Fish and shellfish are full of healthy fats, vitamins, and minerals. Great for our physical and cognitive wellbeing, they’re a solid addition to a nutritious diet.1
That said, not all seafood is created equal. This post will outline the differences between farm-raised and wild-caught fish, including their impact on our health and the environment.
What are the differences between farm-raised and wild-caught fish? Fishermen catch wild fish and shellfish in lakes, rivers, oceans, and other bodies of water. These fish eat a natural diet.
Farmed fish are bred for human consumption through a process called aquaculture. This means they live outside their natural environment and are generally given processed feed.2
Specifically, farmed fish are placed in pens submerged in ponds, lakes, or even saltwater.1 Some pens are filled with water and kept on land.
While this might not sound ideal, fish farming isn’t inherently bad. Sustainable farming practices have become more common than ever, as the World Bank estimates that almost two-thirds of seafood will be farm-raised by 2030. In Norway and Canada, for instance, most farmed salmon are cultivated through an eco-friendly recirculating aquaculture system.3
Here are some other items to consider:
Nutrition: Which fish variety is better for your health?Fish have been shown in clinical studies to display anti-inflammatory properties, not to mention being rich in heart-healthy omega-3 fatty acids.3 The overall quality of seafood, however, depends largely on what fish eat. Wild fish consume a natural diet lower in saturated fats.5
What does this mean? Let’s focus on salmon for a moment. In addition to being higher in saturated fat than wild salmon, farmed salmon contains more omega-3s and 46% more calories. The wild-caught stuff, however, is richer in minerals like potassium, zinc, and iron.4
Consider the following when evaluating both fish varieties for your health:
Most people consume too much omega-6, which may cause inflammation and other symptoms. And farm-raised salmon specifically—despite containing higher quantities of omega-3—has a significantly higher omega-3-to-omega-6 ratio.4 The ratio is still good enough, but it isn’t quite at the level you would find in wild seafood.
Of course, the trace metals found in fish aren’t limited to mercury. Farmed salmon contains higher arsenic levels, while wild salmon contains more cobalt, copper, and cadmium.7 Fortunately, levels of trace metals in both wild and farmed fish are usually so low they’re unlikely to harm the average person.4
Some studies indicate that farm-raised fish have higher levels of contaminants.4 Furthermore, seafood raised via aquaculture may have a higher rate of disease because of some of the farming practices and conditions.5
For example, approximately 530 grams of antibiotics were used per ton of harvested Chilean salmon in 2016. (In contrast, Norway used just 1 gram of antibiotics per ton of harvested salmon in 2008.)4As such, it’s essential that you understand where your fish is from before consumption.
Sustainability: Which fish variety is better for the environment?Fish accounts for 17% of our global protein intake.8 For this reason, we can’t rely on wild-caught fish alone. There just isn’t enough wild seafood to keep up with the growing demand.
Based on our current trajectory, there’s a global need for another 80 million tons of farmed fish per year by 2050.8 Yet aquaculture may be detrimental to the environment too. Use of antibiotics can cause damage to the environment and adversely affect human health as well.4
Moreover, when lots of fish are crammed together in a small space like a pen, they create a ton of waste that can pollute rivers, lakes, and oceans.8
And the environmental consequences of fish farming doesn’t end there, either. Some fish farms are disease-ridden, which can be toxic to the environment; in Indonesia, shrimp farming specifically has contributed to the decline of the nation’s mangrove forests.8
Since we don’t want to deplete what’s left of our wild fish resources, where does that leave us?
Fortunately, some experts say that feeding farmed fish a higher-quality diet free from antibiotics can help address some of the problems described above. Similarly, as fish farmers gain efficiency, governments will be more likely to offer incentives for the adoption of sustainable practices.8 Ideally, the environment will become an even greater focus for everyone in the near future.
The verdict on wild-caught vs. farm-raised fishWhile wild seafood is generally healthier than farmed fish and shellfish, sustainable methods make many farm-raised options completely viable. Both wild-caught and farm-raised fish varieties offer plenty of protein, the omega-3 Docosahexaenoic acid (DHA), and other essential nutrients.4
To make sure you’re eating top-quality seafood, be sure to look into where your seafood is from, and opt to eat local, low-mercury varieties when possible.
For more information on nutrition and general wellness topics, please visit the Metagenics blog.