Fish are arguably the most nutritionally valuable food of animal-origin in the human diet and although you can certainly live healthily without them, their consumption is more strongly linked with positive health outcomes than any other animal product.
I’ve been following a Pescatarian style of eating since the completion of my Pescatarian Cookbook last year, which has greatly enhanced my interest in the topic of fish intake and human health..
When we look at observational data of fish intake we can see time and time again that people who eat more fish tend to have a lower risk of negative health outcomes.
Fish is also the only form of animal protein that Health Canada goes out of their way to specify that Canadians consume in a specific weekly amount (150 grams weekly).
Why Does Health Canada Want You To Eat Fish?
Simply put, fish is a source of two very important nutrients that tend to be found scarcely in other foods: Vitamin D and Omega-3 fatty acids.
These two essential nutrients contribute greatly to the health benefits of fish consumption, a fact that is amplified when we consider that it is very easy for the average consumer to fall short in these two nutrients, simply because they are not found in a wide array of foods.
Vitamin D, for example, is widely under consumed in the Canada.
Simply put, there is no other naturally occurring source in our food system that contains both of these essential nutrients in the same quantities that fish does.
And that, my friends, is precisely why Leigh Merotto and I are here today to GO FISH!
Wild Vs Farmed Fish … Does It Matter?
Leigh Merotto RD, MHSc & Andy De Santis RD MPH
Keeping all of what has been said so far in mind, my colleague Leigh came up with the brilliant idea for us to team up and “go fish” for facts on the critical differences between wild caught and farmed fish.
As the health benefits of fish consumption continue to gain notoriety, the consumer demand for fish grows.
In order to meet this demand, the way fish are being sourced has completely changed.
Unlike in years past, fish are no longer exclusively wild caught and “fish farms”, also known as aquaculture, have taken over as the primary source of fish production.
The emergence of these farms has led to concerns and questions over whether or not the fish we consume today is as healthy and safe as it used to be.
That is precisely the question that Leigh and I intend to explore in today’s article.
Spotlight On Salmon
For the sake of today’s content we will focus our discussion on salmon for the simple fact that is the most widely sold and consumed fish variety in Canada.
What Are The Differences Between Farmed and Wild Salmon?
In order to ultimately judge whether or not it matter which type of salmon you choose to consume, we will go through a number of criteria, starting with the nutritional differences and then delving into deeper issues surrounding potential contaminants, environmental impacts and ethical considerations of selecting farmed vs wild salmon.
Comparing Wild vs Farmed Atlantic Salmon using the Canadian Nutrient File database we found that:
- Vitamin D levels are comparable
- Farmed salmon contain 3x the level of saturated fat and about 25% more omega-3 fatty acids
- Farmed salmon contain 50% more calories (208 vs 142)
- Minimal other notable differences in nutrient values
Modest differences that, depending on a given person’s dietary pattern, may or may not bear relevance.
We did a price comparison at a local grocery chain here in Toronto and found that, when in season, wild caught salmon tends to cost about 50% more when comparing fresh varieties.
This price difference could obviously fluctuate greatly depending on the grocer, the source of the fish, whether it is fresh vs frozen, organic or not, and so on.
Keep in mind that it is very possible that one could find frozen wild caught salmon at a lower price than farmed fresh salmon.
Generally speaking, wild salmon contain higher levels of mercury (due to bioaccumulation) but farmed fish contain higher levels of other potentially carcinogenic contaminants such as dioxins and PCBs.
The levels of these compounds are monitored and must remain within acceptable ranges as set by Health Canada, even if there is variation between wild and farmed varieties.
It seems to be generally understood that the level of contamination in farmed salmon is more of a concern than in wild fish, but that some farmed salmon are better than others.
For example, European-raised salmon have significantly greater contaminant loads than those raised in North and South America, so you can reduce your exposure to these compounds by selecting salmon that is sourced from either North or South America, rather than Europe, whenever possible.
There has also been some suggestion that the protective effect of the higher levels of omega 3 fatty acids in farmed fish (about 25%, as previously mentioned) helps to offset any theoretical increased risk that may be associated with the elevated contaminant levels.
Finally, it is also worth noting that the last 10 years have seen a decrease across the board in the level of contaminants found in farmed fish.
