In the vast, icy waters of the Southern Ocean, a growing battle is unfolding beneath the waves. Endangered whale species, once hunted to the brink of extinction, are facing a new threat. But this time, their enemy isn’t harpoons—it’s industrial fishing for krill, a tiny but essential crustacean that whales rely on for survival.

The global demand for krill has soared in recent years. Once primarily harvested as feed for fish farms, krill is now coveted for its omega-3-rich oil, which is sold in dietary supplements. This surge in demand has put krill stocks at risk, raising concerns about the sustainability of the species and, more alarmingly, the survival of the whales and other marine animals that depend on it.

Krill: A Critical Food Source

Krill, shrimp-like creatures barely the size of a human thumb, play an outsized role in the Antarctic ecosystem. Baleen whales like humpbacks and blue whales rely on krill as their primary food source, consuming vast amounts during their annual feeding seasons. A single whale can consume up to six tons of krill each day, making these tiny organisms crucial for the whales' recovery from centuries of industrial whaling.

Krill is not only important for whales. Seals, penguins, and various seabirds all depend on krill, as do the larger Southern Ocean food webs, Oceana reports. Krill also plays a role in regulating global carbon levels by sequestering carbon dioxide from the atmosphere during their lifecycle. The organisms’ significance to both the marine ecosystem and global environmental health cannot be overstated, yet human demand for krill continues to grow unchecked.

According to a study from Stanford University, the increase in krill fishing overlaps directly with whale feeding grounds, particularly around the South Orkney Islands. This is where supergroups of whales have been observed feeding, a sight not seen since before commercial whaling devastated their populations.

But the trawlers are targeting the same dense swarms of krill that whales depend on to build their energy reserves for migration and breeding seasons, leading to direct competition between whales and industrial fishing operations, Fast Company reports.

Increasing Demand, Decreasing Supply

Krill fishing in the Southern Ocean has quadrupled in the last two decades, fueled by the growing aquaculture industry and the demand for omega-3 supplements, CU Boulder reports,. In 2022 alone, over 400,000 tons of krill were harvested from these waters, according to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). This figure represents a significant increase over previous years and coincides with the recent resurgence in whale populations, particularly humpbacks and fin whales.

Experts are concerned that there simply isn’t enough krill to support both the expanding human fishery and recovering whale populations. The Southern Ocean ecosystem has been in recovery since the 1986 moratorium on commercial whaling, with some species showing remarkable comebacks, Popular Science reports. Humpback whales, for example, are now at roughly 90% of their pre-whaling population levels in some areas. However, other species, such as the Antarctic blue whale, remain critically endangered, with populations still struggling to rebound.

Despite the recovery, the whales are facing the same scarcity of food that likely contributed to their near-extinction. The Stanford study indicates that krill populations are far lower today than before the advent of industrial whaling. This decline, attributed in part to the ecological role of whales in fertilizing the ocean with their feces, has caused some scientists to question whether the current krill biomass can sustain both an industrial fishery and whale recovery.

A Looming Crisis

Krill fisheries not only deplete the food available to whales but also pose direct physical threats. In recent years, multiple humpback whales have become entangled in the massive trawler nets used to harvest krill. These entanglements have resulted in several whale deaths and underscore the dangers posed by industrial fishing operations in shared waters, according to the Stanford study.

The future of krill management in the Southern Ocean is now in the hands of international regulatory bodies like the CCAMLR, which is scheduled to review catch limits in the coming months. Environmental advocates and researchers are pushing for stricter regulations that account for whale prey requirements. Without such measures, they warn, the fragile recovery of whale populations could be halted or even reversed.

As krill continues to grow in commercial value, balancing the needs of whales and the fishing industry becomes more challenging.

“It’s not a foregone conclusion that whale populations have to suffer because of higher levels of krill harvesting. With more research and careful management, we can ensure the coexistence of both whales and krill fisheries,” conservation biologist Matthew Savoca said in a study published in Nature Communications.

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