Some studies suggest that people who eat fish live longer and enjoy healthier lives, with a lower risk of chronic diseases that affect much of the Western world. For instance, the ongoing Adventist Health Study has so far found that vegetarians outlive omnivores, vegans outlive vegetarians, and pescatarians (people who avoid all animal products except for fish) appear to have the longest life expectancy of all.
Meanwhile, in a 2019 review of 44 studies published in the highly specialized medical journal PLEFA (Prostaglandins, Leukotrienes and Essential Fatty Acids isn’t what most people would call light reading), researchers concluded that children of mothers who ate seafood weekly had significantly higher verbal IQ scores. The review also concluded that children who ate seafood had better school grades and higher IQ scores than their peers who ate no fish, by an average of 7.7 points.
Why are we seeing these benefits? Is it because fish is high in the long-chain omega-3 fatty acids, EPA and DHA, and these are beneficial for brain and cardiovascular health? Is it because fish-eaters are generally eating less red meat, or less processed foods, and these are the real culprits in harming cognitive development? Do fish-eaters tend to get more exercise? Are they less likely to smoke? Do they generally live healthier lifestyles?
Research is ongoing, and the data isn’t necessarily conclusive. However, there is substantial evidence that, for most people, at least compared with the Standard American Diet, fish consumption may be linked to positive health outcomes.
But There’s Something You Should Know About Eating Fish
But before you run out to chow down on a fish burger or buy a bunch of stock in the nearest fishing fleet, there’s something you should know.
Fish are killed, of course. And for ethical vegetarians, that’s reason enough to steer clear. It’s true that some scientists say that fish lack the neurophysiological capacity for conscious awareness of pain and do not feel pain the way humans do. But others say that it is impossible to definitively know whether another creature’s subjective experience is like our own.
What’s certain is that in recent years, fish biologists around the world have discovered substantial evidence that, just like mammals and birds, fish also experience conscious pain. It is now widely accepted that fish produce the same opioids — the body’s innate painkillers — that mammals do.
A 2025 study, for example, found that rainbow trout experience roughly 10 minutes of “moderate to intense pain” during slow asphyxiation after being removed from the water.
And there are other issues as well. Modern fish swim in polluted waters and exist at the top of very long food chains. As a result, many fish today are contaminated with dangerous levels of mercury, polychlorinated biphenyls (PCBs), and other toxins. And industrialized fishing operations are practically strip-mining the oceans, leaving fish stocks depleted, eviscerating marine food chains, and threatening the viability of the commercial fishing industry for future generations.
What about fish farms? They have some big, big problems, too, which we’ll explore below. So many people are wondering whether there are any better ways to obtain the health benefits of eating fish without devastating our oceans or exposing consumers to dangerous levels of pollution.
Types of Fishing
When many of us think of fishing, we conjure up images of intrepid fishermen in yellow oilskin jackets bravely sailing out of the harbour, enduring lashing rain and fierce winds, and returning at the end of the day with a fresh catch. That romantic vision has nothing to do with how most fish are caught these days. The modern fishing industry relies on two methods for the vast majority of its product: trawling in oceans and seas, and farming in human-made lakes and tanks.
Wild-Caught Fish
Fish labeled as “wild-caught” come from the ocean through commercial fishing methods. There are several huge problems with wild-caught fish.
Overfishing
Overfishing is exactly what it sounds like. We’re pulling more fish from the ocean than the ecosystem can replenish, creating an unsustainable system that has put certain species on the brink of extinction. Overfishing has been a problem since at least the early 1800s, when the whale population was severely affected by humans seeking blubber for lamp oil.
Commercial fishing industries harvest 92 million metric tonnes (around 200 billion pounds) of sea life out of the ocean every year. That’s more than half a billion pounds every single day. And according to the FAO, over a third of the world’s fish stocks are already being fished beyond sustainable levels. A 2024 investigation published in Science found the situation may be even worse than official figures suggest, with the number of collapsed fisheries likely 85% higher than currently reported.
One obvious outcome of this collapse is that there will be no more fish for us. We’ll regale our wide-eyed grandchildren with unbelievable tales of shelves loaded with cans of wild-caught salmon.
We don’t know exactly how removing entire species from the web of ocean life will affect the rest of the food chain and ecosystem, but various models make it clear that we can expect devastation, leading to dead zones and impaired human health. As ocean biodiversity declines, more room is left for invasive species to colonize coastlines and further destabilize ecosystems. As algae-eating fish go extinct, algal blooms can pollute water and contribute to epidemics of disease in humans (and other species, too).
