Seaspiracy Debunks 6 Fishy Myths about ‘Healthy’ and ‘Sustainable’ Seafood

Author: Natasha Maria

We’ve all seen the adverts; happy fish swimming around in a healthy-looking ocean before being carefully scooped up by a white-bearded captain and instantaneously becoming a crispy fish fillet. Such images have been permanently ingrained into our psyche since childhood, conveniently fitting a narrative pumped out by the seafood industry. Sadly, fish and sea life still remain forgotten from conversations surrounding ethics, health and the environment; a slip of the mind conveniently fuelled by an industry that thrives on dubious myths surrounding health ‘benefits’ alongside woeful ‘sustainability’ assertions. The time has come to put fish, and fishing, firmly on the table — but not on our plates.

So it was a breath of fresh air when I witnessed Seaspiracy sprint up the Netflix ‘most popular’ charts around the world, making waves with it’s no-nonsense revelations into the seafood industry. The documentary breaks the radio silence we’ve seen from environmental and health organisations who are failing to address the elephant — or rather the whale — in the room, finally starting the much-needed conversation around the unprecedented destruction of our oceans alongside the health impacts of eating sea life and marine animals.

So, which fishy myths could I sink after watching Seaspiracy? Here are my top six:

1. Without fish, we can’t get omega 3 or other essential fatty acids in our diets.

Now, we couldn’t talk about fish without the inevitable trip down omega 3 lane. Just like the fallacies of ‘meat = protein’ and ‘cow’s milk = calcium’, we have the tired old tale of ‘fish = omega 3’.

While these omega fatty acids are indeed essential for health — including the healthy functioning of the heart, brain and nervous system — it’s not fish that are producing them, it’s the algae cells they eat. Fish are technically the middle man; as the fish eat omega-rich algae and their flesh builds up stores of omega 3. This essential acid can easily be obtained by eating the plants directly, or by incorporating chia seeds, ground flaxseed, flaxseed oil, canola oil, walnuts, soybeans and/or green leafy vegetables into your diet.

While many people associate fish and fish oils with healthy heart function, very often the risks far outweigh the benefits. In several gold standard reviews, it was found that obtaining essential fatty acids from plant foods (as opposed to fish) may reduce the risk of a cardiovascular event or abnormal heart rhythm, with EPA and DHA from oily fish having little to no positive effect on heart health1. A 2018 review published in the British Journal of Nutrition found that obtaining essential fatty acids from plant-based sources was linked to a reduced risk of heart disease2.

2. Fish contain safe levels of toxins.

With the oceans becoming increasingly contaminated with various sources of industrial runoff, agricultural inputs and other toxins, fish are essentially swimming, living and feeding in a soup of pollution and micro plastics3. Common man-made pollutants include agrochemicals (such as pesticides), fertilisers from agricultural farming, detergents, industrial chemicals, polychlorinated biphenyls (PCBs), dioxins, mercury and sewage. Yum.

Compounding these issues are the way in which fish eat each other, with one fish eating a smaller fish, and so on. This creates an effect known as bioaccumulation, where contaminants accumulate throughout the food web and are ultimately most concentrated by the fish sitting at the top of the chain — the fish which is often eaten by humans.

A recent study of consumers in the US found that 82% of exposure to methylmercury (a type of mercury in the environment usually due to industrial pollution) was directly due to eating seafood4, with a second study indicating that such levels appear to be on the rise. Mercury is particularly common in fish — whether ocean caught or intensively farmed — and can cause damage to immune, nervous and enzyme systems, as well as presenting as a significant neurotoxin.

Mercury poisoning particularly affects the development of babies in the womb, potentially causing damage to the brain and nervous system. Later on, this can cause symptoms such as issues with memory, attention, motor skills, language and visual spatial skills. In adults, repeated exposure to mercury has been shown to cause paralysis, incoherent speech, delirium, damage to nervous and immune systems, kidney damage, tremors, insomnia, neuromuscular effects and motor dysfunction19. In some cases, extreme exposure has been fatal.

