Could There Be a Connection Between Autonomous Krill Harvesting and the Grey Whale Die-off?

One of MendoLocal.News' readers asked the question

Here’s one of the krill harvesters talking about how robots are revolutionizing krill harvesting in their own words: “I like to say Maritime Robotics is a solution provider,” says Eirik Mahout, senior product manager, Maritime Robotics. “But what makes us special is that we bring this together with maybe a hull or third-party vessel and the sensors the customer wants to use. If we have an unmanned vessel out there scouting for krill, we can fish much more efficiently, sustainably, and greener.”

The obvious answer to the reader’s question is that the grey whales feed in the Artic and the massive, record-breaking commercial krill industry operates in the Antarctic. While the industry may not be contributing to the grey whale die-off on the Pacific coast, they could threaten the southern right whale, another family of whales in the baleen whale suborder.

A 2024 study published by Nature Communications sounded the alarm. “Our calculations suggest an alarming possibility that we might harvest krill to the point where we do real damage to recovering whale populations,” the lead study author Matthew Savoca, a research scientist in the lab of Jeremy Goldbogen, associate professor of oceans in the Stanford Doerr School of Sustainability, told the Stanford Report.

What follows are excerpts from that article:

The researchers worked out that baleen whales effectively fertilize the ocean through their prodigious droppings, providing nutrients for the phytoplankton that krill eat. The upshot: The krill population must have been much larger, perhaps five times greater, than it is currently to have sustained the pre-whaling whale populations in the early 20th century.

“Krill is the foundation of the entire Southern Ocean ecosystem. They’re really the only thing that large whales eat down there,” Savoca said.

In the nearly 40 years since a global whaling moratorium went into place in 1986, some Southern Ocean species – particularly humpbacks – have made an impressive comeback. Yet this recovery has taken place against increasing competition with humans for the whales’ critical food source; over the past 30 years, the krill catch has quadrupled to around 400,000 tons annually and is set to expand further.

Savoca and colleagues calculated how much krill is left in the Southern Ocean for baleen whales, seabirds, and other predators to eat after industrial krill harvesting at current rates, compared to the estimated amount of krill available before industrial whaling began. “The basic math makes it pretty clear that the current krill biomass cannot support both an expanding krill fishery and the recovery of whale populations to pre-whaling size,” said Savoca.

Krill for all?

The study offers suggestions for how the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), an international organization established in 1980 that manages Southern Ocean fisheries, can help avert disaster.

Regulation of the areas and times of year when commercial krill boats can operate to minimize competition with whales is a starting point. The most important such region, according to the study, is a fairly small area (16,000 square kilometers) to the west of Coronation Island in the South Orkney group, a prime fin whale feeding ground where about 30% of all krill has been fished since 2000.

Krill fishing directly overlaps with whale feeding in this region, driving welfare concerns for the whales.

The researchers also suggest expanding the use of marine mammal exclusion devices to prevent accidental bycatch of whales entangled in krill nets, as has occurred recently with the documented deaths of at least four humpback whales across the 2021 to 2022 seasons.

As for the krill themselves, improved monitoring to bring in more data on krill egg and larvae hotspots could identify zones to ban or limit fishing. Additionally, fishing vessels could regularly sample krill swarms to avoid harvesting those in the midst of critical spawning periods.

The researchers hope their study will prompt more rigorous accounting and deeper investigations into krill predators and the krill themselves, ultimately forging a path ahead that preserves the delicate ecological balance in the Southern Ocean.

“It’s not a foregone conclusion that whale populations have to suffer because of higher levels of krill harvesting,” Savoca told the Stanford Report. “With more research informing careful management, this story of saving the whales can continue to be a conservation success.”