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menu Big Fish: The Aquacultural Revolution
workers feed fish at fish farm
With nearly 90 percent of wild fish stocks already fully exploited, over exploited, or depleted, feeding wild fish to farmed fish is unsustainable. The aquaculture industry is on the hunt for alternatives. Photo by Mark Conlin/Alamy Stock Photo

Taking the Fish Out of Fish Feed

Feeding wild fish to farmed fish is threatening marine ecosystems. Researchers and entrepreneurs believe they’ve found solutions.

Authored by

by Brian Payton

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The air inside the greenhouse is abuzz with flying insects. They rise and fall above endless trays teeming with their larvae. Here at Enterra Feed Corporation’s research facility near Vancouver, British Columbia, they don’t grow flowers or vegetables. Instead, they farm soft-bodied, legless consumers of decomposing matter. My guide, Andrew Vickerson, prefers that you not call them maggots.

Call them what you will, they appear to be little more than a mouth and trailing rolls of fat. Once past the larval (or grub) stage, during which they can grow as long as a paper clip, they metamorphose into winged adults. With their bulbous eyes, wasplike antennae, and loud buzz, the adults seem intimidating, but, lacking mouths, they are unable to bite or eat. They live only to mate and lay eggs for the next generation. Their entire life span is about 35 days. They are best eaten while still young.

Vickerson waves the air in front of his face, chasing away escapees of the nearby breeding pens. He was the first employee hired by Enterra back in 2009 when he was 25. Environmentalist David Suzuki and Enterra CEO Brad Marchant (recently retired) founded the company on a hunch. Insects play an important role in the diet of fish in the wild, they reasoned. Why not of farmed fish? While other insects were considered early on, all the research kept pointing back to a single species: Hermetia illucens, the black soldier fly.

black soldier fly

As adults, black soldier flies live only to mate and lay eggs for the next generation. Photo courtesy of Enterra Feed Corporation

As Vickerson has learned, black soldier flies can be farmed extremely efficiently. Enterra pioneered and patented some of these techniques. But at the heart of their operation is a very low-maintenance livestock. You don’t have to hunt, fish, or grow anything to feed them. They don’t require fresh water. As larvae, they’re happy eating all manner of food waste that would have ordinarily gone to compost or the dump. Black soldier fly grubs, Vickerson explains, can recycle these nutrients back into the food chain because, unlike many other insects, they can consume a wide variety of foods. In the larval stage, they are packed with protein and are high in fat, including the omega fatty acids highly prized by the aquaculture industry and consumers alike. Native to the Americas, black soldier flies now range throughout the warmer parts of the world, although they do not naturally occur in Canada.

In 2014, Enterra opened this football field–sized facility and began producing black soldier fly grubs (dried, whole), plus protein powder and omega-rich fatty oil made from ground-up grubs for aquaculture. The protein powder and oil have caught the eye of the industry.

“We started the company to address two major global problems,” Vickerson explains. “One is the need to feed a lot more people. By 2050, we need to make 70 percent more food. At the same time, we have limited resources and 30 to 40 percent of the food we produce is wasted.” The bulk of this is “pre-consumer” food waste, Vickerson explains, food that either goes bad between the farm and the market or is a byproduct of food production. Enterra turns that waste into fat and protein that can be sold to fish-feed manufacturers for use in the aquaculture industry as a replacement for fish meal, which typically consists of ground-up fish and fish oil.

Aquaculture, the world’s fastest growing food production sector, is facing an existential crisis. Our appetite for seafood continues to grow, but with nearly 90 percent of wild fish stocks already fully exploited, over exploited, or depleted as of 2018, feeding wildlife to livestock is an unsustainable business model. Every day, the aquaculture industry has to feed billions of farmed fish. Prevented from hunting or foraging for themselves, they are left to watch for the hail of nutrients tossed from above.

One of the main sources of those nutrients is wild “forage” fish stocks, which are made into fish meal. One source is anchoveta, a small, oily fish that spawns off the coast of Chile and Peru twice a year. The upwelling, nutrient-rich Humboldt Current can still result in schools so large they can be tracked by satellite. Birds, marine mammals, and larger fish all compete for the bounty. One of nature’s most spectacular events, it is also the most heavily exploited fishery in the world. Remarkably, only two percent of the total catch goes directly to feeding people; 98 percent is ground up into fish meal and fish oil and sold to the aquaculture industry in countries like China, Japan, and Norway.

