Guest Piece by Manon Theodoly

Tonnes of dead fish dumped onto the shores of Chiloé Island — from news.mongabay.com

The demand for seafood products has grown at unprecedented rates in the last fifty years. Each person eats on average 19.2kg of fish per year, around twice as much as 50 years ago. This amount is projected to continue rising in the future. Over the same time period, there has been a 39% decrease in recorded marine species, a number which will only grow if current practices are not altered. A shift towards aquaculture has been the global response to the unmanageable pressure imposed on wild fish stocks. However, contrary to popular belief aquaculture has its own downfalls for the marine ecosystem, as increasingly intensive practices have equally worrying environmental consequences.

Graphs showing the rise in consumption per capita — from Our World in Data

Why Is Demand Increasing?

The obvious answer is population growth. However, since 1961, annual global growth in fish consumption has been twice as high as population growth, so it cannot be the only factor. A large influence on growth per capita is rising consumer awareness of the health benefits of seafood touted by doctors and nutritionists, coupled with a general trend in favour of ‘healthy eating’. Urbanisation is another factor, the urban population has increased by 2/3 to make up 68% of the population by 2050. Urban dwellers typically have more disposable income to spend on animal proteins. Furthermore, an increased population density and evolved infrastructure allow for more efficient storage, distribution, and marketing, making fish widely available. Finally, growth in demand is linked to increased trade liberalisation, combined with advances in transportation technology. This lengthens the supply chain so the product can be fished in one country, processed in another and consumed in yet another, all of which facilitates access to a wider range of seafood products.

The Problem with Maximum Sustainable Yield (MSY)

“Simply put, we are running out of fish… maybe centuries ago we could live off hunting for our food but we can’t live off hunting today and fishing is hunting. The notion of hunting in the 21st century to feed 10 billion people is absurd”
Daniel Pauly, professor at the University of British Columbia

Growing demand leads to the intensification of fishing practices, which threatens global fish stocks. At present, 1/3 of marine fish stocks are being fished at biologically unsustainable levels (meaning that the levels fished compromise the reproductive capacity of the stock). Rebuilding these stocks requires time, 2–3 times the species’ lifespan, so it seems unlikely that these stocks will be rebuilt in the near future. In the North-East Atlantic, 39% of stocks are classified as overfished, whereas in the Mediterranean sea, data for 85 stocks suggests that 88% of these are overfished.

Graph from eu.oceana.org

X-axis — biomass where the growth of population is at its greatest

Y-axis — fishing effort at maximum sustainable yield (MSY)

The sustainability of the industry is measured by maximum sustainable yield (MSY), meaning the maximum level at which a stock can be exploited without long-term depletion. Problems arise when the environmental impact of a practice is measured bycatch per unit of effort. Calculating what has been caught and using this to estimate what is left does not consider the ecosystem as a whole. Focusing on a single species as an entity separate from its environment neglects the decline of aquatic species dependent on these fish sources, as well as the impact of trawling and subsequent by-catch on species not covered for any assessment. Furthermore, MSY does not consider the complexity of shared stocks. Many species migrate, straddling national European Economic Zones (EEZs), to areas beyond national jurisdiction. Migratory species will move to different locations at different stages of their life cycle, but because they are considered a single unit, fishing in any area will affect the whole stock. Additionally, methods of determining stock status are both expensive and technologically demanding, thus, not a viable option for developing countries. The annual proportion of non-reporting countries grew to 29% in 2017, rendering MSY data reliant on national reports unreliable. MSY has contributed to the devastating collapse of many fisheries, such as the Northern cod collapse, and is considered amongst many biologists as dangerous and misused.

Damaging Practices

The aftermath of dynamite fishing — from coralreefimagebank.com

MSY as a management technique has many shortcomings and has a worrying impact on marine biodiversity. However, the physical practices involved with wild fishing amplify this decline.

These practices include trawling, where a boat pulls a fishing net through the water, and dredging, where a scallop dredge is dragged along the seafloor collecting crabs, clams, and other bottom-dwelling species. The main problem with trawling involves the vast quantities of bycatch discarded: an estimated 38.5 million tonnes every year. This includes undersized fish and endangered species such as sharks, dolphins, turtles, and whales. For a single 400g frozen cod fillet to reach a household, around 700m2 of seafloor is swept by trawls, and 50g of under-sized cod and other marine species are discarded. Dredging essentially involves scooping out large quantities of the ocean floor, destroying corals, vegetation, and countless other delicate habitats in the process. It is estimated to cause 1–3 times more seafloor damage than the oil and gas industry.

The practices involved in the processing and distribution of marine products are also damaging, primarily in terms of the vast quantities of greenhouse gas emitted during transportation. However, the loss and wastage between landing and consumption are equally detrimental, estimated to account for 27% of landed fish.

Moreover, illegal fishing continues to be a worrying issue. It is estimated that 11–26 million tonnes of fish are caught illegally each year, corresponding to at least 15% of the world’s catches. This is problematic as fishing methods are unregulated and landed fish are undocumented, magnifying the decline of marine stocks.

