Antarctic krill are small, shrimp-like marine crustaceans (Euphausia superba). They feed on plankton and are the main food source for larger marine animals. The word “krill” comes from the Norwegian word “kril” meaning the small fry of fish.

Why are they so important in Antarctica?

In the Antarctic, they are the key species upon which the entire Southern Ocean ecosystem relies. Although only the size of a paperclip, penguins, whales and seals all rely them as their primary food source. They also play a crucial role in regulating the climate by storing carbon. One study found krill can remove up to 12bn tonnes of carbon a year from the atmosphere

They are fished in vast quantities by industrial trawlers across the Southern Ocean and turned into food for pets and farmed fish, as well as omega-3 dietary supplements.

Last year, about 500,000 tonnes of krill were trawled in the Antarctic. Norway took 67.2% of the total krill catch in 2023; followed by China, at 17.1%; South Korea, with 8.4%; Chile, with 4.4%; and Ukraine taking 2.8%.

Are they under threat?

Conservationists and scientists have long warned that krill are under increasing threat from overfishing and climate change.

A recent study by Norwegian and German scientists, using acoustic recordings to identify areas of overlap, found krill ships and Antarctic predators follow the same krill swarms. There was no point in the year where fishing does not affect the feeding of marine life, they said.

The research ship RRS Sir David Attenborough in Antarctica. The vessel’s namesake has warned that trawling for krill ‘might be removing the foundation of an entire ecosystem’. Photograph: BAS

In his film Ocean, which showed krill trawlers next to Antarctic whales, David Attenborough voiced his concerns: “Some claim this is sustainable but we might be removing the foundation of an entire ecosystem.”

Is there any official oversight of krill fishing?

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is an international body set up in the 1980s, partly in response to concerns over the impacts of krill fishing on wildlife. As part of the Antarctic Treaty System, its objective is to take a precautionary, ecosystem-based approach to fisheries management.

Made up of 26 member countries and the EU, the commission meets each year to make decisions on fishing catches and the designation of marine protected areas (MPAs). In 2009, all members agreed to set up a network of MPAs in the Southern Ocean by 2012.

Since then, however, only two MPAs have been established – the South Orkney Islands and the Ross Sea – despite member states’ proposals. This has raised questions about the body’s effectiveness.

The commission, which operates on a consensual basis, has been in diplomatic deadlock for years, with Russia and China repeatedly blocking the setting up of MPAs.

Who is putting pressure on CCAMLR?

A coalition of scientists, conservation organisations, environmental activists and others have called on CCAMLR to ensure it implements its conservation mandate and close the Southern Ocean to krill fishing.

Launching their campaign at the UN Ocean conference in France earlier this year, they warned that the continued exploitation of krill would lead to ecological collapse. The actor Benedict Cumberbatch and veteran oceanographer Sylvia Earle are among the campaign’s supporters.

The actor and campaigner Benedict Cumberbatch has said: ‘Protecting the Southern Ocean isn’t optional – it’s essential for the health of our planet.’ Photograph: Kate Green/Getty/BFIWhat is happening at CCAMLR this year?

This year, for the first time, the number of krill trawled in Antarctic waters reached what scientists believe is an unsustainable level.

Despite this, some countries are seeking to vastly increase the catch limit in the ecologically sensitive Antarctic Peninsula. Any proposal to do so could exceed a precautionary limit set by scientists.