Peruvian anchoveta

The wild Peruvian anchoveta is the most heavily fished species in the world, and nearly all of the catch becomes fish meal and oil for aquaculture. Photo by Mark Bowler/Alamy Stock Photo

Every year, 20 million tonnes of forage fish—anchoveta, but also herring, sardines, and mackerel—are removed from the world’s oceans. Seventy percent goes to feeding farmed fish; most of the rest is fed to chickens and pigs.

The price of fish meal has risen as the industry grows and competition heats up for what remains. Can alternative sources of nutrition be found for farmed fish that are both economically and environmentally sustainable? Scientists, corporations, and NGOs are scrambling to find the answer. Some are looking further down the seafood chain at algae; some are looking beyond the sea to terrestrial crops. Others, like Vickerson, are eyeing the endless supply of spoiled produce that never reaches market. Whatever the solution, researchers say we need to find it fast. Nothing less than the health of the world’s oceans—and our own food security—depends on it.

In the meantime, the aquaculture industry has been getting used to getting by with less. Nearly three tonnes of forage fish went into producing one tonne of salmon in 1997. By 2017, forage fish made up only around 25 percent of a farmed salmon’s diet (down from 70 percent in the 1980s). The Food and Agriculture Organization of the United Nations (FAO) estimates that insects could replace anywhere from 25 to 100 percent of the remaining fish meal in the diets of farmed fish with no adverse effects. That’s where the maggots come in.


The urgent beep, beep of backing trucks can be heard in the delivery bay as drivers tip their otherwise worthless cargo. The seasonal menu includes a changing array of wilted lettuce, soft cucumbers, rotten tomatoes, stale bread, and moldy berries arriving from local greenhouses, farms, and bakeries.

We tour different sections of the facility, where countless trays and a waist-high conveyor crawls with wriggling grubs. Millions of them fatten up by gobbling a smoothie-like slurry made from whatever comes off the trucks. Only one percent will be allowed to live beyond the two-week larval stage. Those lucky few are kept to mate and lay eggs for the next generation. The remaining 99 percent gorge themselves and then ride the conveyor toward the light—in this case, a large dryer where they are roasted alive.

Black soldier fly larvae

Black soldier fly larvae, fattened on food waste, are a promising alternative feed for farmed fish. Photo courtesy of Enterra Feed Corporation

“We don’t have any arable land requirements,” Vickerson explains. He also claims this operation doesn’t create any methane. “And we’re able to produce more nutrients per square foot than any other farming system, because it’s a vertically stacked system.”

Black soldier flies also offer an immunity boost. Evolved to grow in decomposing matter under crowded conditions, they can withstand some pretty nasty pathogens. As a result, they’ve developed robust immune systems and don’t require penicillin or other pharmaceuticals like other livestock. Researchers are studying whether they pass on some of that immunity as prebiotics when they themselves are consumed—an added benefit not found in fish meal.

Researchers at Fisheries and Oceans Canada conducted a study in which a captive group of Arctic char was fed a diet that included 20 percent black soldier fly grubs while a control group had none. They measured growth rate, feed efficiency (weight gained divided by the amount of feed ingested), and survival rates for the first six months in the lives of the fish. While there was no difference in growth rate or feed efficiency between the groups, the survival rate among those fed black soldier fly grubs was 28 percent higher.

“It’s significant,” Vickerson says. “Something challenged the fish, and the insects they ate helped them overcome that challenge. For fish farmers, it’s like a built-in insurance policy.”

He also points to the other benefits of feeding grubs instead of fish meal to farmed fish—like being able to tell end consumers that the fish they eat has a smaller environmental footprint, that it didn’t involve the consumption of wild fish stocks, and that its nutrients were upcycled from otherwise wasted food production. All of which, he says, adds value.

A worker throws feed pellets into a fish farm pen

A worker throws feed pellets into a fish farm pen. Photo by Brian Atkinson/Alamy Stock Photo

Five years ago, regulatory approval for feeding Enterra’s insect products to food animals was the biggest obstacle between the company and the fish-feed market, but not anymore. Enterra has made progress with US and Canadian regulators, Vickerson says, and received approval to export to the European Union in early 2020. In the meantime, investors keep the conveyors rolling.

Along that lengthy regulatory path, Enterra discovered that its dried whole grubs are also well suited to the backyard poultry market. And chickens aren’t the only birds that love grubs. “Three to four billion dollars a year is spent on wild bird feed in the US,” Vickerson explains. “It’s a huge industry—the second most common hobby after gardening.” The global pet food industry, worth over US $35-billion in 2018, is also taking note. Vickerson says cats and dogs like black soldier fly oil and protein, too. In addition to pursuing these markets, Enterra collects the grubs’ dung—which falls like black dust below their trays—and sells it to local farmers as high-quality fertilizer.