Possibly, the most pressing issue at present is the sustainability divide between developed and developing countries. More than 50% of fish imports are from developing countries. However, fishing practices are generally less sustainable in developing countries. This is because the allocation of resources for monitoring and catch data collection is often not a priority in countries with more pressing social issues to address. The result of this is a limited management and governance capacity, rendering damaging or illegal practices almost impossible to eradicate.

A combination of poor management and harmful fishing methods has led to a devastating decline in marine species. To counteract rising prices, caused by a combination of growth in demand and dwindling fish populations, aquaculture has grown exponentially in the last 50 years. Aquaculture is the rearing of aquatic species for human consumption. It ranges from extensive systems where minimal effort is required, to intensive systems where high densities of fish are raised in a controlled environment. Fish farming made up 54% of world fish consumption in 2016 and grows annually by 5.8%.

Is Aquaculture the Solution?

Farmed carp — from environment.com

Aquaculture is seen by many as a means of relieving pressure on wild stocks. A brief investigation into the methods involved in producing farmed fish suggests that this is not the case. The paradox is that aquaculture is at once a possible solution and a contributing factor to the collapse of global fish stocks. This is because nearly 70% of aquaculture relies on wild fisheries for feed. Many intensive aquaculture systems use 2–5 times more fish protein to feed farmed species than is supplied by the product. In fact, 2/3 of fish meal and fish oil (FMFO) used in aquaculture systems is produced from wild-caught fish. This means that 15 of the 90 million tonnes of wild-caught fish captured globally is reduced to fish feed. Furthermore, only small volumes of the fish being made into feed are from MSC certified fisheries, suggesting that these are overexploited and overfished. The problem is exacerbated as the expansion of aquaculture farms is fuelled without significant change in reliance on marine ingredients. For example, the Scottish farmed Salmon Industry, whose success depends on the high-omega 3 content sourced from wild feed, plans to expand by 100–165% by 2030. This would require an increase in use of wild fish from around 460,000 tonnes to 7,070,000 tonnes per year, putting an unmanageable strain on a finite resource.

Problems arise when aquaculture, a private sector activity, produces more fish than capture fisheries. Intensive farming increases the risk of spreading pathogens to wild populations, such as the Yellowhead virus which caused catastrophic losses for wild shrimp populations in Texas. This shows how the introduction of a foreign species can lead to the dramatic decline of its native counterpart, which might not be as resilient to the virus. Studies have connected intensive farming to pathogen virulence, meaning the ability of a pathogen to infect a host, as high densities of homogeneous fish enhance transmission opportunities. Water pollution from faeces and waste food contributes to this problem, leading to eutrophication which worsens the spread of disease. Furthermore, genetically modified escapees can hybridise with and alter the genetic makeup of wild populations. This is particularly problematic for migratory species, which are genetically adapted to their natal spawning grounds.

Furthermore, aquaculture requires energy for aeration, water changing, and transportation. It also requires natural sources of water, changing entire landscapes and ecosystems. Hundreds of thousands of hectares of mangroves and coastal wetlands have been transformed into milkfish and shrimp ponds to cater to this demand. Mangroves, one of the richest ecosystems on earth and crucial for shoreline protection, are destroyed at 5 times the rate of rainforests, with 30% of mangrove deforestation across South East Asia attributed to shrimp farming.

As fish stocks continue to decline, we have been forced to develop alternative methods of providing for growing demand. At present, the only solution has been a move towards aquaculture, whose growth has promised to relieve pressure on wild stocks. However, the rapid expansion of the fish farming industry carries worrying consequences of its own. Unless more sustainable practices can be developed, it will not be a viable alternative, and a crisis will continue to loom large on the horizon.

Finding a Solution: Could Synthetic Fish Be the Answer?

Synthetic salmon — from wildtypefoods.com

The difficulty with abandoning traditional fishing methods lies in the livelihoods affected by the transition. 60 million people make a living from fishing and aquaculture worldwide, a large proportion of which are in developing economies. In order for these people to continue making their livelihoods in the fishing industry, it is important to develop more sustainable practices.

In the case of wild fisheries, this could mean improving cooperation between developed and developing economies in terms of policy coordination, financial aid, and the deployment of advanced technologies. More unified policies would avoid the tragedy of the commons, where some countries fish sustainably whilst others act according to self-interest, depleting the resource. Financial aid would improve processing and distribution infrastructure and services, which currently result in high post-harvest losses. The development of advanced technologies would provide a cheaper and more accessible means of collecting data, improving MSY estimations and therefore providing more accurate calculations of which stocks are being overfished.

The scope for ensuring adequate sustainability is much broader when it comes to aquaculture. Integrating production systems, which optimize the use of natural resources by cultivating different species alongside each other, could reduce the risk of nutrient pollution. Bivalves, such as mussels, oysters, and scallops have the potential to restore marine ecosystems, as they do not require feed and can be grown in the wastewater from intensive systems. Establishing fines could minimize the number of escapees and enforcing stricter biosafety measures for imported stocks would reduce the risk of disease. Much research has gone into finding different food sources to reduce the use of wild-caught fish. Algae oil is a promising source if it can be made widely available. Another option is for trimmings and by-products to be recycled back into feed. Fish meal could even be replaced with insect meal. Taking this idea even further, the insects could be fed with food waste, keeping leftovers from human consumption within the supply chain.

