Healthy Eating: Farmed vs. Wild Caught Fish

IWL_K_Carlino_headshotBy Kristin Carino, RD

We’re all familiar with large-scale agriculture and its effects on our health and the environment. Did you know that something similar is happening in our waters? Fish farming, or aquaculture, has been the fastest growing sector of animal food production in the world since 1970. The fish raised—in netted cages in coastal waters—currently provide almost one third of all seafood sold. Estimates are that half the fish consumed worldwide will be farm-raised by the year 2025.

Fish can either be one of the best foods for you or detrimental to your health, depending on where it is sourced. There is a world of difference between fish that is caught in the wild, farm-bred or farm-raised fish.

At first glance, fish farming may seem like a good idea, a way to ease the stress on overfished populations and help meet the food demands of the world population. But large-scale aquaculture also brings problems, especially antibiotic use. The most common farm-raised fish are salmon, tilapia, sea bass, catfish, and cod.

Farmed fish may contain high levels of contaminants like PCBs, and polybrominated diphenyl ether (PBDE). According to research published by the Environmental Working Group, PCBs found in farmed salmon (at levels 16 times higher than in wild salmon) are in levels high enough to pose an increased risk for cancer.

Antibiotics and other drugs and pesticides used in fish farming sift to the sea floor and seep into open waters. As with antibiotic use in feedlots, there’s serious concern that overuse can create drug-resistant strains of disease that can wipe out wild populations. Also, a synthetic dye called canthaxanthin is used to color farm salmon, which would otherwise be grey. Salmon in the wild absorb a carotenoid called astaxanthin from eating pink krill; this contributes to their naturally pink color. The synthetic dye has been shown to adversely affect sight when consumed in large quantities.

Sea lice, which thrive in fish farms, threaten large numbers of wild fish that migrate past the area. Fish farmers respond to sea lice by adding a pesticide to the fish feed.

Farmed fish are generally less nutritious than wild fish. While fish is good for you—low in saturated fat and high in protein, amino acids, and omega-3 fatty acids—there is a substantial difference between farmed fish and wild fish. According to FDA studies, farmed fish are fattier (cultivated catfish have nearly five times as much fat as wild, for example). Wild salmon were found to have a 20 percent higher protein content and a 20 percent lower fat content than farm-raised salmon. And farm-raised fish contain twice as much omega 6 fats than their wild counterparts. Omega-6 fatty acids, which are also found in dairy and most vegetable oils from corn to soybean to sunflower, have pro-inflammatory qualities and can result in increased risk of chronic disease, including heart disease, over time. Sardines and wild-caught salmon are excellent sources of healthy omega-3 fatty acids, as do flax seeds and walnuts.

And there are disadvantages to wild fish, too. Often imported from distances and more expensive to harvest, wild fish usually cost more than farmed fish. Many of the older, larger ocean fish are highest in toxins like mercury.

What’s Healthiest to Consume?

The decision to purchase wild over farm-fished isn’t easily made. What may matter most is how sustainably the fish you’re eyeing for dinner was raised and/or caught. Read signs and labels at the fish counter. Ask about the source of the fish. Visit the Blue Ocean Institute ( for their Guide to Ocean Friendly Seafood. And, look for the Marine Stewardship Council’s “Fish Forever” label, which assures that the fish is from a fishery that uses sustainable practices.

When purchasing wild seafood, choose products that have been caught using sustainable methods like hook and line fishing, trap fishing, and longlining, which have less environmental impact, rather than trawling.

To reduce your consumption of toxins in fish, avoid excessive intake of the longest-living, largest, carnivorous fish in the ocean, like salmon, tuna, swordfish, and shark. Alternatives with similar health benefits include trout, sardines, mackerel, and herring.
As with many things in life, the best advice to following a healthy diet is ‘all good things in moderation.’ To build a healthy diet that addresses your particular health and wellness needs, consult a registered dietician.

Kristin is a registered dietician and part of the Institute for Weight Loss at Raritan Bay Medical Center in Old Bridge, NJ. The Institute provides individualized medical and surgical solutions and support for individuals seeking weight loss, who have been unable to lose weight through conventional dieting, exercise or weight loss medication. To attend a seminar or make an appointment, call 1.855.TIME.4.ME.

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