And while commercial fishing produces the vast majority of the fish we eat, there are still plenty of places where old-style fishing cultures are still catching enough for subsistence and a local economy. These cultures are being devastated by the die-off of their preferred seafood sources due to overfishing.
Bycatch
Commercial fishing nets — also called trawling nets — are no joke. They can be up to two miles long and around the size of a football field at their opening. Do you think a net that large will only catch the salmon, shrimp, or tuna that commercial fishers set out to catch?
The answer turns out to be a resounding “no.” Estimates suggest approximately 40% of the global commercial catch is actually not the intended species. This 40% is called bycatch and can include species like dolphins, sharks, whales, sea turtles, and anything else that happens to be swimming through at the time of the catch.
Besides being incredibly sad, bycatch causes other problems. It leads to more overfishing, slowing down the recovery time for exploited and overexploited species. It kills already endangered species like sea turtles and seabirds. They may be caught in the nets and killed, or they could become entangled in netting debris, carrying around pieces that are disfiguring and can even drown or starve them. Bycatch is also extremely wasteful, both physically and financially. Even fisheries certified as sustainable have been found to discard a large percentage of their catches.
Destruction of Ocean Ecosystems
Millions of ocean species cannot be killed without also disrupting the ocean itself. Any dead carcasses thrown overboard can attract scavenging species and disrupt the ocean’s nutrient balance.
Plastic Pollution
Netting debris often gets caught in the physical ocean environment, like the seabed, coral reefs, and sponges. A 2019 Greenpeace report found that the biggest source of plastic pollution in our planet’s oceans comes from fishing. More than 640,000 tons of lost or abandoned fishing gear find their way into the ocean every year. Just to give you an alarming visual, that’s the weight equivalent of about 210,000 SUVs, or a new SUV hitting the water every two and a half minutes, all year long.
This “ghost gear,” as it is known, kills hundreds of giant sea turtles annually, and can compromise the ability of whales to filter water as they feed. It can also suffocate seabirds, crustaceans, and small fish.
Farm-Raised Fish
Spurred on by the depletion of the oceans and the stocks of fish that swim in them, an ever-growing share of the world’s fish is being produced in fish farms. In fact, over half the world’s fish harvest now comes from aquaculture. Unfortunately, this isn’t great for the oceans, either.
Farm-raised fish contribute significantly to pollution and disease. The largest source is the waste that fish produce, as well as uneaten food that sinks to the bottom of the pens and contaminates the water. Chemicals, such as pesticides, antibiotics, disinfectants, and anti-corrosives, are widely used in fish farming to prevent the spread of diseases. However, these chemicals contaminate the water, the equipment, and the fish themselves.
And in a protocol similar to factory farming of cows and pigs, fish are given routine doses of antibiotics simply to keep them alive under miserable conditions. The overuse of antibiotics in these environments poses a significant public health risk, increasing the likelihood that antibiotic-resistant bacteria will enter our food system.
Nutritionally, there are measurable differences between farm‑raised and wild fish. In a direct comparison of farmed and wild Atlantic salmon, researchers found that farmed salmon fillets contained substantially more total fat and a markedly higher omega‑6 to omega‑3 fatty‑acid ratio than wild salmon. This reduces the concentrations of anti‑inflammatory long‑chain omega‑3s (EPA and DHA) that are especially abundant in wild salmon. That said, a single 150-gram portion of salmon, whether farmed or wild, will still contribute more EPA and DHA than the recommended weekly intake for adults.
You may have noticed a color difference between farm-raised and wild-caught salmon. Because fish raised on farms don’t have access to things in the ocean that would naturally give them their carotenoid-rich pink pigmentation, like crustaceans and algae, most salmon farmers add pigmenting compounds like astaxanthin to their salmon feed to enhance the coloring that consumers want. These chemical dyes that turn otherwise grey fish into a rich reddish hue are actually the most expensive part of farm-raised salmon feed.
Historically, producing one pound of farmed salmon required roughly five pounds of wild-caught forage fish — species like mackerel, anchovies, or sardines — once processed into fishmeal and fish oil, according to a landmark 2009 analysis in the Proceedings of the National Academy of Sciences. Many of these forage fish are threatened or ecologically important, and their harvest for fish feed can contribute to population declines and disrupt marine food webs.
