Pisciculture (the farming of fish) is a growing subset of aquaculture, which now produces the majority of the global fish supply. Farming of aquatic species increased rapidly beginning in the 1980s, emphasizing the production of high-value carnivorous and omnivorous finfish and crustaceans. As human demand for seafood has risen, aquaculture operations have become increasingly industrialized, generating concern from animal advocates and food system researchers.
Salmon are among the most-farmed aquatic species worldwide, with farmed salmon accounting for approximately 70% of the global salmon market. Salmon farming is a lucrative and growing industry for the leading multinational production companies and wealthy producer nations of the Global North. However, this profit comes at the price of harm to the aquatic ecosystems of lower-income nations and coastal populations of the Global South, many of which traditionally depend on artisanal fishing for nutrition. New research by Feedback Global indicates that salmon farming is a key contributor to global food insecurity and inequity.
Without significant changes to production and consumption, global seafood demand could double between 2021 and 2050. While fisheries agencies and other proponents often praise aquaculture’s potential to be a sustainable alternative to the overfishing of wild species, aquaculture’s increasing emphasis on carnivorous aquatic animals such as salmon generates a significant hidden impact on wild fish populations.
Aquaculture—particularly salmon aquaculture—presents serious environmental, ethical, and global equity concerns and potential tradeoffs. Addressing these challenges will require changing how and to what degree salmon and other aquatic species are farmed and questioning the global food system’s reliance on industrial animal farming.
The Salmon Industry
In 2020, aquaculture produced more than 2.6 million tons of farm-raised salmon. Worldwide, production of Atlantic salmon—the most highly-farmed species of salmon—has risen steadily nearly every year since 2000. Atlantic salmon alone accounted for 32.6% of finfish aquaculture production in 2020, and farmed salmon stocks are expected to continue growing.
In 2015, five nations produced 95.6% of the world’s farmed salmon, with more than half the global supply being produced by Norway, Chile, Scotland, Canada, and the Faroe Islands. Salmon was Norway’s leading seafood export in 2021, accounting for $9.2 billion of a total $13.7 billion.
Impacts on Wild Salmon and Aquatic Ecosystems
Salmon farming began, in part, to compensate for the decline of wild salmon, whose populations decreased by over 50% between 1983–2016 due to the combined effects of human-built dams, pollution, overfishing, and climate change. As salmon production has increased in response to rising demand, the $20 billion salmon farming industry has been criticized for increasing negative impacts on wild fish and coastal ecosystems.
The salmon farming process takes up to three years. Farmed salmon start their lives in hatcheries and are raised in freshwater enclosures before being transferred to open ocean net pens, where they remain until harvest. Salmon in net pens are intensely crowded, sometimes numbering in the hundreds of thousands, and subjected to harmful conditions, including poor water quality, rough handling, and the aggression and cannibalism common among overcrowded fish. High stocking density of farmed fish also facilitates the spread of disease within and outside of pens. Viruses, sea lice infestations, and other illnesses, along with harsh treatments for such health conditions, increasingly result in mass mortality among farmed salmon. Investigations reveal that as many as one-quarter of Scottish farmed salmon die during production. Intensive aquaculture operations borrow from the playbook of terrestrial industrial animal agriculture by administering routine antibiotics to curb disease among farmed salmon, with the side effect of encouraging the development of antibiotic-resistant infections. Furthermore, antibiotics fed to captive fish can remain in food products, potentially contributing to the crisis of antimicrobial resistance, which already kills approximately 1.27 million individuals annually worldwide.
Ocean and freshwater net pens allow direct contact with circulating open water, permitting a free flow of contaminants such as feces, pharmaceuticals, and uneaten food that can harm wild aquatic life. Additionally, wild salmon often migrate through waters occupied by salmon farms, where they can be exposed to concentrated residues of feed, antibiotics, and feces. Farmed fish also occasionally escape from pens, threatening local ecosystems. In February 2021, researchers connected salmon farming to approximately $47 billion in costs from pollution, damage to wild fish populations, and contributions to climate change.
