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Vegetarian Fish Could Be the Biggest New Development in Sustainable Seafood

In attempts to curb overfishing, researchers have found that fish such as trout, yellowtail, walleye, and Atlantic salmon can survive, and even thrive, on vegetarian and fish-free diets.
Photo via Flickr user Jeff Jones

As the world's population grows, so does its demand for fish—the silvery, lean, delicious protein swimming beneath the waves. But, to the chagrin of every child who's ever spent hours staring at an unflinching bobber, we've become such ruthlessly efficient fishermen that we're depleting our oceans and throwing away millions of tons of accidental bycatch annually. Scientists warn of a global fish collapse by mid-century—after that, fish pulled straight from the oceans could be a thing of the past.


Fish farming may seem like a way to alleviate pressure on the world's oceans while meeting the global demand for fish, and experts currently estimate that fish farms will produce two-thirds of fish for consumption by 2030. But in addition to the best-known concerns about fish-farming, such as pollution and the spread of disease, there's another issue: what the fish are farms are getting fed.

READ: There's Still Time to Stop the Fish Apocalypse

Fish farms use meal that contains small wild fish called forage fish, such as sardines, anchovies, mackerel, and herring. These forage fish occupy a critical place in the ocean food web as plankton-eaters that are in turn eaten by larger predators like salmon and tuna, and their populations are already perilously low. Annually, we haul in 31.5 million tons of these forage fish, 90 percent of which are rendered into fishmeal and fish oil and fed to farmed fish like salmon and cod (as well as poultry and pigs).

To address what seems like a pretty obvious sustainability problem, scientists are now keen on developing a fish-free fish food: Fish in the future could go vegetarian.

A recent report from the Lenfest Forage Fish Task Force called for the amount of forage fish we are pulling from the ocean to be cut in half. "The basic idea is that [forage fish] are the 'Kobe beef' of the marine world—super energy-rich food that is super productive and widely available to a lot of predators that we care about," Tim Essington, a professor at the School of Aquatic & Fishery Sciences at the University of Washington, wrote to me in an email. Essington recently was the lead author of another study that found that fishing amplifies forage fish population collapse. "Vegetarian feed, if it could be used widely in aquaculture, would greatly relieve fishing pressure on forage fish," he wrote.


Rick Barrows, a research nutritionist at the United States Department of Agriculture, has been researching alternative diets for fish for the past 28 years. "Forage fish have always been an easy way for nutritionists to get what they need," Barrows says. Barrows' research involves breaking down the natural diet of fish to the nutrient level and reassembling a new diet from alternate ingredients that meet their existing nutritional needs. Fish, like many other animals, require about 40 different nutrients in their diet for optimal health. "I don't talk about fishmeal replacements anymore, because we can replace it. I talk about needs for high-quality proteins."

The USDA has found that eight supposedly carnivorous fish—including yellowtail, walleye, and Atlantic salmon—can survive, and even thrive, on vegetarian and fish-free diets. Substitutes for forage fish include insects, algae, and plant products, such as soy and pistachio meal. "We look at everything," Barrows says, including what not to include. Though he works a lot with soy, Barrows notes, "Soybean meal, for example, gives trout diarrhea, which isn't good in a recirculating tank."

READ: The World's Biggest Chefs Want You to Eat the Ocean's Smallest Fish

In 2009, Barrows was approached by Two X Sea, a sustainability-minded fish supplier based out of San Francisco, to produce a vegetarian feed for farmed rainbow trout. The feed he created with Two X Sea contains red algae, pistachio, flax, corn, and more. The trout, which cost more than your average farm-raised trout, is sold to restaurants and consumers alike in and around San Francisco, making Two X Sea the first commercial producer of fully vegetarian farmed fish.


Chef Laurence Jossel serves the vegetarian trout at his San Francisco restaurant, Nopa. As an ingredient-focused, sustainability- and locavore-minded chef, Jossel at first rebuffed the idea of serving a farmed fish. "The trout I've worked with in the past, if it's farm-raised trout, is just a terrible product. It's not fresh, it doesn't have any flavor, it doesn't smell very good," Jossel says. "We stopped using it years ago, it just wasn't any good." But when he learned about Two X Sea's process, he gave it a try.

"The fish is super clean," Jossel says. "It's sized nice. It doesn't come in smelling like fish." Nopa's menu now features the trout, which Jossel brines with beer, sugar, and salt and serves smoked.

Reworking fish diets is nothing new. "Even back in the 70s and 80s, we were looking for alternatives for fish meal," Barrows says. "Then, it was more price-driven versus availability. Now it's [about] availability and price."

Changing economies have made the situation more urgent. Due to increasing scarcity, the price of forage fish has gone up nearly four-fold since the turn of the new millennium, to roughly $2,000 a ton. Two X Sea's vegetarian fish food costs more than its competitors', but at scale, it could offer a viable economic alternative to forage fish, especially if the price of forage fish continues to rise.

"It's expensive, of course," Jossel says of Two X Sea's trout. "But you get what you pay for."


Barrows has hope that fish farmers can cut their reliance on forage fish. "I'm very optimistic, because in the last five years we've seen tremendous changes in commercial feed formulas," he says. The amount of forage fish in feed has been cut considerably. But there will be challenges. Barrows expresses concern that if farmers stopped using forage fish in feed, their price would drop and they would continue to go towards feeding poultry and swine at even higher volumes. Essington, however, notes that other meat industries have likewise developed alternate feeds as fishmeal prices have risen, and they may choose to stick with their new innovations.

For the individual producer, the choice of feed will largely remain an issue of economics. What may perhaps be seen as a sign of progress, though, is that it is becoming increasingly apparent to a greater number of people that if we hope to enjoy fish as a resource in the future, something has to change.

"Our oceans are in trouble. There are not going to be a lot of wild fish in the future, especially the way we are fishing," Jossel says. "So what's the answer? We have to create fish in a sustainable way. We don't feed them other fish."

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