By Brett Glencross
Sustainability is one of those words that appears to mean different things to different stakeholders. The classic Brundtland definition describes it as “meeting the needs of the present without compromising the ability of future generations to meet their own needs”, while Daly defines it as “using renewable resources, such as fish, soil and forests, no faster than the rate at which they can regenerate”. A quick Google search soon leads down a seemingly endless rabbit hole of links. Yet the question I keep returning to is simple: how do I assess whether I am making progress, and what should I measure?
For decades, a single measurement (metric) was often used for aquaculture; How many kilograms of wild fish does it take to farm one kilogram of seafood? This metric, commonly known as Fish In: Fish Out (FIFO) ratio was intended as a wake-up call. It was meant to raise the paradox of harvesting wild fish, like anchovies or blue whiting, to feed farmed carnivorous species such as Atlantic salmon or prawns. However, as global aquaculture has grown to dominate the blue food landscape, the classic FIFO model has morphed from an indicative diagnostic tool into an oversimplified, outdated and myopic lens. FIFO has subsequently evolved into various variations on that base model that proponents have argued are an improvement in each case but still had that underlying unidimensional focus (fish to feed fish). So, perhaps still not making much overall progress.
Then a landmark review published earlier this year highlighted the risks associated in such thinking by showing that although European aquaculture had dramatically increased its production between 2000 and 2020, and that it had reduced the overall amount of fish used each year, in doing so it had also massively increased its carbon footprint, water use footprint, land use footprint and so on. The outcome had not been the sustainable progress that any one was aiming for. Why did this occur, because the focus had been on a single FIFO metric, rather than a broader holistic approach to sustainable development using multiple indicators. And what needed to be assessed to make progress, what should have been measured; which is the life cycle impact assessment (LCIA) of ingredients.
Therefore, to build a resilient and equitable global food system, we need to move past basic FIFO style calculations and embrace a more nuanced, nutrient-sensitive approach that helps understand trade-offs across systems and resources. Modern environmental accounting relies on life cycle assessments (LCA) to measure LCIA indicators like Global Warming Potential (carbon footprint), Land Use, and Water Consumption. Notably, those original FIFO metrics cannot be integrated into standard LCA frameworks, making it impossible to evaluate trade-offs. Recognising these issues a recent paper titled Fish as Food or Feed? Aligning FIFO with LCA and Food System Objectives, argues that those conventional FIFO metrics are failing us. The authors note that the simple mass-balance based logic carries critical blind spots; ignoring the role of co-products and economic values. While historically, marine ingredients were sourced almost entirely from whole forage fish., today around 40 percent of global fishmeal and 55 percent of fish oil is sourced from byproducts (trimmings and offal from fish processed for human consumption). The original FIFO metrics often count these trimmings as if they were targeted wild forage catch, penalising farms that upcycle waste streams. To address these shortcomings, researchers first introduced economically allocated FIFO (eFIFO). By allocating environmental footprints based on the market value of co-products and fillets from lower-value trimmings, or weighing fish oil against fishmeal demand), eFIFO aligns marine ingredient accounting with real-world food system drivers and European PEFCR standards. However, even economic allocation leaves out the most fundamental reason humans consume seafood; essential nutrient supply. Aquatic foods are unparalleled sources of bioavailable micronutrients and long-chain omega-3 fatty acids (EPA and DHA). The newest frontier in this paradigm shift is the introduction of the economic nutrient FIFO (neFIFO), developed to measure the efficiency with which critical nutrients are retained from marine ingredients into final edible products. When evaluated through an neFIFO lens, the picture changes dramatically. Farmed Atlantic Salmon from regions like the Faroe Islands, which utilize high levels of byproduct-derived marine ingredients, act as net producers of edible EPA and DHA. They take omega-3s locked in processing trimmings that would otherwise go unused, burnt or landfilled and convert them into nutrient-dense food for human nutrition.
Aquaculture is no longer an emerging industry trying to prove its viability; it is now a pillar of global food security. Continuing to judge its reliance on marine ingredients through simplistic, 20-year-old metrics does a disservice to aquaculture, environmental science and human nutrition. It is time to retire this old thinking and embrace a more holistic approach to environmental impact assessment—one that values blue food for what it truly is: a primary engine of human nutrition, health and planetary resilience.
