An interview with Nils Hoem, Chief Scientist at Aker BioMarine
Antarctic krill may be small, but genetically it is a giant. At the heart of every living organism lies its genome – the complete set of DNA instructions that determines how the body is built, how it functions, and how it adapts. By studying a species’ genome, scientists can uncover not only how it survives today, but also how it has endured environmental changes over millions of years.
Krill’s genome is remarkable. With one of the largest genetic codes known in nature and a finely tuned system of daily and seasonal rhythms, krill has developed a biological toolkit that makes it one of the most adaptable species on Earth.
The world’s largest genome
When scientists describe the krill genome, the numbers make even human DNA look modest.
“For Antarctic krill, we are talking about roughly 48 billion base pairs. Humans have about three billion. This is among the largest genomes known for any living organism,” explains Hoem. Much of this size is due to so-called jumping genes—DNA elements that can move around within the genome. Once dismissed as genetic “noise,” these transposable elements are now understood as a kind of archive of genetic experience, helping krill to adapt across millions of years of environmental change. The genome also reveals that krill has an unusually strong set of genes controlling rhythm—both circadian and seasonal.
“In Antarctica, light and seasons play a decisive role, and krill’s entire biology follows these rhythms. Krill molts roughly every 20 days, grows quickly when conditions are good, and can even shrink in times of scarcity. All of this is regulated by rhythm genes,” says Hoem.
A resilient keystone species
Evolutionary analysis shows that Antarctic krill traces its roots back tens of millions of years, surviving both ice ages and warm periods.
“It has endured massive shifts in climate and ecosystems, which is why we see it as such a resilient species. Krill is biologically built to withstand change,” Hoem notes.
In public debates, krill is sometimes portrayed as vulnerable and threatened. The reality is more nuanced.
“Krill is robust and highly adaptable. It forms enormous populations in the Southern Ocean and has life-history traits like rapid regeneration and highly efficient plankton feeding. That doesn’t mean we can be careless—responsible management is essential—but the idea of krill on the verge of collapse is simply not correct,” Hoem emphasizes.
Krill is also one of the ocean’s most efficient “machines.”
“It is a very active swimmer and a master filter-feeder. You could say that what we’re really doing is harvesting algae through krill. They collect the energy from the ocean’s smallest plants and form the foundation for the entire food web of the Southern Ocean,” he explains.
For scientists, genome mapping is far more than curiosity. It provides crucial insight into how ecosystems function in Antarctica.
“Genomic data gives us a better understanding of how sunlight, sea ice, currents, and plankton connect through krill. At the same time, this knowledge allows us to manage the resource more wisely. When we understand krill’s biology of adaptation, we can ensure that harvesting takes place within nature’s boundaries,” says Hoem.
Asked to summarize the secret of krill’s success, Hoem points to three words:
“Scale, rhythm, and flexibility. A gigantic genome filled with jumping genes, precise rhythm control, and a body that can reset itself rapidly—from molting to migration. That’s what makes krill so resilient. As long as we manage it wisely, krill is not a species we need to fear for.”
Nils Hoem
Nils Hoem, M.Sc. (pharm), PhD, is a licensed pharmacist with master’s and doctorate degrees in pharmacology from the University of Oslo. He is currently Chief Scientist at Aker BioMarine in Oslo, where he has led and participated in preclinical and clinical research as well as in process and product development. Hoem has also been involved in basic research into Antarctic krill biology and ecology in Western Antarctica, where krill harvesting takes place.
Antarctic krill (Euphausia superba)
Genome size: ~48 billion base pairs – the largest sequenced genome of any animal
Molting cycle: Every ~20 days; can shrink or grow depending on food availability
Biomass: Close to 400 million tons in the Southern Ocean, making Antarctic krill one of the largest single-species biomasses on Earth.
Feeding: Filter-feeds on phytoplankton, transferring energy to whales, seals, penguins, and fish
Conservation status: Listed as Least Concern by the IUCN, but requires responsible management due to its role as a keystone species
Fisheries management: The 2025 FAO report found Antarctic fisheries, including krill, to be 100% sustainably managed – a result that highlights the effectiveness of CCAMLR’s precautionary system.