However, the above solutions are limited in their ability to completely eradicate the problems associated with extracting food from a wild ecosystem. In striving towards a fully sustainable industry, perhaps it is time to move away from catching or farming fish altogether. This can now be done through the cultivation of synthetic fish. This essentially means extracting fish stem cells (which can grow into a number of other cells) and growing them in a lab to form muscle cells, with the eventual goal of making commercial quantities of edible fish. At present, a number of start-ups are experimenting with this idea. Wild Type in San Francisco focuses on salmon, Shiok Meats in Singapore specialises in crustaceans and shrimp, while Finless Foods is particularly invested in growing affordable tuna.

Diagram explaining cell culturing — from frontiersin.org

Synthetic fish is a healthier alternative, free from hormones, antibiotics, mercury, and microparticles of plastic. A common misconception is that wild fish is more nutritious due to its diverse diet. However, the nutrients in fish are essentially the contents of its cells, which can be replicated in a lab without the pollutants commonly found in wild-caught fish. Synthetic fish is also cruelty-free, as animal cells can be obtained harmlessly by biopsy of a living being. Moreover, lab-grown fish avoids the production of inedible excess tissues such as bones and scales which are discarded and pollute the environment. It also reduces fossil fuel emissions, considering it can be produced in urban centres and doesn’t require fleets or shipping. Additionally, cultures only require weeks to months to generate functional food, while genetically modified (GM) salmon still requires 18 months to grow to market size. This shorter cycle means that high valued species could eventually be produced for affordable prices, a solution to the current lack of resources and subsequent famine in developing countries.

Thus far, the field of lab-grown beef has been widely successful, with investments growing by 85% in 2018 alone, indicating its growing popularity. Cultured fish has the potential to be even more fruitful, due to fish cells being far better suited to in vitro conditions. Keeping mammalian cells alive in the low-oxygen conditions of the bioreactor requires high levels of energy, whereas fish cells are far more tolerant to hypoxia. Another problem with mammalian cell cultures is that their PH range must be very carefully controlled, as they produce lactic acid in anaerobic conditions, which accumulates and leads to cell death. Due to the high intracellular buffering capacity of fish cells (their ability to maintain a neutral PH in the presence of metabolic end products such as lactic acid), they are far more resilient and easier to culture. Finally, fish cells are able to grow at lower temperatures. This is because species living near the earth’s poles have adapted antifreeze defense systems, meaning they produce more antioxidants. As a result, fewer greenhouse gas emissions are produced in an attempt to maintain constant temperatures within the bioreactor.

However, synthetic fish encounters similar problems to those initially encountered by its mammalian counterpart. More research is required before it can reach the market with competitive prices. A survey of potential customers in the US suggests that while most respondents were willing to try in-vitro meats, only a third were willing to eat it regularly as a replacement for farmed alternatives. The main concerns raised were an anticipated high price, limited taste, and appeal and that the product was ‘unnatural’. While education can help break the latter two misconceptions, price is a large obstacle. Synthetic fish meat is currently not competitively priced or affordable enough to scale up production. However, the price of lab-grown meat is projected to plummet from $280,000 to $10 per patty by 2021, a result of it being scaled up. The success of cultured beef suggests that with further research this obstacle will be surmounted. This will be achieved primarily through finding an alternative to the commonly used foetal bovine serum used to kick-start cell division, which is both expensive and contradictory to the notion of being environmentally sustainable. Finless Foods is currently researching which growth factors are most important for the growth of fish cells and how these proteins could be grown in a lab. This may involve inserting fish DNA into yeast which can replicate and grow these proteins, similar to how insulin is produced to treat diabetes. Replacing bovine collagen would also allow cells to form a fibre, moving from the currently produced ground products to actual fillets of fish.

The market reaction towards cultured meat was originally negative, coining it ‘Frankenmeat’ and consumers were sceptical of its potential as a farmed meat alternative. What the synthetic fish industry can learn from its unprecedented growth in recent years is that environmentally sustainable alternatives sell themselves, and it is simply a matter of refining the technology.

Finally, data from monitored fish stocks tells us that numbers continue to decline. What it doesn’t show us is the devastating impact on the ecosystem as a whole. Until vast quantities of fish stop being taken from the sea, marine biodiversity will continue to suffer catastrophic losses. This matters not only because of the subsequent consequences for the natural environment, but also because it threatens vital food sources for local communities, and threatens to render fish a product for the wealthiest in society. Aquaculture continues to rely on wild feed, so at present, a total shift away from fishing seems impossible. Cultured fish is a promising solution, provided it can be scaled up to be competitively priced. Until this can be made possible, it is crucial that individuals, communities, and governments work together towards more sustainable fishing and farming practices.