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December 06, 2019 Oliver Fredriksson By Oliver Fredriksson My Articles

Fish Farming | Opinion On Aquaculture

As someone who has grown up with a stretch of Australia’s most pristine ocean in their backyard, fishing was an institution for me. Hours upon hours were spent learning to tie knots, disassembling and reassembling fishing reels and experimenting with different gear to target different species. I learned about the tides, the moon cycles, the water temperatures, the wind and even the bathymetry of my entire immediate coastline to gain the upper hand against the fish I sought to bring home.

Yep, there wasn’t much I didn’t seek to find out about all things fish growing up in a family who loved to 'wet a line'. But this love for fishing taught me much more than how to catch and fillet a fish. As I grew into my teens, the desire for simply landing fish for food or to declare a trip a success waned under the weight of a growing appreciation and respect for what fishing gave me. Fishing had taught me about our environment. About how the most intricate environmental changes could have the most significant impact upon entire marine ecologies. It showed me how intertwined human actions on land and sea were with the infinitely complex and ill understood processes that defined how marine ecosystems functioned.

Make no mistake, this was no ‘light-bulb’ moment where it suddenly all came together for me. It was in every way a slow simmer of my curiosities around how marine and terrestrial environments were connected that lead me to pursue a career in marine science. I needed to understand more about this unseen world that had pilfered such a significant percentage of my waking and subconscious life’s attention.

So, fast forward a few years and there I was. A graduate in marine science from University, with even more questions than when I started. As far as my naive teenage self was concerned, I was supposed to know it all by now. I should know exactly what fish should or shouldn’t be eaten. I should know whether fishing itself is sustainable or whether to give it all up and join the vegetarian movement. I knew in depth about the issues that needed solving, but no idea how they were realistically going to be solved.

What was entirely unambiguous to me was that the oceans on a global scale were in bad shape and getting worse. Entire marine ecosystems were increasingly becoming unnaturally altered, perhaps beyond repair. The influence of both land and marine based human activities had distorted natural patterns of marine ecosystem dynamics and rendered countless species as inevitably at risk of extinction. We were living in the wake of industrialisation. A period in recent history where society’s blind ambition for economic growth valued technological advancement above true understanding of the impacts these advancements would cause. We were living in the midst of one of the most consequential crises that this Earth would ever face, yet had no reasonable or obvious solutions in sight. To me it didn’t matter who made this bed, either way we are all going to have to sleep in it.

I felt both empowered by my new knowledge, yet frustratingly consumed by what felt like an overwhelming lack of tools needed to facilitate meaningful change as just one man. I knew too many people relied upon fish as primary source of protein to simply suggest a cold turkey culling of all fish consumption as a realistic solution. Regulations of Total allowable catch (TAC) based on advanced predictive modelling of fish stocks was already in place in more developed nations with stricter environmental protection regimes. Yet, I knew that didn’t alleviate even close to the amount of damage done by countries not under the same rigid fisheries management plans. After all, estimates of Illegal, Unregulated and Unreported (IUU) fishing catch are still sitting at around 15-30% of global annual catches.1 I was also well aware of aquaculture as a concept, but like many, had also heard the relentless reporting of all that was wrong with it. Despite proudly bolstering a large portion of my opinions on the notion that to believe all you see and hear on TV is to be naive, I did exactly that. I started to believe that even aquaculture may not be a sustainable option. As I said, I knew the issues, not the solutions.

So, with an open mind and somewhat of an anxious impatience to seek genuine solutions, I dove head-first into the very industry that had been so destructively sprayed onto mainstream media. I needed to understand first hand, how fish farms operated and whether the sentiment they often preached about being a solution to growing demand and diminishing supply really held any merit. I left all preconceptions and prejudicial thoughts at the door and became an aquaculture technician, or put more simply, a fish farmer.

So, were they really just the money hungry tycoons from the newspapers and TV? Did they really hold any genuine intentions to preserve marine resources by providing a sustainable option to diminishing wild fish populations? - a cause aquaculture so often seeks to align with. I, of course, cannot speak for every farming operation and their respective honesty to practice what they preach. But, I can speak for what I have personally seen and what I have heard, a perspective that I hope to share to give you more insight into the complexities of aquaculture. In the nature of protecting industry confidentiality, I will spare you the details of exactly how the cogs turn from the inside. But there are a few key points I have taken away that undoubtedly helped shape my own opinion on aquaculture’s place as a sustainable protein producer.

