The Future of Antarctica's Whales Depends on Krill
Marine scientist shares what he learned on a month-long trip in one of the Southern Ocean's most remarkable feeding grounds
More than a century after whales in the Southern Ocean were hunted to near extinction, some species of the cetaceans have rebounded impressively while others, including blue, fin, and sei whales, are still struggling. All of which has led some scientists working in the region to focus their research on a major food source for whales: Antarctic krill, the tiny crustacean at the heart of the Southern Ocean food web.
Matthew Savoca, Ph.D., a principal investigator at the California Marine Sanctuary Foundation and a research scientist at Stanford University's Hopkins Marine Station, studies the human impact on marine ecosystems. His research has revealed how much recovering whale populations depend on krill, which led him to question how growing demand for krill products could affect the future of the Southern Ocean's wildlife.
In February and March 2026, Savoca led a scientific expedition to the South Orkney Islands, between Antarctic and South America, where researchers documented one of the world's most remarkable whale feeding grounds and gathered new data on the overlap between whales and industrial krill fishing.
Pew Bertarelli Ocean Legacy caught up with Savoca ahead of World Krill Day, which falls on Aug. 11.
This interview has been edited for length and clarity.
Q. You must love extremes, studying a miniscule food source for one of the world’s largest mammals in such a remote and forbidding location. What draws you to this work?
A. In short, yes, the whale-krill food web in Antarctica is fascinating! The longer backstory is that, in January 2022, we heard from our colleague Conor Ryan when their National Geographic expedition ship happened upon a group of about 1,000 fin whales near the South Orkneys. I don’t know if any of us who weren’t there would’ve believed it if there weren’t accompanying videos that we later analyzed. That group of whales turned out to be the largest group of whales that has been scientifically counted. Ever.
Also, in that location at the same time there were four fishing boats actively harvesting krill, the very species that those thousand whales were there to feed on. So, I became really interested in this overlap issue between krill fishing and baleen whales, which is why we visited the South Orkney Islands in early 2026. What we saw did not disappoint.
Q. Tell us about that South Orkney Islands trip. What did you see there, and why is this region so special?
A. The South Orkney Islands, a small archipelago about 300 nautical miles to the east of the Antarctic Peninsula, is an astonishing place where a combination of physical factors like ocean currents, seasonally melting and refreezing sea-ice, and bathymetry combine with biological factors like phytoplankton blooms and krill swarms to bring predators together in unbelievable numbers. Every day that we had good weather—which is a big “if” in that region of the world—we would see groups of 100-plus whales.
In over a decade of studying whales in different places around the world, I’ve rarely seen anything like that, but on this trip, we saw it on 10 separate occasions in just a few weeks. We also had tens of thousands of penguins and tens of thousands of albatrosses and other flying seabirds swimming and circling around almost constantly. And stunningly beautiful 3000-foot mountains and with glaciers spilling hundreds of feet into the sea. It is this incredibly remote, unbelievably spectacular portion of the planet that so few people get to see. I’m still pinching myself that we got to be some of those people.
Q. Why are Antarctic krill so vital to a fully functioning Antarctic food web?
A. A lot of people who study specific species like to make the case that their species is the most important. In the case of Antarctic krill in the open waters of the Southern Ocean, that case makes itself.
The Southern Ocean is what’s known as a wasp-waist food web, where there are numerous primary producers—phytoplankton such as diatoms, dinoflagellates, and Phaeocystis antarctica—and most of that photosynthetic biomass is funneled to just one species: Antarctic krill. Krill then feed numerous predatory species, creating an hourglass or wasp-waist-shaped food web.
Most of the charismatic Antarctic wildlife that people think about, from whales to penguins to seals, either have krill as a large component of their diet, or in the case of several of these species, eat Antarctic krill exclusively. In addition to being a central node of the food web, Antarctic krill are also the most numerous macroscopic species on Earth. Their biomass—somewhere around 300 million tons—rivals that of all of humanity. Beyond their ecological importance, they also sequester an estimated 20 million tons of carbon away to the deep sea every year through their fast-sinking fecal pellets, their molted exoskeletons, and their dead matter.
Taken together, Antarctic krill are not only one of the most important species in the Southern Ocean, but by many metrics, they are among the most important species on the entire planet.
Q. Your research shows that whales are recovering in the Southern Ocean in numbers not seen in a long time. How do Antarctic krill factor into this recovery?
A. The whales that we’re talking about are baleen whales, and these filter-feeding giants eat Antarctic krill almost exclusively. So, it goes without saying that Antarctic krill are of central importance to the recovery of these Southern Ocean whale populations.
Still, if we simply multiply how many whales there were in the Southern Ocean before 20th-century Antarctic whaling—about 2 million baleen whales of five different species—we can estimate the amount of krill needed to rebuild those whale populations to their historic numbers. Just to give you an idea, in just the Southwest Atlantic sector of the Southern Ocean, we’d need about 100 million tons of krill to feed the number of whales that were there before whaling. But there’s only 63 million metric tons of krill there now, obviously not nearly enough to recover whale populations to their historic size. We feel those numbers are representative of the gap throughout the entire Southern Ocean.
Q. What does this mean for the bigger picture?
A. The recovery of whales in the Southern Ocean is an ongoing conservation success story, but it’s unclear where it will end up. Some species, like humpback whales in the Southwest Atlantic sector of the Southern Ocean, are nearly fully recovered, but fin whales are only about one-third recovered in that same region. The story for Antarctic blue whales is much more dire; they are still only 1% recovered to their historic population size. And because of the massive size of fin and blue whales, and how many there were before whaling, it is unclear if they will ever be able to recover to that pre-whaling state in an era of rapid climate change and industrial krill fishing.
Q. Your recent studies have also raised concerns about growing competition for krill between wildlife and humans. What did your team find?
A. In brief, the main concern is competition for a shared food resource, and the fact that the wildlife can’t simply replace krill with another food source.
Q. What surprised you during your recent expedition to the South Orkney Islands?
A. What surprised me most on our trip to the South Orkney Islands was the consistent aggregations of wildlife. We knew that there were occasionally very large groups of whales and other predators that congregated near the islands. There are also other islands in that area of the world (e.g., Elephant Island and South Georgia Island) that host very large aggregations of predators. However, what I was not prepared for was that at the South Orkney Islands there were these huge aggregations every single day.
It’s not just that there are occasional huge pods of whales, enormous groups of penguins, and other predators when conditions are right, but in fact, there are huge congregations of wildlife in this area every day we were there. We are planning to go back to conduct similar work roughly a month earlier next year, so it will be interesting to see if the same aggregations are present then too.
Q. As people around the globe mark World Krill Day, what message would you like to convey to help them understand the need for conserving and responsibly managing this species?
A. If we protect krill, we protect the Southern Ocean. In an ecosystem that is so productive, so important to global biodiversity, carbon cycling and sequestration, in addition to being home to innumerable quantities of charismatic wildlife, the future of the Southern Ocean really boils down to one simple thing: the welfare of Antarctic krill.