The time has come to follow the conveyor to the end of the line. Vickerson’s schedule is packed these days because he’s busy overseeing the opening of Enterra’s new CAN $30-million production facility near Calgary, Alberta. At nearly 17,000 square meters, that facility (which opened in February 2020) is bigger than three football fields and can house billions of grubs at any one time.

soldier fly larvae products

Enterra Feed Corporation produces dried whole grubs, protein powder, and omega-rich fatty oil from black soldier fly larvae at their Canadian facility. Photo courtesy of Enterra Feed Corporation

Beyond regulatory approval, what’s preventing aquaculture from wholesale adoption of black soldier fly? It’s not price, Vickerson says, it’s volume. Large, international fish-feed mills require a steady, reliable production of 3,000 to 4,000 tonnes of product per year. The entire output of Enterra’s new, larger facility will barely meet the production needs of a single fish-feed mill. To truly serve the global industry, Enterra will have to grow exponentially.

“We’re planning another five to 10 facilities over the next five years,” Vickerson says, “depending on market uptake.” Marion, Ohio, is next on the roster.

By 2030, two-thirds of the fish we eat will likely come from aquaculture. In the rush to meet the growing demand for fish feed, Enterra is not alone. Other companies are working to bring black soldier fly grubs, other insect species, and various innovative sources of feed to market. But for at least one group of concerned researchers and NGOs, the future can’t come fast enough. They’re hoping to accelerate the process with a good old-fashioned contest.


Kevin Fitzsimmons is determined to disrupt the status quo. You can hear it in his voice. He’s in Myanmar, leading a three-year sustainable aquaculture program, funded by the European Union. In his life back home, he’s a professor in the department of environmental science at the University of Arizona, a research scientist, and a judge of the F3 (Fish-Free Feed) Challenge, a collaborative effort between NGOs, universities, researchers, and private partnerships. He’s all too happy to get up early and talk fish feed across nine time zones.

“You know,” Fitzsimmons says, “I’m one of the people who got into aquaculture from the marine ecology, marine biology side of things. I think probably the vast majority of old-timers like myself got into it saying, Jeez, we’ve got to stop raping and pillaging the ocean and we can’t keep hunting and gathering wild seafood. We’ve got to domesticate these things and do it more sustainably.”

Fitzsimmons, who is also a former president of the World Aquaculture Society, has a unique global perspective on the industry. He believes sustainability lies in replacing the wild fish in fish meal and fish oil so forage fish can be left in the oceans for the seabirds, dolphins, and larger fish that depend on them.

Research scientist Kevin Fitzsimmons

Research scientist Kevin Fitzsimmons, who is also a judge for the F3 (Fish-Free Feed) Challenge, believes sustainability lies in replacing the wild fish in aquaculture feed. Photo courtesy of Kevin Fitzsimmons

One of the things that drives consumer interest in eating fish, particularly salmon, is omega-3 fatty acids. But consumers are largely unaware of the fact that the amount of omega-3s in farmed salmon has declined significantly over the past 10 years. This decline tracks with the decrease of fish meal in fish food and the remaining supply of fish meal being spread thinner as the industry grows. Without alternative sources of fish-free omega-3s to feed the aquaculture industry, the world’s oceans will not keep up with the demand for forage fish. This could result in major supply chain disruptions, Fitzsimmons says, as well as ecological collapse. Some fisheries have already collapsed.

Probably the most famous is the sardine industry in California, which collapsed back in the 1950s and 1960s because of overfishing, Fitzsimmons says. “We are seeing the same phenomenon going on in many of these forage fisheries around the world.”

The anchoveta fishery off the coast of Chile and Peru is actually one of the few being managed in a more sustainable way, Fitzsimmons says. Half of the world’s forage fisheries are desperately trying to establish catch limits while the other half are not. The ones without limits are being severely overfished—and the problem is getting worse. In Myanmar, for example, which has more coastline than California, Oregon, and Washington State combined, fisheries (including forage fisheries) have collapsed by 70 to 90 percent. That collapse is having ripple effects throughout the marine ecosystem. And that’s just the environmental side. Fitzsimmons also points to the labor abuses in forage fisheries throughout Southeast Asia.