In a bit of good news, salmon farming has become dramatically more efficient at using marine ingredients since then. Recent analyses using updated accounting methods show that farmed salmon and trout are now roughly “net neutral” — producing about as much fish biomass as they consume in feed — while fed aquaculture as a whole now produces three to four times more fish than it uses as feed. Nonetheless, farmed fish diets may still include plant-based ingredients such as GMO soybeans and byproducts from land-based livestock operations, raising questions about resource use, environmental impact, and the overall sustainability of these systems.
Genetically Engineered Fish: A Threat That May Have Passed (For Now)
For years, the fish farming industry pursued genetically engineered (GE) fish as the next frontier. At least 35 fish species were being genetically engineered around the world, including trout, catfish, salmon, and tilapia — often modified with growth hormone genes to make them grow faster and larger.
The most controversial example was AquaBounty Technologies’ AquAdvantage Salmon, approved by the FDA in 2015 despite significant opposition from consumers, environmental groups, and members of Congress. The salmon was engineered to grow twice as fast as regular salmon, raising serious concerns about what would happen if these fish escaped into the wild and crossbred with wild populations, potentially eliminating natural salmon stocks.
The good news? By 2024, AquaBounty faced significant financial challenges and operational setbacks, effectively endingcommercial production of GE salmon in the North America. As of now, genetically engineered fish are not widely available in the marketplace.
However, the technology still exists, and regulatory frameworks vary globally. The AquAdvantage salmon saga serves as an important reminder to stay vigilant about novel food technologies being rushed to market without adequate long-term safety studies or environmental impact assessments. Just because GE fish aren’t currently on your plate doesn’t mean the issue has disappeared permanently.
Can Fish Be Farmed Sustainably?
Since our oceans are increasingly depleted, and human appetite for fish has been on the rise, the question naturally emerges: Is there a way that fish can be farmed safely and sustainably?
With farm-raised fish production outpacing that of wild-caught fish and of global beef, the good news is that there’s a growing conversation about sustainability. The goal of more sustainable fish farms is to raise healthy fish that don’t damage local ecosystems.
How has that been going? When we look at aquaculture operations that have adopted practices aimed at improving sustainability, concerns remain about the environmental and health impacts of farmed fish. Even when so-called “more sustainable” farms limit non‑essential additives, synthetic chemicals, and routine use of antibiotics or hormones, these measures do not fully eliminate potential risks.
While some producers are incorporating natural, plant‑derived feed components and alternative health-promoting ingredients (e.g., phytogenics, probiotics) to support fish welfare and disease resistance, the long-term effects of these interventions remain unclear. Aquaculture continues to pose challenges related to ecological impact, feed sourcing, and chemical exposure, making it far from a truly sustainable or risk-free source of seafood.
More sustainable fish farms are vigilant about monitoring water quality to ensure they don’t produce pollution levels that harm local ecosystems or native wild fish. Some are in the deep open ocean, where the water is more pristine, and currents are strong and steady enough to continually flush the farms of fish waste and pests such as sea lice. Others are placed in zero-waste, closed-loop land-based systems.
While practices like these can be a big step forward, the reality is that there is stunningly little government oversight of the aquaculture industry, and claims of “sustainable” may or may not mean anything. So if you wish to partake, here are a couple of labels that might mean something:
- The Global Aquaculture Alliance developed the voluntary Best Aquaculture Practices Certification. The standards address environmental and social responsibility, animal welfare, food safety, and traceability.
- The Aquaculture Stewardship Council, founded by the World Wildlife Fund and the Dutch Sustainable Trade Initiative, certifies responsibly farmed seafood and manages global standards for sustainable aquaculture. It doesn’t represent the most stringent of standards, but it’s a meaningful step in the right direction.
- And probably the single best “one stop shop” resource for reviewing the sustainability of different fish is Monterey Bay Aquarium’s Seafood Watch, linked here.
However, even if aquaculture were to evolve into a sustainable model, fish eaters would still face another concerning problem: contamination.
Contaminants in Fish
Fish tissue tends to be fatty, and most environmental contaminants are fat-soluble. Complicating this problem is that larger fish eat smaller fish, so contaminants become more concentrated as they move up the food chain. And a lot of the fish we love to eat are pretty high on that food chain. You can’t see the contaminants, so you never know what — or how much — of something harmful could be lurking in the fish you buy.
