As Antarctic waters warm due to climate change, krill numbers are declining, stressing wildlife that rely on the small crustaceans at the bottom of the food chain.

Two huge fishing vessels make their way through the icy waters of the Southern Ocean, passing among a pod of dozens of whales while slowly hauling on board bulging nets hundreds of meters long. The scene recalls a bygone era before commercial whaling was banned. Now, however, the vessels are not fishing whales but whale food: swarms of Antarctic krill (Euphausia superba), a small shrimp-like crustacean at the base of the Southern Ocean food chain.

“In the 20th century they used to follow large swarms of krill to help locate whales,” Matthew Savoca, a research scientist at the Hopkins Marine Station of Stanford University, told Mongabay. “And now potentially the krill fishery is doing the opposite, using whales to find krill.”

The scene above was filmed in March off the South Orkney Islands in Antarctica during a joint voyage by the nongovernmental organizations Sea Shepherd Global and Tasmania-based Bob Brown Foundation. The footage showed fishing trawlers moving through a pod of about 100 fin whales (Balaenoptera physalus), animals listed as vulnerable by the IUCN that in the Southern Ocean feed almost exclusively on krill. The video proved a “huge and growing conflict [for krill] between whales and supertrawlers in the Antarctic,” a Bob Brown Foundation media release stated.

In February, Savoca co-authored a report in the journal Ecology documenting a similar case that his co-authors had filmed a year earlier near Coronation Island, the largest of the South Orkneys. On that occasion, scientists encountered four trawlers fishing in the presence of what they described as a “remarkably large aggregation of foraging fin whales” numbering about 1,000 animals.

“This has been happening for years,” Savoca said. It’s just what we were able to record. The point of the videos is alerting the scientific world that this is happening and will continue to happen, unless we change our policy about how we fish.”

Different interests in krill

Antarctic krill sustains various populations of wildlife, especially penguins, seabirds, seals and whales. Yet in recent years, international interest in krill fishing significantly increased. Krill serves as an ingredient in aquaculture feed and, to a lesser extent, in pet foods and omega-3 supplements for human use.

Although there is uncertainty and debate about the actual amount of krill in the Southern Ocean, several studies have documented a reduction in krill numbers, mainly related to climate change, and still others have shown that regionally reduced krill availability, including due to krill fishing, is affecting Antarctic penguin populations. In late March, a study published in Nature provided more evidence that less-available krill may be responsible for “dramatic decreases” observed in populations of chinstrap penguins (Pygoscelis antarcticus) across the Antarctic Peninsula.

“On years of less krill, they have to increase the foraging effort, dive slightly deeper, forage for longer, do slightly larger trips,” Lucas Krüger, a researcher with the Chilean Antarctic Institute and a co-author of the study, told Mongabay. “Even doing that, it seems that they were not able to feed the chicks, so the breeding success was comparatively lower in the years of low krill density.”

A sector of the krill industry also acknowledges the potential impact of krill fishing on penguin populations: In 2018 the Association of Responsible Krill Harvesting Companies (ARK), a trade group based in Tasmania that brings together almost all the companies operating krill vessels in Antarctica, launched voluntary measures to reduce fishing “in buffer zones around key penguin colonies in the Antarctic Peninsula and the South Shetland Islands during their breeding season.”

Industry and international organizations have been paying less attention to the fishery’s potential impact on whales because some whale populations are growing.

A recent survey of fin whales found evidence of high densities, re-establishment of historical behaviors and the return to ancestral feeding grounds, indicating a recovering population,” ARK wrote in a post on its website replying to the NGOs’ video. “The vessels are licensed, operating in accordance with all CCAMLR Conservation Measures and all have scientific observers on board,” ARK stated, referring to the Commission for the Conservation of Antarctic Marine Living Resources, an intergovernmental body established in 1982 to preserve Antarctic marine life in response to increasing commercial interest in Antarctic krill.

“We are very happy that whale populations are recovering in Antarctica,” Javier Arata, ARK’s executive officer, told Mongabay, adding that in recent years, “we have seen a lot of whales; it’s a good sign that the CCAMLR system is functioning to allow them to recover.”

According to Savoca, there are no regulations prohibiting fishing for krill near whale pods, and this is reason for concern. “It’s a competition not just for krill, but for these specific ways in which krill get together,” he said, referring to the huge krill swarms that fishers and whales both target. “They are super important to the whales, because that may be the best meal they have all year, and without regulation the fishery will go for that. Economically it makes the most sense,” he said.

While there are no rules preventing krill fishing vessels from accidentally killing whales, and at least three such deaths occurred in the 2021-22 season alone, the incidence is low enough that Savoca and others are mainly concerned about the competition for krill.