Polychlorinated biphenyls (PCBs) are also of great concern, which have been found to be present in fatty foods such as fish, milk and meat. While now banned, PCBs persist in the environment and continue to contaminate our ecosystems. PCBs have been linked to the development of heart disease, cancer, infertility and harming developing foetuses5. And if that’s not enough, dioxins — commonly found in fish — are an additional concern, which cause reproductive problems, immune system damage, hormonal disruption and cancer6. Definitely not a list of ingredients that’s wetting the appetite, that’s for sure.

3. Even though the ocean is now riddled with microplastics, fish and sea animals are still safe to eat.

Knowing there may be around 8.3 million pieces of microplastic per cubic metre of ocean is deeply worrying. Scientists have found microplastics in 114 aquatic species, more than half of which are consumed by humans7, and other research has demonstrated that plastic particles are able to translocate and reach all organs in the body8, with one study finding plastic had even reached the livers of fish9. Other studies have found up to 90 microplastics in just one portion of seafood10, as well as being present in some canned fish11. Marine Biologist Sedat Gündoğdu stated that “all food ... derived from marine environments is polluted with plastic”20.

As Seaspiracy points out, plastic contains a wide range of additives, including pigments, water repellents, flame retardants, phthalates12 — all sorts of nasties you wouldn’t want near your food, much less inside it. While the human body is able to remove and eliminate some of these microplastics, preliminary research into the impact on human health indicates that they may cause inflammation in the body, disruption to the gut and create ongoing exposure to persistent chemical additives. Overall, the safety of eating any quantity of tiny plastic particles — a relatively new phenomenon — is vastly under-researched, but the health consequences linked to some of the chemical additives is long known. Some of the array of chemicals in microplastics interfere with hormone function, while others are well known cancer-causing carcinogens or have strong links to birth defects12.

4. Farmed fish are safer and healthier to eat.

The temptation to turn to farmed fish to avoid the toxic, microplastic soup that is now the ocean is understandable, but far from the solution. Farmed fish are fed fishmeal, which is composed largely of concentrated ground up fish… from the ocean. And, all chemical toxins aside, they are full of… you guessed it… microplastics! A recent study found that commercial fish from farms contained extremely high levels of microplastics which were making their way into the human food chain13. Fish which are killed and used as fishmeal for fish farms tend to have high concentrations of microplastics; this was confirmed in a literature review which demonstrated that a shocking 60% of wild fish — 198 species which were captured from the oceans of 24 different countries — contained microplastics in their organs, and many of these fish were killed and processed into a concentrated feed for fish farms20.

Farmed fish are also notorious for carrying diseases, toxins, additives and containing high levels of antibiotics which are needed to survive the often cramped conditions. A study comparing wild to farmed salmon, for example, found that the farmed fish had consistently higher levels of contaminants, including toxic PCBs15 and chlorinated pesticides (mmmm, tasty!), outweighing any possible health benefits21.

Investigations into some Scottish salmon farms — highlighted by Seaspiracy — demonstrated fish dying from anemia, lice infestation, infectious diseases, chlamydia and heart disease. Additives were also found to be used on a widespread scale; salmon are naturally grey in colour, causing farmers to choose their shade of ‘pinkness’ from a colour chart before feeding the pigmented additives to fish, making them a pink shade of the farmers’ choosing. I don’t know about you, but I’m starting to go off my food.

5. Eating fish is a good alternative to eating land-based animals because they ‘don’t feel pain’.

A scientific panel in the EU Commission concluded that fish feel pain and experience fear. And just like other sea life, such as whales and dolphins, fish have social lives, families and friends, and often team up with others to search and find food. Professor Donald Broom of the University of Cambridge points out that fish have sensory differences to land mammals due to being underwater, but do have pain receptor cells, neural pathways and electrophysiological responses to pain stimuli15. In fact, research has consistently shown that the physiology, neurobiology and brain activity of many fish species is directly comparable to mammals, with an ability to produce painkillers (opioids) as a result of injury or painful event, much like other animals16.

