just another symptom of a country where people are too often disconnected from where their food originates – a problem that goes way beyond fishing.
“What I would love to see is a series of small, local farms producing food for their own communities,” says Cufone. In the Central City neighbourhood of New Orleans she’s built a small aquaponic farm fuelled mostly by solar power and rainwater, which farms catfish alongside greens, tomatoes, cucumbers and melons. In the past the farm has sold the fish to local restaurants, and bags of fruit and vegetables to local residents. “We live in a very low-income area and one of the primary focuses for the farm was to provide food for very low-income, low-resource residents,” she says. “There’s something to be said for community awareness, understanding how hard it is to grow food and understanding the real value of farms and farmers.”
If the world heeds the call for healthier, more sustainable diets, then the way we produce fish is set to become one of the defining issues of the future of food. From where we are now, two things are clear. First, the share of fish that are caught from the wild is likely to keep declining as the aquaculture industry continues to boom. Second, the aquaculture industry is in for a slow reckoning, as companies and governments grapple with the environmental impacts of farming fish. There are plenty of signs, however, that the industry is learning at least some of the lessons from the livestock industry and the environmental chaos it unleashed as it rapidly industrialised. Innovators like Goldman, Fitzsimmons and Hubert are already laying the foundations for a future where animal protein doesn’t need to come with such a high environmental cost.
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