Despite industry claims to the contrary, the global aquaculture sector has an increasing dependence on wild fish for use in feeds. Added to this, the growing consumer appetite for farmed salmon could leave coastal communities struggling to access affordable local fish like sardines and anchovies, claims a new paper published in Science Advances.
Instead of being consumed locally, these small pelagic fish are frequently caught, processed, and reduced to fishmeal and fish oil, a lot of which is used to feed farmed fish, it states, advising that these reduction fisheries account for 26% of global ocean catch.
“As the aquaculture industry grows, so does its dependence on wild fish,” said Dr Kathryn Matthews, Oceana Chief Scientist and one of the authors of the paper. “The continued rapid expansion of the sector will demand ever more fishmeal and fish oil, even as its use in feed becomes more efficient.”
According to Oceana, the authors, which also include Dr Patricia Majluf, Associate Professor with the Center for Environmental Sustainability at the Cayetano Heredia University and former Oceana Vice President in Peru; Dr Daniel Pauly, Oceana Board Member, fisheries scientist, and principal investigator at Sea Around Us; Dr Daniel Skerritt, Oceana Senior Analyst; and Dr Maria Lourdes Palomares, Senior Scientist and Research Unit Manager at Sea Around Us, debunk the industry’s use of the Fish-in-Fish-out (FIFO) ratio — the standard metric used to quantify how much wild fish is used to produce farmed fish.
The FIFO ratio is often used as an indicator of the impact of aquaculture on wild fish stocks.
The ocean conservation organisation said the paper’s authors showcase misleading practices about the FIFO ratio, such as averaging fishmeal and fish oil inputs of carnivores and herbivores together to conceal the high feed requirements of carnivorous species. This, it said, lowers the FIFO ratio, reaffirming the aquaculture industry’s claim that its dependence on fish oil and fishmeal is decreasing. But fish oil, especially, is a limited commodity that is increasingly in demand by salmon farms, which now supply 70% of all salmon consumed worldwide. In 2020, farmed Atlantic salmon alone accounted for 60% of fish oil usage, the authors calculated.
“The salmon industry is a not a food production system — it’s a food reduction system. It benefits the few who can afford it but reduces access to nutritious fish for those who need it the most,” Matthews said.
Oceana gave the example of processing plants in West Africa, which it said are exploiting vast amounts of small pelagic, highly nutritious fish, mostly sardinella, to produce fishmeal and fish oil for export.
“This is an equity issue — it puts local fishmongers at an unfair disadvantage because they cannot compete with the prices the plants are willing to pay for this global commodity,” Skerritt said.
Additionally, the authors anticipate a turbulent future ahead for fishmeal and fish oil production. They note that climate change is impacting fish populations around the world, including the main source of fishmeal and fish oil – the Peruvian anchoveta.
Like many others, this species in warmer waters contains less fish oil. Moreover, continued poor management of these fisheries allows for ever higher catches of juveniles, which also contain less oil, they said.
“Combined, these factors are driving feed manufacturers to look elsewhere for additional oil, including in fisheries which typically provide fish for direct human consumption, like mackerel,” Majluf said.
The authors said that for these reasons, they are urging the industry to operationalise substitutes for fishmeal and especially fish oil in aquaculture fish feeds.