What are some of the most common contaminants in fish, and where do they come from?
Nearly all fish contain at least trace amounts of mercury, and some contain a significant amount. Mercury is a toxic metal. It can cause neurological and chromosomal problems and harm unborn babies if they are exposed during pregnancy.
Certain species tend to contain more mercury than others, largely due to their predatory position in the aquatic food chain. For this reason, many experts advise avoiding the consumption of shark, swordfish, tilefish, and king mackerel, as these fish tend to eat many smaller fish, which contributes to their mercury levels. Albacore, yellowfin, and bigeye tuna are also very high in mercury.
And fish lower on the food chain can still contain mercury. This is why pregnant women are advised to limit or avoid certain high-mercury fish to protect fetal development
Polychlorinated biphenyls (PCBs) are toxic, artificial industrial compounds that can build up in the fatty tissue of fish. Unfortunately, even though the use of PCBs has been banned in many places, they tend to stick around in the environment for a long time. The EPA considers fish a persistent source of PCBs in the human diet.
Consuming PCBs can have lasting neurological, endocrine, circulatory, digestive, and central nervous system effects. Some states have advised people to limit their consumption of all fish and shellfish from nearby freshwater or coastal areas due to a high risk of PCB contamination. Research has shown that PCBs can cause congenital disabilities, smaller birth weight, and delayed learning among infants, and older adults can experience reduced memory and learning.
In addition to mercury and PCBs, recent studies show that per- and polyfluoroalkyl substances (PFAS) — so-called “forever chemicals” — are increasingly found in both farmed and wild fish. PFAS can accumulate in human tissue over time, raising potential health concerns for frequent seafood consumers.
Dioxins are cancer-causing industrial pollutants and have been called some of the most toxic chemicals known to science. They’re also known to harm reproduction and human development. Unfortunately, fish are a major source of dioxins in the human diet. Like mercury, dioxin tends to accumulate in larger fish up the food chain. In fact, EPA data show that TCDD — the most-studied dioxin compound — can reach concentrations in fish tissue roughly 38,000 to 128,000 times higher than in the surrounding water.
Pesticide residues from factory farms can also end up in the fish you eat, by way of the waterways that run into the ocean.
And lastly, plastics from landfills can end up in the water, be eaten by the fish, and ultimately end up in your body. Research has shown that plastics can linger throughout generations of fish.
The good news for farmed-fish fans is that in recent years, regulatory changes have brought down the contamination level in farmed fish. It’s still a real concern, but it may, in some cases, be lower than in wild-caught fish.
What You Can Do
Probably the most important question to ask after recognizing the concerns about eating fish is: What can you do about it?
One option, of course, is to reduce (or eliminate) your fish consumption altogether. The fish will be grateful, and so will the oceans. Plus, you’ll be sparing yourself exposure to heavy metals, microplastics, and other contaminants.
If you do choose to eat seafood, you may want to choose fish from one of the more sustainable and low mercury options, such as wild salmon, sardines, anchovies, and herring, which are all uniquely high in omega-3 fatty acids and tend to be low in mercury.
You can buy wild-caught fish or farm-raised fish certified by third-party organizations such as BAP (Best Aquaculture Practices), ASC Pangasius, Naturland, Canada Organic, or the MSC (Marine Stewardship Council) to minimize contamination and ensure sustainability. Or take advantage of the Monterey Bay Aquarium’s Seafood Watch, which provides a guide to how responsibly certain types and origins of fish are produced.
And if the main reason you’re eating fish is for DHA and EPA, consider taking an algae-based DHA and EPA supplement instead. Pair this with a wide variety of fruits, vegetables, legumes, nuts, and seeds, and you can reap the benefits of these long-chain fatty acids without the risk of marine contaminants, the ethical problems associated with all forms of animal agriculture, and the environmental concerns raised by eating fish.
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About the comments: This article may stir some controversy. In the comments below, I encourage you to (respectfully) share your opinions and experiences. Robust dialogue can make us all wiser and healthier. Just please remember that most other people reading and engaging care about the planet, animals, and the well-being of future generations, like you do — even if they eat or think differently.
Tell us in the comments:
- What is your biggest takeaway from this article?
- Do you eat fish? Why or why not?
- Do you do anything special to ensure you are getting enough DHA and EPA?
Featured Image: iStock.com/Natissima