Fish Farming Myths

Myth #1. Farmed fish have poorer health

The first and easiest myth of aquaculture is that of fish welfare. What was abhorrently clear from day one, was that animal welfare meant everything. Despite the multitude of reports of horrendous fish health in aquaculture operations around the world, I was perhaps ignorantly surprised by a team who seemed to care more for the health of the fish than that of their own. Whether the motivation for this is entirely based around ‘pretty’ fish holding greater market value or not, the result is the same. The bottom line is that if the product (fish) is unhealthy or looks untoward, that fish will not sell next to a fish that looks the way people think it should. For this reason, endless investment is poured into fish health via scientists, researchers, veterinarians, technology and feed in order to give farmed fish a life conducive to good health. Of course, this does not exclude the notion that there are poor farm managers, or that mistakes can occur which could lead to ill health in farmed fish. At the end of the day however, regardless of whether the fish health is preserved on a purely monetary motive or on ethical foundations, the end result sees fish that are looked after as well as is humanly possible.

Myth #2. Farmed fish are only fed smaller wild fish

The second ‘fact’ I feel makes perpetual loops of the anti-aquaculture movement, is the common assumption that the diets of farmed fish are comprised entirely of smaller wild fish, and that they consume quantities even greater than would occur naturally in the wild. Not only is this factually incorrect, but aquaculture actually boasts the lowest feed conversion ratio (FCR) of any major protein source. Some farmed salmon now requiring just over 1.1kg of feed needed to produce 1kg of fish. Compared with the ~10kg it takes to add around 1kg of bodyweight to a fish of the same species in the wild, there is little room to argue that producing fish in farms is robbing natural marine resources at a faster rate than wild populations would if left to their own devices.2 Even this figure is not necessarily reflective of the truth behind feed conversion ratios, as in almost all instances they are assuming the feed is purely fish based. Forage fish dependence ratio’s (FFDRs) on the other hand, give far more accurate estimates of the amount of wild caught fish used to produce the amount of fish meal and fish oil required to produce 1 kg of salmon. From 1990 to 2013, the forage fish dependency ratio for fish meal decreased from 4.4kg to 0.7kg in Norwegian salmon farming.3 The result of all this means that only 0.7kg of wild foraged fish is needed to produce 1kg of farmed salmon, with the remaining constituents of fish feed coming from vegetable-based proteins and fillers. It’s a lot of math, I know.

My point, is that the entire aim of the game when it comes to aquaculture is maximising efficiency - growing fish faster and growing fish for less. This may mean experimenting with selective breeding, not indifferent to that done with almost all vegetable-based agriculture, nutritionally tailoring feed to maximise growth, or using new gene editing technology like CRISPR. Whatever the method, if an argument towards reducing aquaculture is claiming sustainability as its basis, I cannot help but question what angle of sustainability it is drawing upon. Using a fraction of the resources to produce the same quantity of product is undoubtedly a more sustainable alternative to hauling fish from the ocean and hoping for the best, with the undesired bycatch thrown lifeless overboard.

Myth #3. Aquaculture pollutes the ocean

Another key issue that is commonly believed when it comes to aquaculture is the level of pollutants that off-shore or near-shore sea-cages create. This is undeniably a real issue, particularly when it comes to farming occurring in relatively low flow waters such as fjords or lakes. Intensive farming in these types of waterways can have a significant impact on the ecology in surrounding nearby waters, with flow on effects to other marine organisms sharing that waterway. Oxygen depleted waterways, excessive nutrient build up resulting from fish waste, and heavy sedimentation below sea cages that has damaged benthic habitats have been observed on a number of occasions in farms lacking thorough environmental management plans.4

What is often over-inflated however, is the overall scale of these impacts, and how far beyond the farm they actually reach. On top of this, the effort directed into avoiding this through research and technological innovations is unparalleled when compared to competing livestock industries like beef, pork or chicken. Careful site selection, rigorous third party environmental testing, and constant reporting to national environmental authorities, are all requisites if you decide to set up a farm of your own. While these barriers protect the environment, they also add garganutan costs to farm operators before they're even allowed to place a fish into the water. When so much risk rests upon meeting constant assessments, you can be damn sure they are doing everything possible to avoid impact below the cages. 

Allow aquaculture to learn and progress 

Sure, aquaculture has made some mistakes in the way things once operated, but has every other form of agriculture not similarly gone through developmental phases? Every single vegetable that has ever been grown commercially has been cultivated the way it has off the back of generations of trial and error as to what works and doesn’t from a productivity and environmental impact perspective. Aquaculture, like its older food cultivating predecessors, is similarly going through these trial and error phases, only at triple speed and with the worlds eyes on it. Eyes ready to focus on every single proportionally insignificant pitfall that it may hold, doing blatant injustice to the technological advancements that continually evolve to make fish farms more efficient, ethical and less environmentally impactful.