Enter the F3 Challenge. The first challenge, in 2015, asked contestants to create a fish-free fish feed for the aquaculture industry. Guangdong Evergreen Feed Industry Company, a Chinese feed company, won over US $200,000 for their protein mix comprising soybean, rapeseed, and peanut meal. In 2019, the second competition, which called for the creation of a fish-free fish oil substitute, saw four teams compete with various formulations for a $200,000 prize. Veramaris, a joint venture between two Dutch companies, DSM and Evonik, won with their oil made from algae—which has twice the omega-3s of fish oil. Combined, the four contestants sold approximately 850,000 kilograms of fish-free oil, saving the equivalent of over two billion wild fish, the “largest amount of fish ever saved through a contest,” the organizers claim. For whatever reason, black soldier fly—which is further along in development—was not among the formulations entered in the competition.

prize being awarded at the F3 competition

Yuchi Chen (right), from Guangdong Evergreen Feed Industry Company, accepts the inaugural F3 Challenge prize from Fitzsimmons (center) for developing a fish-free protein mix from soybean, rapeseed, and peanut meal. Photo courtesy of F3 Challenge

“Black soldier fly is one of these big targets,” Fitzsimmons explains. “I mean, there must be 50 different companies around the world that are moving very, very rapidly into commercial production in scaling up black soldier fly.” Other companies are looking at different grubs (such as housefly, mealworm, and silkworm), beetles, crickets, and other insects. “Ecologically, I think this is fantastic,” Fitzsimmons says. He remains agnostic about what the solutions might be, as long as they’re sustainable and become available quickly.

Fitzsimmons points to Norway, which has the world’s largest salmon farming industry. Over the last two or three years, 27 percent of Norwegian producers have switched from conventional fish oil to algae-based oils, where forage fish get their omega-3s from in the first place. Getting an industry that large to change that fast is significant, Fitzsimmons says. And he suspects it’s just the start. “We see a confluence of economics, environmental interest, sustainability, interest from consumers, and economies of scale as the companies rapidly increase their production.”

Algae oil, insect meal, soy, camelina (an oilseed crop), and hydrolyzed feather meal from the poultry industry are all going to be more sustainable than continuing to remove forage fish from the environment, Fitzsimmons explains, and they could all play a part, but there’s no silver bullet out there. “There’s no one perfect algae oil that’s going to replace fish, and there’s not any single protein source that’s going to replace fish meal.” He suspects solutions will come from multiple sources.

Consider the vegan diet, Fitzsimmons says. If people are used to eating steak, they aren’t going to find a single plant that will replace steak’s nutritional makeup. In order to achieve the proper nutritional balance, they have to consume a variety of things. Farmed fish do not require fish meal or fish oil—they require the nutrients those ingredients happen to contain. As long as they get—and can process—the proteins, amino acids, fats, vitamins, and minerals they need to thrive, it doesn’t really matter where they come from.

“We don’t have any vested interest in whether it’s insect protein or GMO soy or camelina—whether it’s a Cargill product or a little backyard startup,” Fitzsimmons says. The contest is about letting innovators compete in a free market and getting the word out to the general public. He claims the contest has focused more media attention on the problem than “1,000 or even 10,000 scientific journal papers.”

Encouraged by the success of their first two competitions, the F3 Challenge team has cooked up a new contest, the F3 Challenge–Carnivore Edition, which calls for participants to create a fish-free feed specifically for shrimp, salmon, or other carnivorous species. That contest, with US $210,000 in total prize money, was slated to run through September 2021, but deadlines are being extended because of the COVID-19 pandemic disruption.

Farmed carnivores, like Atlantic salmon, have a large environmental footprint compared to other aquaculture species—in part, because their feed contains fish meal and oil from wild forage fish. Video by BlackBoxGuild/Pond5

Farmed carnivores have a larger environmental footprint than omnivorous species, such as tilapia, carp, and catfish, and much more so than bivalves like oysters, mussels, and clams. Why focus on predator species when groups like the Monterey Bay Aquarium Seafood Watch program, the Aquaculture Stewardship Council, and the FAO all encourage consumers to eat further down the food chain? Because people want these species and are familiar with them, and farmed carnivores are the industry’s biggest consumers of forage fish, Fitzsimmons says. “And if the market demand is there, let’s feed it as sustainably as we possibly can.”

But the authors of at least one of those 10,000 overlooked scientific journal papers Fitzsimmons mentions call for a different approach. They believe the answer lies not in serving, but shifting market demand. And perhaps foregoing the need for fish feed altogether.