While itself a driver of climate change, salmon aquaculture is also particularly vulnerable to the effects of a changing climate. As climate change intensifies, the cool waters ideal for salmon farms are becoming more difficult to find. Furthermore, salmon farming may also exacerbate climate change, generating associated greenhouse gas (GHG) emissions similar to emissions from poultry production. Detailed GHG inventory analysis of Scottish salmon farms reveals that between two-thirds and three-quarters of salmon aquaculture’s emissions come from the production of feed used to support farmed fish.
Researchers Find Salmon Farming “Inefficient and Inequitable”
A March, 2022 study by Feedback Global reveals the inequity of harvesting millions of tons of wild fish from the Global South to feed farmed fish produced and largely consumed by North America and Europe. The authors conclude that salmon farming is an inefficient way to produce global protein for human consumption and highly problematic for exacerbating resource inequality in the global food system.
Salmon are carnivorous. Their mass production on fish farms creates a burden on populations of wild pelagic fish, including anchovy, herring, sardine, and mackerel that are harvested as feed for farmed salmon. It takes slightly As much as 46% of the global populations of these small pelagic fish are estimated to be overfished. Analysis by Faunalytics underscores that fish farming relies on overfishing rather than offering a solution to it, estimating that 662 billion individual wild fish are caught each year for production of fishmeal and fish oil (FMFO) used in aquaculture.
According to Lia ní Aodha of Feedback Global, “Aquaculture is often presented as a climate-friendly protein alternative, a way to protect fish stocks and address global food insecurity. The type of aquaculture matters, however. And the reality is that over the past four decades, the farming of high-value fed species (e.g. salmon) reliant on wild fish as feed has outpaced the development of other forms of aquaculture.”
“Reflecting—rather than mitigating—the same inefficiencies and inequities of the broader food system, the nutrient-rich fish used to feed fish like farmed salmon are increasingly sourced from food-insecure and fish-dependent regions in the Global South. Intensively reared salmon are then sold to consumers in high-income markets in Europe, North America, and parts of Asia,” she adds. Feedback Global’s study indicates that millions of tons of wild fish could remain in the oceans of the Global South if not harvested as feed for carnivorous farmed fish such as salmon—a practice researchers say is exacerbating inequitable food access worldwide.
Moreover, Feedback Global’s examination of salmon aquaculture suggests that the use of wild-caught fish to feed farmed salmon represents an inefficient waste of nutrients in the global food system. Their analysis finds that, of the more than 20 million tons of wild-caught fish used to feed farmed fish and farmed animals worldwide, over 90% are considered “food-grade species” fit for direct human consumption, yet the nutrients from these fish are largely lost during salmon farming. Feedback Global reports that only 1–49% of “essential dietary minerals and fatty acids” from wild forage fish remain in farmed salmon meat. Similar research has found that farmed salmon provide four times less protein than the amount they consume during production. In the context of predicted continued growth in aquaculture, this resource inefficiency demands the same scrutiny as the resource-intensive use of nutritious food-grade crops to feed terrestrial farmed animals.
Beyond nutrient efficiency, the global resource equity implications of farmed salmon production are staggering. The same species of small pelagic fish harvested to produce FMFO to feed farmed salmon for consumption in the Global North are also considered a crucial food source for marine animals, birds, and people worldwide, with special importance for nutritionally vulnerable coastal populations of the South Pacific and Africa. In many coastal nations and communities struggling with food access in the deeply inequitable industrial food system, traditional small-scale subsistence fishing is vital to ensuring local food security. An estimated 90–95% of catch from small-scale fisheries is consumed on a local level, and the livelihoods of at least 492 million people worldwide rely on these fisheries. While farming of many other aquatic species contributes primarily to local rather than export markets, increasing salmon aquaculture for high-income markets of the Global North poses a direct threat to equitable food access worldwide.
Salmon Aquaculture Deepens Historical Patterns of Inequitable Resource Extraction
Feedback Global cites examples of nations particularly impacted by aquaculture’s use of FMFO, including Peru and the West African nations of Senegal, Mauritania, Ghana, and The Gambia.
