In the depths of the Antarctic, there are tiny, shrimp-like organisms living in the ocean, 6 cm or 2 inches in length. Although unknown to most of the world, these tiny animals play a critical part in the care of the health of our planet. However, these tiny, seemingly insignificant animals, called “krill” are in great danger from climate change. Krill stocks have dropped by 80 % since 1970s due to various factors, mainly due to human activity. Damage to krill could have knock-on effects, since these once-omnipresent sea creatures are a key link in the oceanic food chain.

Krill are small crustaceans that feed on phytoplankton and are a key part of the food chain for numerous marine animals, including whales, seabirds, penguins, seals, squids and others. What is remarkable about krill is that they help bring down carbon in the Earth’s atmosphere, by secreting carbon-rich pellets in the deep sea.

There are more than 85 known species of krill, but most harvested is Antarctic krill or Euphausia superba. Antarctic krill plays a vital role in the Antarctic ecosystem, not only because it is a vital food source for animals, but also because the Southern Ocean is crucial for climate protection since it circulates global water currents and captures most of the carbon that humans emit.

“Krill are individually small but collectively mighty.”, said Emily Grilly, WWF’s Antarctic Conservation Manager. “That certainly applies to their ability to store carbon and help maintain stable climatic conditions that are beneficial for humanity.”

Krill is one of the most effective carbon-reducing organisms

A recent study published in Nature found that Antarctic krill sequesters around 20 million tonnes of carbon, which makes it equally efficient in carbon sinking as mangroves and marshes, which sequester approximately 24 and 13 million tonnes of carbon per year, respectively. This means that Antarctic krill is one of the world’s most important carbon-reducing creatures and krill’s carbon storing amount is estimated at a $4 -46 billion, according to the study. The monetary value depends on the price of carbon, which often uses the social cost of carbon as the estimate. Social cost of carbon is the total cost of damages that are created by one extra ton of carbon dioxide emissions, converted into dollars.

Another estimate comes from a report from World Wide Fund for Nature that valued the social cost of carbon for krill at a total of US$15.2 billion per year, which is an enormous amount compared to Antarctic krill fishery industry, whose annual worth is estimated at about US$0.25 billion, so 60 times lower.

Nevertheless, ice melting in the Antarctic, reducing number of ice algae – a primary source of food for krill, plastics in the ocean – all affect krill numbers or their capacity for carbon capture. Increasing ocean acidification due to higher carbon in the atmosphere is affecting krill eggs.

But one enormous threat to krill is human fishery. Human demand for krill boomed in the recent years, since it is being used for aquaculture, livestock and pet feed, and supplement industry, especially omega-3 supplements. Human fishery for krill has quadrupled since 2000s and in 2023 a total of 424.203 tonnes of Antarctic krill were caught in the Southern Ocean.

Consequences for animals and the ecosystem

Numerous animals in the Antarctic are now being impacted because they must compete with giant human trawlers for food. Numerous reports have documented whale deaths in the Southern Ocean, where whales searching for krill become entangled in human fishing nets. Trawlers often follow these whales to locate krill more easily, increasing the risk of such incidents.

Beyond causing animal deaths, the competition for krill is also hindering the recovery of certain whale populations. Because krill is a vital food source for many marine species, the rise in human krill harvesting is depriving these animals of adequate nourishment, putting their populations at serious risk.

The future looks bleak

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for monitoring the international waters around Antarctica and overseeing commercial krill harvesting. The countries with the largest krill catch are Norway, China, South Korea, Chile, and Ukraine, with Norway dominating the krill market with more than half of all krill caught by one Norwegian company Aker BioMarine. Ten largest krill companies in the world catch over 90% of the krill in CCAMLR-managed waters.

Despite protection efforts, recent talks have reached an impasse as China, with the support of Russia vetoed the renewal of krill fishing restrictions and both countries blocked the establishment of four new marine protected areas. They also seem to be investing millions into the krill industry.

‘“The meeting was a huge disappointment, even by the low standards that we’ve come to expect,” said Evan Bloom to AP, who led the U.S. delegation at the annual CCAMLR meetings for 15 years until 2020.’