In 2017, Jennifer Jacquet, Jeff Sebo, and Max Elder published “Seafood in the Future: Bivalves Are Better” in the journal Solutions. Lead author Jacquet is a Pew Marine Conservation Fellow and an assistant professor of environmental studies at New York University and works on issues related to overfishing and aquaculture. In their report, the authors found that the net contribution to the world’s food security through aquaculture—often used as justification for continued growth—seems to be “greatly exaggerated.” For example, farmed salmon is sold to food-secure markets, while the forage fish used to produce them—like anchoveta—are removed from potential human consumption in markets that are less food secure.

“We are currently witnessing the fastest and most poorly thought out expansion of domesticated animals ever to occur—the expanding domestication of aquatic animals,” Jacquet and her fellow authors declare. If done correctly, aquaculture could provide sustenance for our growing population as well as reduce overfishing, they say. “But if we want to avoid repeating the same mistakes, we need to make changes now, including changing our diets generally to include more plants and fewer animals.”

Based on the criteria of environmental impacts, food security, and animal welfare, they conclude, the ideal species to farm through aquaculture would be species of aquatic plants (hello, seaweed and algae). But assuming we insist on continuing to farm aquatic animals, “then the answer becomes species that are as plantlike as possible.”

Bivalves are non-migratory invertebrates, not migratory vertebrates like salmon. They are highly nutritious, do not require people to feed them, and (in some cases) even improve the environment around them. Jacquet and her fellow authors argue that this makes them the most environmentally sound choice and the least worrying when it comes to animal welfare—an issue that is mostly missing from the aquaculture discussion. There is an overwhelming public consensus that battery cages for chickens are unacceptable, for example. Why has intensive farming of migratory salmon escaped this kind of scrutiny?

mussel farm underwater

Mussel larvae settle onto ropes in farming operations, where the stationary bivalves grow and filter food from the water column. Photo by Louise Murray/Alamy Stock Photo

Jacquet and her coauthors agree with Fitzsimmons that forage fish should be left in the ocean for the marine life that depends on them, but they come to a different conclusion on how the aquaculture industry should proceed. For more than 35 years, they claim, scientists have been calling on the industry to farm species lower on the food web that require little to no feed. “Bivalves accounted for almost half of global aquaculture in the 1980s, but due to the explosion in finfish farming now account for only around 30 percent. This is precisely the wrong trend if we want animal aquaculture to lead to a more food secure, sustainable, and humane future,” they write.

The answer to aquaculture’s problems, they conclude, may lie in not simply replacing forage fish in fish meal and fish oil with novel ingredients like black soldier fly grubs, but in replacing farmed fish with farmed seaweed, or farmed scallops, clams, and oysters.


Back at Enterra’s vertical farm, the aroma is rich and earthy. Product is rolling off the conveyor in a steady stream. Black soldier fly grubs pass through the dryer and then cascade into open bins. The ones piling up below look much the same as they did before reaching the dryer, only now they no longer squirm.

The aquaculture industry is based on consumption and growth, not conservation. The onus to choose ethically and sustainably produced food falls on consumers. While Kevin Fitzsimmons believes we need to change what we feed farmed fish so we can continue to eat them, and Jennifer Jacquet and her coauthors suggest we grow and eat aquatic plants or bivalves, the FAO has been making the case for another food source altogether—one that does an end run around the entire seafood industry. For reasons of health, sustainability, and conservation—it recommends we eat insects.

Insects have probably always been a part of the human diet. Although eating them has fallen out of favor in the West, perhaps due in part to the fact that they were seen as destroyers of crops, it wasn’t always this way. The Greeks once relished their bugs. Aristotle, the 4th-century Greek philosopher and scientist, loved cicada nymphs. Roman scholar Pliny the Elder once wrote of the aristocracy’s taste for beetle larvae that had been raised on flour and wine. The Old Testament endorses the consumption of locusts, beetles, and grasshoppers. Around the world today, insects still appear on the menu in Asia, Africa, and Latin America.

Insects provide high-quality protein and nutrients comparable to meat and fish, and in the case of black soldier fly grubs, omega fatty acids. Although Andrew Vickerson says there is growing interest in eating insects, and that cricket flour can be purchased in many grocery stores today, he isn’t predicting a huge demand for black soldier fly grubs among North American consumers anytime soon. For now, at least, he’s focused on helping feed the aquaculture industry.

I take up a handful of still-warm grubs, fresh from the dryer, and finger through identical options. Vickerson joins me as I pop one into my mouth. Not gelatinous or gooey, not too dry or crunchy. Substantial. Rich and oily. Hints of roasted peanut with sunflower seed overtones.

Read the next story in our special editorial package on aquaculture: “Hold the Salt: The Promise of Little Fresh Fishes

Big Fish

The Aquacultural Revolution