Peru is the world’s top producer of fishmeal, largely made from anchoveta. While direct local consumption of anchoveta is limited but increasing, the regional anchoveta catch is dominated by international demand for FMFO. In 2019, the country exported more than $1.5 billion in terrestrial animal feed and pellets produced from fishmeal, along with $420 million of fish oil products sent to markets in Europe and the United States after processing in China. In 2020, an investigation by Oceana showed that some companies in Peru claiming to use anchoveta for direct human consumption instead diverted them to fishmeal factories. In the first half of 2022, Peru’s exports of FMFO exceeded $1 billion, and they are China’s leading supplier of fishmeal.
In Western Africa, against the backdrop of worsening hunger in sub-Saharan Africa, the presence of fishmeal factories is growing, placing increasing strain on local food webs and economies. A 2019 Greenpeace report warned that the region’s growing FMFO industry is a threat to local food access in Mauritania, Senegal, and The Gambia. A subsequent report by Changing Markets Foundation and Greenpeace in 2021 echoed previous conclusions, estimating that if not diverted to produce FMFO for European and Asian markets, the forage fish extracted from West African waters could feed more than 33 million food-insecure people in this region.
Senegal may be particularly impacted by the harvest of small pelagic fish from its waters by overseas farmed fish producers. The Senegalese people consume the majority of their protein from fish, and research has shown that local artisanal fishers’ profits declined significantly from 1993–2013 due to the presence of commercial fishing fleets. Fish consumption in Senegal declined by 30% between 2009–2018 as a result of the increasing export of small pelagic fish and a growing number of non-food uses for fish catch. In Ghana, where local populations are heavily dependent on fishing for protein, illegal, undeclared, and unregulated fishing of small pelagic species for the commercial fleet presents an escalating threat to food access.
The Food and Agriculture Organization of the United Nations (FAO) reports that in Senegal and neighboring nations, an “increase in [fish-derived ingredient] FDI production that may depend on edible fish will worsen the already critical situation of fish availability and affordability.”
To alleviate pressure on wild fish populations and address the serious efficiency and equity concerns of salmon farming, Feedback Global emphasizes the importance of changing how farmed salmon are fed—for example, by shifting to feeding farmed fish on waste streams from the commercial fishing industry rather than feeding them wild-caught food-grade forage fish. While potentially beneficial, the impact of this change is likely limited compared to the possible benefits that could be realized by shifting away from intensive salmon aquaculture altogether.
Aquaculture is increasingly substituting plant-based feed ingredients in place of FMFO for farmed fish. A study of Norwegian salmon farming reveals that marine protein and fat sources in farmed fish feed have fallen from 89% of overall feed composition in 1990 to just 22% in 2020, with the difference now made up by the increasing use of vegetable lipids and proteins. The growth of plant-based feed substitutes, along with efficiency gains in the extraction and use of FMFO, has allowed the broader aquaculture industry to reduce its reliance on FMFO, but large quantities of wild fish are still needed to produce farmed salmon.
Polling indicates that consumers are increasingly concerned about the treatment of animals raised for food. For some consumers, plant-based seafood alternatives represent a feasible opportunity to reduce or eliminate fish consumption. Despite the negative impacts of the COVID-19 pandemic on food supply chains, the plant-based alternative seafood market was valued globally at $42.1 million in 2021 and is estimated to reach a value of $1.3 billion by 2031.
Cultivated seafood could soon present another alternative option for some consumers. These products are grown using cells from living fish, without requiring any animal slaughter. Startups worldwide are making progress with research and development. If these products can gain widespread regulatory approval and significantly reduce production costs, cultivated seafood may provide a viable challenge to exploitative patterns of global aquaculture.
While there are steps the existing aquaculture industry can take to reduce its impact on wild fish stocks, improve its resource efficiency, and lessen its contributions to global food system inequity, fish farming still relies on the exploitation of billions of aquatic animals as food. In the presence of increasingly viable alternatives, the continued exploitation of carnivorous aquatic species such as salmon for the benefit of higher-income nations and consumers presents serious ethical concerns. These concerns can only be fully addressed by meaningful systemic change that replaces industrial aquaculture with inclusive, equitable, environmentally friendly plant-based food production.
A version of this post appeared previously at Sentient Media on March 8, 2022.
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