How much and which fish should you eat, if at all? We sum up the pros and cons: health benefits, mercury, overfishing and even the feelings of the fish themselves.
It's one of the clearer recent health messages from nutrition science: eat less red meat, eat more fish.
But as with all 21st century consumption, there's a downside: we've devoured most of the ocean's bounty already, and poisoned much of what's left.
Age of pisces
Pescetarians' position on the dietary continuum is a slippery one: we're distrusted both by carnists, who feel judged by us and probably think we're not properly red-blooded, and by vegetarians, who think we're too chicken to take the ultimate ethical step. (Also they're continually annoyed by some pescetarians carelessly calling themselves “vegetarians”. They're right: we're not.)
We associate fish, and even eating fish to some extent, with cold-bloodedness. Literature's best-known piscivore, Gollum, shown here in The Lord of the Rings Trilogy, New Line Productions.
I became pescetarian at the start of the new millennium, which I celebrated with champagne and sinking my teeth into one final unfortunate chicken.
But I continued eating fish, because, well, I liked it, vaguely felt I needed the protein, and because my chief rationale for quitting birds and beasts – i.e. that if I wasn't prepared to slaughter them myself I couldn't expect others to – didn't apply to fish.
Killing and gutting a cold, clammy creature with little brain and no discernible heart-beat that didn't cry out? Yes, I thought I could do that.
But try as I might not to think about it too much, my pescetariansm has been making me queasy. Fish has started to seem increasingly flesh-like to me, and so it is: protein-packed muscle from a living animal. Fish is Meat.
On a recent media trip to Katse Dam Fish Farm in Lesotho, I thought the time had come to stop being mentally and ethically lazy about pisces-related issues, and tackle them once and for all. Here's my round-up:
Fish-eating and your health
Fish is nutritionally excellent, packed with lean protein, vitamins and essential omega-3 fatty acids. The latter have been linked most strongly to heart health, but also to a slew of other benefits, from better vision to reduced colon cancer risk.
The current recommendation, from the American Heart Association (AHA) among other international nutrition advisories, is to eat fish at least twice a week. Note that they don't mean we should feast on red meat as usual AND eat fish; the key is to swop meals of fatty red meat for fish meals.
To optimise the benefit, make at least one of your weekly fish meals of oily fish (rich in omega-3) e.g. salmon, mackerel, sardines, trout, herring, anchovies, tuna.
And obviously, the fish shouldn't be battered, deep fried or smothered in rich sauce – that's likely just as bad as high-fat red meat.
What about fish oil supplements?
There's some uncertainty about whether the oils alone are doing the trick – evidence on the benefits of fish oil taken in supplement form is not as strong as getting your omega-3 from eating fish.
Is skipping fish altogether unhealthy?
Are pescetarians healthier than vegetarians? Hard to say. Both are considered good nutritional routes to follow, and almost certainly better than a typical meat-heavy western diet. However, whether being pescetarian or vegetarian is better for you than being a very health-conscious meat-eater who sticks to a limited amount of lean red meat is also hard to say.
Many dieticians do worry about vegetarians, and vegans particularly, not getting sufficient omega-3, among certain other nutrients that are abundant in animal products. It's not impossible to get these from plant sources if you're clued-up and diligent about your nutrition, but it's easier and likely more effective to get them from fish.
As the AHA says: “Some of the value of omega-3 fatty acids can be found in flaxseed, walnuts, soybeans and canola oils. But it’s really not the same as finding a way to get fish into your diet.”
What about mercury?
Most fish contain trace amounts of mercury, but although it's important to be aware of this in certain higher-risk cases, we shouldn't let it put us off fish and thus miss out on its nutritional benefits, which outweigh mercury risks by far.
The concern relates rather to certain types of fish that contain relatively high levels of mercury, to communities eating fish regularly from potentially contaminated sources, and to mercury's potential harm to the developing nervous systems of children and unborn babies.
For children, pregnant women and women who are planning to become pregnant in the near future, the recommendation is to avoid eating larger, long-lived predator fish like swordfish, which are higher in mercury, and limiting all fish consumption to two meals a week. Read the recommendations in detail.
Fish-eating and the environment
85% of the planet´s fish stocks are either overexploited or exploited to their maximum, according to the United Nation’s Food and Agricultural Organisation (FAO). As this important protein food source dwindles, so do the livelihoods of millions of people involved in the fishing industry.
Fishing does harm beyond depleting fish stocks. Excessive harvesting of a single species can upset the balance of entire marine ecosystems. Also, many other fish and endangered species (e.g. albatrosses, turtles) are caught as unintended bycatch. The FAO estimates that a quarter of creatures caught are thrown back, often maimed or dead.
This dismal state of affairs doesn't mean we have to give up our sushi (at least not quite yet), but it does mean that when we do enjoy fish, we must ensure it's from the least damaging and most sustainable sources. The South African Sustainable Seafood Initiative (SASSI) has excellent consumer resources for quickly guiding you in this regard. Read more on sustainable seafood choices.
Can fish farming solve the crisis?
As wild-caught fishing is flatlining, fish farming (or aquaculture), now responsible for a third to a half of total fish supply, is growing rapidly. It takes up considerably less space than land-based agriculture, and likely fewer resources as fish are farmed in a restricted area and don't require the ocean-going vessels of wild-caught fish.
World fisheries harvest showing wild capture vs aquaculture, in million tonnes, 1950-2010. (FAO)
These positives are diluted by a number of environmental concerns, however. Carnivorous farmed fish species still need to be fed on wild fish, for one thing, and fish kept in a specific area produce waste that can contaminate the surrounding environment.
Nonetheless, carefully maintained fish farms such as Katse Dam, which supplies rainbow trout to Woolworths, do strive to minimize negative impacts and are an important element in easing pressure on our oceans and supplying the growing human population's vast demand for protein. Several farmed species are on on SASSI's Green List of fish you can eat with minimal guilt. Read more about sustainable aquaculture and Katse Dam.
Do fish feel?
It's convenient to think of fish as insensate, and it's ingrained in us that they are: being called a “cold fish” suggests a chilly lack of feeling.
But unfortunately for otherwise animal-loving pescetarians such as myself, fish have pretty highly developed nervous systems. Can they feel love and hate and joy and despair? Who knows. Can they feel fear? Probably. Can they feel pain and stress? Indubitably.
The latest studies on fish suggest that we have not been giving them their due in terms of complexity and intelligence - and capacity for suffering. Depending on the species, they can learn, recognise shoal mates, enjoy sensations of touch and communicate with sub-audible squeaks and grunts. Read more about fish sentience.
A personal conclusion
Because of the strong positive health evidence, I've decided to remain an uneasy pescetarian for the time being, limiting myself to two fish meals a week from sources I can, to the best of my knowledge, ascertain are from sustainable sources. I'm going to eat a more varied fish diet instead of always just cranking open another can of tuna, and I'll aim to make most of my fish meals from oil-rich species.
I'm also going to try to catch some of these meals myself. There's nothing like sourcing your own food (especially if it has a heart and nervous system) to really get to grips with the real costs and ethical sacrifices required to get it to your plate.
We'll see. If I turn out to be too squeamish to tangle with hook and line, I'll have to ask myself why.
I concede the moral high ground to those who won't compromise on causing any creature potential suffering merely to satisfy human appetite, and I remain open to persuasion that my 104 fish meals a year could be reduced with healthy plant-based alternatives.
- Olivia Rose-Innes, EnviroHealth Editor, Health24, August 2012