In 60 short years, commercial aquaculture has gone from almost nothing, to projections showing aquaculture supplying over 60% of global seafood supply by 2030.5 Norwegian salmon farming company, MOWI, holds both the 2018, and 2019 awards for the world’s most sustainable protein producer.6 Fish are able to be produced for a fraction of the environmental and economic cost they were only decades ago, new technologies now allow for growing on land based tanks in recirculating water saving systems, in-situ tech is gifting farmers new abilities to monitor fish health and minimise food wastage with next to no disturbance to fish, bi-products such as skin and bones are being repurposed to create dietary supplements, and feed producers are experimenting with insect based formulas, potentially eliminating the need for any fish meal at all.7 Make no mistake, aquaculture has tried and failed in a number of cases. But, to deny its rapid progress as an increasingly sustainable producer of global protein would be to deny truth in its most unambiguous form.

Consider other perspectives

Last, but certainly not least, was what I learned about human behaviour and how it inevitably shapes food production. For decades, it has been globally recognised that we should be eating ‘lower order’ marine species like shellfish, sardines or even seaweeds instead of larger fish like tuna, mackerel or salmon. These lower order species often have shorter life cycles, grow in greater abundance and require generally less maintenance and resources in controlled growing scenarios. It has also been recognised that as the vegan movement suggests, if everyone were to halt eating meat entirely, our overall environmental footprint would be dramatically lowered. This couldn’t be more accurate. We absolutely should all eat less or no meat. We should also absolutely eat lower order fish species with shorter life cycles that can repopulate more rapidly than larger species. Unfortunately, this doesn’t change the fact that over 3.2 billion people rely upon fish to provide over 20% of their daily protein intake.8 It doesn’t change the fact that around 2 billion people are currently employed in either livestock or fishing industries.9 It doesn’t change the fact that many cultural identities are inextricably entwined with animal protein production and consumption. So, I ask, what is to become of these people? Deciding from a place of relative privilege that a significant portion of the planets population should stop living the way they do and to take up a new livelihood (assuming there are even realistic viable alternatives) is a notion that is lazy at best, and decidedly ignorant at worst. Harsh, I know. But, it is not productive nor a solution to passionately push unrealistic goals that are achievable for the pusher, without consideration for the pushed.

It is in this sense that aquaculture can provide at the very least a partial solution, even if only temporary. Aquaculture, unlike many other forms of agriculture, actively seeks to address a global issue through unparalleled investment in science-based research exploring the most efficient farming practices possible. I am not saying aquaculture is a solution to the excessive demand we place on our oceans, but I am confident that is a step in the right direction towards alleviating at least part of the stresses placed on it by human demand and development, and all it brings. It may not be perfect, but it holds infinite promise.

What we can do

What we truly need is a fundamental change in the way we view food. It means accepting ‘ugly’ vegetables or less desirable fish species. It means coming to terms with the possibilities of eating insect-based burgers instead of that Sunday steak you look forward to. Real change takes real effort and real sacrifice to what feels familiar to us. We probably shouldn’t be producing large high end fish in farms, however, until the day comes that over half the planet wakes up and decides they actually prefer to eat shellfish and seaweed rather than salmon, the best we can realistically ask is to produce that salmon at as low of an environmental cost as possible. Aquaculture isn’t the big bad immoral money juggernaut it is touted to be. It is only facilitating what you, the consumer, demand of an ocean that can no longer provide what is asked of it.


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  1. “Global Implications of Illegal, Unreported, and Unregulated (IUU) Fishing”. Food and Agriculture Organization of the United Nations. Accessed 22 September 2019.
  2. Tom, P.D & Olin, P.G (2010). “Farmed or Wild? – Both types of salmon taste good and are good for you”. Accessed 23 September 2019.
  3. Ystrestøl, T, Synnøve Aas, T & Åsgård, T (2015). “Utilisation of feed resources in production of Atlantic salmon (Salmo salar) in Norway”. Accessed 23 September 2019.
  4. Wu, R.S.S, Lam, K.S, Mackay, D.W, Lau, T.C & Yam, V (1994). “Impact of Marin Fish Farming on Water Quality and Bottom Sediment: A Case Study in the Sub-tropical Environment”. Accessed 24 September 2019.
  5. “Fish to 2030 – Prospects for Fisheries and Aquaculture”. The World Bank. Accessed 25 September 2019.
  6. “Mowi ranked world’s most sustainable protein producer for second year”. Undercurrent News. Accessed 25 September 2019.
  7. “3 Promising Alternative Feeds for Aquaculture”. Rubicon Resources. Accessed 25 September 2019.
  8. “World’s fish consumption unsustainable, U.N. warns”. Thin Lei Win. Reuters. Accessed 26 September 2019.
  9. “Livestock”. Food and Agricultural Organisation of the United Nations. Accessed 26 September 2019.