Krill, baby, krill
Superfoods may be good for us individually. But our collective consumption of them isn’t always good for the planet. Here’s a case in point.
In recent decades, food scientists have stressed the importance of omega-3s in our diet. These fatty acids are essential for heart health, brain development and regulating inflammation. One slight problem: the human body can’t produce them. Hence the increased demand for omega-3 dietary sources, such as farmed salmon.
But where do the salmon produce these fatty acids from? Ironically, it turns out they are ‘only obtainable from the fishmeal and fish oil the salmon eat.’
As the demand for farmed salmon rises, so too does demand for feedstock. And salmon feedstock is contributing to climate change and biodiversity loss.
The feedstock consists of three main ingredients: soy, which has supply chains linked to deforestation and alleged human rights abuse; the macerated remains of battery hens; and fishmeal – a blend of whatever is easily captured or diverted, such as sardines, anchovies and krill. And they are needed at massive scale: an estimated 1.73 kg of wild fish is required to produce 1 kg of salmon.
So what exactly are krill and why are they so important? Coming from a Norwegian word meaning small fry, krill are shrimp-like crustaceans of the order Euphausiacea which thrive in the cold waters of Antarctica, growing up to 6cm in length. They can live to the age of six and may revert to juvenile forms at times of stress. To confuse predators, improve foraging efficiency and conserve energy, they form gigantic swarms covering areas as large as 100 square kilometres.
Crucially, krill are a keystone species, with an outsized impact on their ecosystem. Krill eat tiny phytoplankton (marine plants), converting them into an energy source for larger species. Indeed, krill are estimated to account for 96% of all calories consumed by seabirds and mammals on the Antarctic Peninsula. They also act as a mini carbon sink, as their faecal pellets and exoskeletons drop to the ocean floor, where the carbon they contain is trapped. In this way, they store an estimated 20 million tons of carbon annually, equivalent to the output of 35 million cars. This equates to an ecosystem service valued at between $4 billion and $46 billion, depending on the price of carbon.
A material reduction in the number of krill would therefore disrupt the food chain and have a disproportionate effect on the entire ecosystem. And yet we continue to harvest them for fishmeal, pet food and human dietary supplements.
But Krill are one of the most abundant marine species in the world, with an estimated biomass ranging from 63 million up to 400 million (for comparison, humans are around 390 million metric tons). So what’s the harm in setting an annual catch limit of 620,000 tonnes – 1% or less of estimated biomass – per season? Especially when the overseer, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), sets this limit by agreement with the 27 member countries, which include Australia, China, Japan and the European Union, and 10 acceding states, such as Canada, Finland and Greece). And, by agreement, it places scientific observers on krill harvesting vessels to collect data on fishing operations, catch composition and bycatch (other species captured by accident).
Well, the over-harvesting of krill is still a risk. In the first seven months of the 2024-25 season (which runs from December 1 to November 30), it is reported that the krill catch in Antarctica had reached 518,568 tons, about 84% of the limit, and the season had to be shut down in early August.
There are also concerns about the reliability of reported harvesting volumes. That’s partly because modern harvesting is like using a giant vacuum cleaner to take in immense quantities of sea water, which typically contains other species. So separating out the krill and accurately measuring its biomass is challenging, to say the least.
Perhaps more importantly, the data on krill harvesting only reflects areas monitored by the CCAMLR. Yet the Southern Ocean is vast and remote, and ships frequently ‘go dark’, meaning their activities are hard to monitor.
Scientists are now sounding the alarm about krill’s over-exploitation and potential ecological collapse.
Australia and the UK are pushing for a lower catch limit, recognising that less than 5% of the Southern Ocean is protected and that the broader ecosystem is under threat due to ocean warming and plastic pollution.
But can an agreement on harvest reduction be reached – let alone enforced? At Ruffer, we spend a lot of time considering the market risks of the fragmenting world order and the new cold war. Food security is but one element which may contribute to geopolitical shocks. Yet we know that the implications extend to a broad range of international organisations, treaties and frameworks. Which leads us to wonder whether it is purely coincidence that the reported volume for the 2024-2025 krill season was the highest since the collapse of the USSR. ⬤