A warehouse with bags of krill meal.

Which whale recovery?

But the krill fishing industry and the scientists calling for tighter regulation disagree as to whether whales really are recovering in the Southern Ocean.

According to Helena Herr, a researcher at the Institute of Marine Ecosystem and Fishery Science of the University of Hamburg, some whale populations are recovering but are a long way from returning to their original levels. “Only 50 years ago there were only 1-2 percent of the original population of whales left,” she told Mongabay. “All of the large whales were almost removed from the Southern Ocean ecosystem.”

Only the population of humpback whales (Megaptera novaeangliae) is really recovering in Antarctica, Herr said, while a recovery of fin whales “is only just beginning” and blue whales (Balaenoptera musculus) “are not recovering” in Antarctica at all. These species are listed as least concern, vulnerable and endangered, respectively, by the IUCN. In the Southern Ocean, all three feed primarily or almost exclusively on krill.

“At least as a precautionary measure, we cannot go and target the feeding grounds to deplete the krill of populations that are recovering or are still not recovering,” Herr said.

In March, after one year of membership, Herr resigned from the expert panel of ARK’s voluntary krill fishery agreement. She now calls the entire voluntary agreement a “greenwashing” operation.

“The expert panel is not established to provide the best advice on how to mitigate harmful effects of the krill fishery on the marine environment,” Herr told Mongabay. “It was established to the very narrow focus to only evaluate the effects of the voluntary measures, and these were only designed for penguins, and to a limited extent, seals.”

Arata said he agreed that ARK’s voluntary measures were designed “to protect the breeding season of penguins.” Regarding the krill fishery’s potential impact on whales, he said, “any fishery operates at sea in places where they find resources. When you come across prey, you will find predators.”

“[A]ctually the management of [the krill] fishery considers a significant amount of krill to be left in the water for predators, including the whales. In 2019 they estimated a biomass of 60 million tons, and the idea is not to reduce that […] below 75%” over a 20-year period, Arata said.

Images and graphs from the study.
Fin whale supergroup, South Orkney Islands, January 2022. (A) Map showing where observations were made; yellow diamond shows location of observation; red box indicates outline of no-take South Orkney Islands Southern Shelf Marine Protected Area. (B) Four active krill fishing vessels, three registered in Norway and one in Chile. (C) Close-up views of part of supergroup. (D) Estimated distribution of group size based on number of blows visible at one time; vertical dashed lines represent 95% CI. (E) Panorama of whale blows (N = 143) from which the number of whales present was estimated; black box indicates location of krill fishing vessels. Photographs by Conor Ryan. Image courtesy of Ryan et al. (2023).

Stalemate on wildlife

Regulating the interaction between krill fisheries and whale populations in the Southern Ocean is part of the CCAMLR mandate. In recent years, however, CCAMLR has stalled on its own 2009 commitment to establish new marine protected areas (MPAs).

A CCAMLR special meeting held in Santiago, Chile, with the purpose of developing a roadmap to creating a representative system of Southern Ocean MPAs closed June 23 without any step forward.

“We did not achieve our goal, nor did we adopt further MPAs or any measures related to advancing marine conservation in the Southern Ocean,” Cassandra Brooks, assistant professor of environmental studies at the University of Colorado Boulder, who took part in the meeting as a member of the Scientific Committee on Antarctic Research, told Mongabay by email. “We resume negotiations in October 2023 for the CCAMLR annual meeting in Hobart, Tasmania, and I am hopeful we can make further progress then.”

Any progress toward the establishment of new MPAs during the special meeting in Santiago was blocked by delegates from China and Russia, according to Orazio Guanciale, CCAMLR commissioner for Italy. The two countries also asked attendees to reconsider CCAMLR’s Conservation Measure (91-04), which defines the entire strategy for the adoption of MPAs, Guanciale said. The two countries vetoed proposals to establish new MPAs in each of the six latest CCAMLR annual meetings.

“It isn’t based on science. It’s based on politics,” Arno Rosemarin, a researcher with the Stockholm Environment Institute and author of a report on the governance of CCAMLR, told Mongabay. “Most of the delegates to the meeting were scientists, or they know about science, while the Russians and the Chinese sent diplomats,” Rosemarin said.

The stalemate at the recent CCAMLR meeting on MPAs came just days after the signing of a landmark treaty to safeguard Marine Biodiversity of Areas Beyond National Jurisdiction. UN members adopted the treaty by consensus in New York on June 19, concluding nearly two decades of discussions.

“That pressure is on CCAMLR to actually resolve this problem,” Rosemarin said. “If they don’t work this out, then the CCAMLR could be designated as a fisheries management agency, which is basically what it is today.”


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