Fish Nutrition

Before we launch into comparing farmed vs. wild fish, let’s get one thing straight – any fish is better than none! If you’re eating fish regularly, give yourself a pat on the back. Fish provides you with lean protein and healthy omega-3s to help with reducing cardiovascular disease, inflammation, blood pressure, and improving brain performance. In fact, the Academy of Nutrition and Dietetics as well as the American Heart Association and Institute of Medicine recommend eating at least two 6-ounce servings per week.

So it’s widely recognized that fish is good for us, but some wonder about the nutrition differences and safety of farmed vs. wild fish. If you’re curious about the questions concerning fish nutrition or contaminants, read on.

Issue: Nutrition Content of Fish

Many individuals think wild fish has more nutritional value because it is more “natural,” but is this true? The differences aren’t as great as you might expect. For example, farmed and wild Rainbow trout are nearly identical in calories, protein, and most nutrients. There are some small differences – farmed have more vitamin A and selenium, while wild have a bit more calcium and iron.

Farmed fish are often given a diet they would not have access to in the wild, such as corn, or soy-based feeds. They may be fed supplements to achieve nutrient or color profiles as well. Today’s farmed Atlantic salmon contain more omega-3 fats than wild, largely because they are raised to meet an omega-3 content goal. In fact, most farmed fish have somewhat higher omega-3 contents than wild.

Issue: Heavy Metals and PCBs

A lot of the undesirable contaminants in fish, such as mercury or other heavy metals, build up over time and are thus found in fish that have longer lives. In this case, farmed vs. wild is not really the issue – it’s the age of the fish. The fish with highest mercury content concerns are king mackerel, swordfish, shark, and tuna. It is recommended that women who are pregnant avoid or limit consumption of those four fish. Some low-level fish include salmon, catfish, and tilapia. In general, farmed fish may be more protected from heavy metals than wild fish, simply because they are in a contained area.

PCBs, potentially carcinogenic chemicals, are present in both wild and farmed fish. The levels may sometimes be slightly higher in farmed, but the levels are still less than 2% of the amount that would be considered dangerous.

Issue: Antibiotics, Hormones, and GMOs

Worried about fish being filled with antibiotics and hormones? Farmed fish may contain antibiotics and hormones but, they are only utilized to maintain the health of the fish to ensure diseases are kept under control. The antibiotics and hormones in fish are NOT to increase fish size or growth rate. U.S. regulations prohibit the use of hormones or antibiotics to promote growth in farmed fish. However, this restriction may not be in place in fish farms of other countries. If this concerns you, make sure your fish are raised in the U.S., or research the methods used by the brand you buy from overseas.

In the U.S., farm raised fish are NOT genetically modified. The only ones available are the glow-in-the dark varieties sold for fish tanks (which hopefully aren’t the ones on your menu).

Issue: Environmental Sustainability

Environmental concerns apply to both wild and farmed fish. If not done properly, wild-caught fish may be harvested using practices that do a lot of damage to the ecosystem. If fish farming is not done properly, it can pollute the water and threaten local flora and fauna. The case for the environment is like purchasing food of any other kind – ensuring you have a reputable source.

Here in the U.S., the National Oceanic and Atmospheric Administration regulates wild-catch fishing, setting, and enforcing standards that protect the marine environment and fish populations. Fish farming operations in the U.S. are also strictly regulated. These regulations are often not in place in other parts of the world.

The Verdict: Weigh Your Options and Stay Informed

There are a lot of factors to weigh: nutrition, safety, sustainability, and cost. The decision should include personal values, the type of fish being bought, where it was raised, AND how it was raised and processed.

This may seem like a daunting decision, but don’t worry! There are tools that can help you:

  • (the Monterey Bay Aquarium), OR the Seafoodwatch app
    • Search by type of fish, learn the issues, and get recommendations for best choices and alternatives
    • Stay on top of industry practices and environmental issues around the globe
    • Printable card for your wallet available
  •  Marine Stewardship Council (MSC)
    • Navigate healthier fisheries
    • Navigate more sustainable fisheries

– By Morgan McManimon-Myers, BS, RDN

Sources: Academy of Nutrition and Dietetics; American Heart Association and Institute of Medicine; Seafood Watch Program; (Nutrition Professional written)

For more information on the benefits and nutrition of fish, check out this article: Farmed vs. Wild Salmon!