Farmed Fish: To Buy or Not to Buy


If you’ve ever stood in front of the seafood counter at the grocery store, utterly confused on whether to buy wild or farmed fish and what the differences are, we hear you. We’ve been there, too! To help us better understand this issue, we’ve tapped Sophie Egan, author of How to Be a Conscious Eater: Making Food Choices That Are Good For You, Others, and the Planet to share an excerpt from her new book.

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Farmed Fish: Yay or Nay?

You can think of a typical fish farm much like a cattle feedlot: Too many creatures crammed into too little space and fed too much sub-optimal feed, making them too sick and fat. Tens of thousands of rapidly growing fish swarming amid net pens or ponds. Ergo, fish farmers relying on the usual Band-Aid solutions—antibiotics, pesticides, and other chemicals—which round out the CAFO (confined animal feeding operation) analogy by similarly contributing to antibiotic resistance and environmental degradation. But instead of in factory farms on land, it all transpires under water.

More reasons not to eat farmed fish

Fish out of water

It’s harder to maintain a hard border, so to speak, when you’re housing living things in a body of water. Imagine large cages made of netting, floating offshore. Inevitably, fish escape, at least in the case of farmed salmon, which is a particularly problematic type of fish farming. This can result in the spread of disease as well as fish acting as invasive species in these waters where they don’t belong. They can even mate with wild fish, which can mess with the genetics of the wild population. 

Less healthy fish

When fish are confined, they’re less active. The result is fish who are fatter than their wild cousins, who get tons of exercise and live off small fish and krill (little crustaceans). For us, this means farmed salmon develop up to three times the saturated fat of wild salmon (much like the comparison for grass-fed beef). This high saturated fat content is caused by what the farmed salmon are fed, which is a face-scrunching blend of pellets made from fish oil and fish meal (derived from larger fish), soy and wheat, and sundry by-products of slaughtered farm animals. Excuse me, but what’s a fish doing eating a cow!? Talk about Frankenfood. 


Unfortunately, methylmercury isn’t the only toxic chemical that finds its way into our fish supply. After years of agricultural and industrial uses, chemicals including poly­chlorinated biphenyls, or PCBs, were banned decades ago because of suspected ties to cancer and skin and liver harm. But their waste streams have left residual contamination in waters that fish inhabit. Though reports vary, several studies have found that PCB levels are much higher in farm-raised salmon, which is likely caused by the way PCBs concentrate in oils and fat, which fish meal is high in. Consuming high amounts poses risks during pregnancy and early infancy, and the higher up the food chain a fish is, and the more a fish eats lots of other fish, the more PCBs it’s likely to have. If this sounds familiar, it’s the same principle of bioaccumulation that puts predator fish at the top of the no-no list for mercury. Unfortunately, fattier fish have more PCBs, and those are the ones at the top of the yes-yes list for omega-3s. (It’s exhausting, I know. Believe me!)

Pink dye

Krill are also what give wild salmon its enticing bright pink color. To mimic that color in farmed salmon, artificial coloring is added to feed pellets, which the fish flesh absorbs. Salmon farmers use the dye to get their product to sell, since consumer research shows that almost no one is psyched about eating a fish fillet that’s gray. The health effects of the dye are not yet understood, but in the interest of transparency, many consumers want to know.

Depleting wild fish stocks for feed

Producing fish feed is extremely inefficient. It takes more than 15 pounds of wild fish to produce one pound of farmed tuna. This practice ravages stocks of certain “forage fish” (anchovies, herring, menhaden) to make fish meal and fish oil to feed the fish whose wild stocks you’re supposedly offsetting by enhancing the total supply. Not a great trade. 

Environmental impact

Spillage or intentional discharge of the toxic chemicals used for the aforementioned crowded net pens or ponds, not to mention waste, can damage surrounding waters and the life within them. 

Still, before we exile the food category entirely, here’s an important caveat…

Not all food that comes from aquaculture (the business of fish farming) is the same. 

Bivalves—mussels, clams, scallops, and oysters—are farmed more responsibly. They’re not carnivores, so they don’t require wild fish. Moreover, because shellfish are filter feeders, water quality is often improved as a result of their taking up residence. 

Farmed fish systems that use recirculated, treated water for fish in tanks (on land) generally don’t negatively affect wild fish and their habitats. Examples of species routinely raised in this way in the United States are Arctic char, catfish, cobia, tilapia, and trout, according to Seafood Watch.

In judging a given food choice, you always have to ask, “As opposed to what?” If you’re considering not eating farmed fish because you’re worried about the dye or other environmental issues, but then you go and eat a burger instead, that’s not exactly a smart swap. 

What to do 

In the case of salmon, eat wild only, and either consider it a special-occasion treat, since it costs a pretty penny when fresh, or look for affordable ways to enjoy it more regularly, from frozen to canned. Skip the farmed stuff. 

If you do pick farmed salmon, check Seafood Watch for not only the best method and type of salmon but the country of origin; according to Oceana, Chile’s salmon farms use an enormous quantity of antibiotics, whereas those in Norway use hardly any.

Eat the feed. Small fish like anchovies and herring are used to feed farmed fish like tuna. Instead, eat those little guys. As with eating plant-based foods in place of animals they’ve been fed to, eating the feed signals to the market that “feed” is also valuable human food. 

For farmed fish and seafood, again, go lower on the food chain (think shellfish). The carbon footprint of mussels, for example, is thirty times less than that of beef.

Opt for fish species that do well onshore, such as Arctic char, catfish, cobia, tilapia, and trout. 

book cover

Excerpted from How To Be A Conscious Eater: Making Food Choices That Are Good for You, Others, and the Planet by Sophie Egan. Illustrations by Iris Gottlieb. Workman Publishing ©2020.