While still deeply under-researched, fish are sentient, living beings with a proven ability to feel pain, fear and suffer as they are dragged to boat decks and suffocated in their billions. The best way to avoid suffering is simply to leave all living beings off your plate.

6. Eating fish is sustainable.

Seaspiracy did a great job of sinking this myth once and for all. Our oceans are being rapidly depleted of fish species, causing huge ecological imbalances that directly affect our survival as a species. Estimates suggest that if current fishing practises continue, we may have an empty ocean by 2048, with many fish populations already on the brink of collapse17.

Eating fish is far from sustainable. Trawling nets used by industrial fisheries are hugely destructive, ripping out sea plants and churning up the sediment at the bottom of the ocean, causing stored carbon to be released back into the atmosphere — adding further to global overheating. The loss of larger sea mammals in the food chain, such as whales, dolphins and porpoises, which are either struggling to find food or killed ‘accidentally’ in fishing nets, is continuing to wreak havoc on ocean ecosystems, and is even altering critical chemical cycles needed for human survival. Seaspiracy certainly shocked me when it pointed out that any large-scale extraction and killing of wildlife couldn’t ever be sustainable, and they were right. Plastic pollution also remains a prominent problem, with the fishing industry dumping a colossal 640,000 tonnes of nets, lines and pots into the sea every year18.

Looking at farmed fish, the picture is equally dire: aside from the amount of feed needed for these fish, they are often riddled with disease, create huge levels of waste, and add to plastic pollution problems. In one example demonstrated by Seaspiracy, it was estimated that the Scottish salmon farming industry produces organic waste equivalent to the entire population of Scotland each year.

Many health and environmentally conscious people turn to fish as a replacement for eating land-based animals, hoping to escape the cruelty, health implications and environmental footprint. But if Seaspiracy has taught us anything, seafood is far from healthy or sustainable. And while some communities largely rely on sea animals as a food source and have little choice, a large percentage of us simply don’t have to. Knowing the environmental destruction and worrying impacts on our health, it’s high time we leave fish off our plates - for the animals, the planet and our own health.

Five things you can do to help:

  1. Share this blog article.
  2. Watch & share Seaspiracy. Encourage (or challenge) your friends to watch it.
  3. Leave seafood and animal products off your plate and replace with tasty plant-based alternatives!
  4. Start a Fish Save Chapter in your area.
  5. Ask environmental organisations to speak up about the impact of fishing on the oceans

Read more blogs:


    1. New Cochrane health evidence challenges belief that omega 3 supplements reduce risk of heart disease, stroke or death, Cochrane
    2. The association and dose-response relationship between dietary intake of α-linolenic acid and risk of CHD: a systematic review and meta-analysis of cohort studies, National Library of Medicine
    3. Marine pollution, explained, National Geographic
    4. Why fish may become more toxic than ever, Medical News Today
    5. Why Public Health Policy Should Promote Plant Omega-3 in Preference to Fish Oils, Viva!
    6. Dioxins and their effects on human health, World Health Organization
    7. Sources, Fate and Effects of Microplastics in the Marine Environment, GESAMP
    8. Microplastics in Seafood and the Implications for Human Health, National Centre for Biotechnology Information
    9. Microplastics in livers of European anchovies, Environmental Pollution
    10. Microplastics in bivalves cultured for human consumption, Environmental Pollution
    11. Microplastic and mesoplastic contamination in canned sardines and sprats, Science of the Total Environment
    12. We Know Plastic Is Harming Marine Life. What About Us?, National Geographic
    13. Microplastics in fish and fishmeal: an emerging environmental challenge?, Nature
    14. The Fish Report, Viva!
    15. Fish are Sentient, Fish Counts
    16. It’s Official: Fish Feel Pain, Smithsonian Magazine
    17. Seafood May Be Gone by 2048, Study Says, National Geographic
    18. Dumped fishing gear is biggest plastic polluter in ocean, finds report, Guardian
    19. Mercury and health, World Health Organization
    20. Fish Farming has a Problem, Environmental Health News
    21. Lipid composition and contaminants in farmed and wild salmon, Environ Sci Technol

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