As with other farmed agriculture, antibiotics are commonly added to salmon feed to keep stocks healthy and reduce risk of infection (this is not applicable to wild salmon).
In the long-term, however, the continued use of antibiotics could pose threats to human health by fostering the growth of drug-resistant bacteria.
A consideration worth noting given that many of the same antibiotics used in aquaculture are also used to treat human disease.
We encountered what, at the very least, could be described as “mixed views” as to the environmental safety and sustainability of fish farming, also known as aquaculture.
A comprehensive 2013 study out of Norway found that only 2% of fish farms displayed what they described as “unacceptable conditions” and described the farms risk of negative environmental impact to the surrounding areas to be low.
The Food and Agriculture Organisation (FAO) of The United Stations states that: “Fish farming holds tremendous promise in responding to surging demand for food which is taking place due to global population growth.”
There’s more to the story though.
Some researchers are concerned that the crop-based feed used to sustain the fish in these aquaculture settings will lead to environmental strain by driving demand for further land to be used to grow crops.
Other potential concerns include:
- Since most salmon farms are enclosed in ocean or fresh water areas, chemicals and diseases could theoretically pass freely between the farm and fresh water
- Escaped farmed salmon are foreign to Canada and would be considered invasive and threatening species to our native fish were they to escape.
It is important to remember though that wild fishing is not without environmental impacts. Overfishing and exploitation of fisheries and loss of biodiversity due to accidental bycatch and harm to habitats from fishing gear are all too common problems today.
Again, it’s not straight forward to identify a clear winner in this category.
Ethics & Animal Welfare
At the end of the day, both farmed and wild salmon end up on your plate.
Some might argue raising fish for feed is far less ethical than catching them in the wild… someone else might argue the opposite and even more may be completely impartial.
We can’t tell you where you stand on this issue, but here are some insights to consider:
- Wild fish are able to live their lives as nature intended until they are caught either by humans or natural predators (or die of natural causes).
- Farmed fish are bred for our consumption but are also provided with all of life’s necessities: abundant food, clean water, protection from predators, and vaccinations against common diseases.
- Yet farmed fish live in densely packed conditions, contributing to intensified rates of diseases and parasites, and the fish have little room to swim and exercise.
- Farmed fish also face extensive handling during production, transportation and slaughtering, so it is fair to say that suffering is an inevitable part of their life cycle.
Other Noteworthy Considerations Specific To Farmed Salmon
- Some Farmed Salmon Are GMOs (genetically-modified organisms)
As of May 2016, Health Canada approved the sale of the first type of genetically modified food in Canada to be sold, a type of farmed Atlantic salmon capable of growing twice as big as its non-genetically modified counterpart.
Health Canada also states that there is no current evidence to show that the genetic modification of salmon poses any risk to human health or the health of the fish themselves.
Genetically modified salmon are not subject to mandatory labelling, so if you are purchasing Atlantic salmon from the grocery store, you may or may not be getting your hands on a fillet of these GMO fish.
- Farmed Salmon Vs Other Farmed Protein
Not only is it more commonly linked with good health outcomes, farmed salmon also require only a fraction of the resources to raise as compared to other common agriculture.
Life Cycle Analysis (a technique used to assess environmental impact of a product) suggests that farmed salmon demonstrate lower use of key environmental impact measures including energy, water, and land usage, and have better green-house gas emissions than beef, poultry, and pork.
The fresh vs wild caught fish debate is similar to the organic vs conventional produce debate.
Because of the potentially significant price disparity, regularly purchasing wild fish may simply not be an affordable option for many people.
Yes, there are obvious differences between fresh and wild fish but the bottom line for your health, as we understand it today, is quite similar.
For Leigh and I personally, if we had all the money in the world, it is reasonable to say that we’d probably purchase more wild fish simply because it does objectively hold a slight edge when you take into consideration all the facets involved.
With that being said, we would never tell someone with limited financial resources that wild caught fish are an essential selection for good health and there is no compelling evidence to present at this time to suggest farmed fish are in anyway damaging to your health.
One way or another, just make sure that if you are omnivorous, you eat your fish.
Until next time,
Andy & Leigh
PS: Don’t Forget About My Pescatarian Cookbook!