In the waters off the northern tip of the world's southernmost continent, one of the most important creatures is also the most profitable: pinky-length Antarctic krill.

These swarming, translucent, shrimp-like creatures are eaten by almost everything here—fish, penguins, seals, and whales. But krill also support a multimillion-dollar global fishing industry. They get sucked into nets and ground into meal to feed aquarium fish or farm-raised salmon and get squeezed for their oil, which is used in pharmaceuticals, including in the United States.

Now, with climate change rearranging life along the western Antarctic Peninsula, scientists and marine advocates have been warning that wildlife—particularly penguins—are under far too much stress. Krill fishing, they say, could be making things worse.

Monday, after years of negotiations, a majority of the fishing industry formally agreed to stop hauling in krill from around the peninsula's troubled penguin colonies. The industry also committed to helping set up a network of marine protected areas in coming years to better protect marine animals.

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"We wanted to show that we are out in front, that we are committed to protecting wildlife in Antarctica," says Kristine Hartmann, executive vice president of Aker BioMarine, a Norwegian krill-fishing company and the largest in the world. "We see this proposal as just a first step."

Reaction has been largely positive.

"The news is very exciting and promising," says Kim Bernard, an assistant professor and krill expert at Oregon State University.

Says Heather Lynch, a penguin expert and associate professor with Stony Brook University, "Now that we have really good information on where penguin colonies are, krill companies can operate with far less impact. It's clear that there can be a win-win—they can catch what they need and still avoid the precious areas."

The question now: is that enough?

Base of the Food Chain

There are billions of krill all around Antarctica. But most of the fishing along the White Continent takes place around the tip of the Antarctic Peninsula, the region hardest hit by climate change.

Along the western side of the peninsula winter temperatures have risen 9 degrees Fahrenheit in 40 years. The sea ice that coats the water much of the year now appears later and disappears sooner. More precipitation falls as rain.

The result: colonies of the western peninsula's only truly Antarctic penguin species, the Adélie penguin, have seen dramatic declines. Silverfish, krill-eaters that once were a penguin staple, have disappeared entirely from some areas. At the same time, the number of adaptable gentoo penguins, used to warmer waters and common in Argentina and South Africa, have exploded.

Meanwhile, leopard seals, solitary animals that rely on sea ice as hunting platforms, now often are found in groups, hunting penguins closer to shore. They also feed more on other animals. Humpback whales, which used to migrate north when the ice returned, now stick around longer and eat even more krill. And that's just what is known. The region is simply too big to understand the impacts on many other species, from crabeater seals to sea birds like blue-eyed shags and skuas.

View Images Krill serve as the base of a food chain that supports many marine animals, from seals to whales. Photograph by BILL CURTSINGER, National Geographic

The impact of fishing on wildlife is not entirely clear. Fishing quotas allow them to take just a fraction of available krill, and the industry never reaches that quota. But a recent study by scientists with the National Oceanic and Atmospheric Administration showed that "direct overlap of krill-dependent predators with the krill fishery" was common. The results were "consistent with modeling work that demonstrates the krill fishery can pose risks to krill-dependent predators."

Meanwhile researchers with the British Antarctic Survey had convinced the United Kingdom to press a consortium of nations that oversee fishing in Antarctica to seek a ban on krill fishing near coasts adjacent to the peninsula during summer. Fishing managers had not moved to do that, so Greenpeace and other environmental groups began pushing the krill industry to abandon its traditional waters. Aker BioMarine, meanwhile, started meeting with scientists on its own to seek ways it could fish more sustainably without posing risks to wildlife.

All that culminated in this week's announcement.

Protecting Penguins

The new agreement is the first commitment of its kind. Fishing companies from Norway, China, Chile, and South Korea represent about 85 percent of the krill harvest. They agreed in 2019 to avoid fishing near penguin colonies during the breeding season. They committed in 2020, however, to staying 30 kilometers or more away from penguin colonies all year long.

"The main zones are around gentoo penguins, around islands where chinstrap penguins breed, and on the tip of the peninsula where Adélies have their colonies," says Cilia Holmes Indahl, director of sustainability for Aker BioMarine.

At the same time, the companies set up a plan to work with environmental advocates to support the adoption of marine protected areas around the region—not just in the Weddell Sea, where fishing is rare, but in the western peninsula and nearby Scotia Seas, the heart of the fishing grounds.

They also agreed to adapt a best-practices model used by fishing groups in other parts of the world, and to be more transparent about when and where they are off-loading their product.

And while not all krill-fishing companies signed the agreement, those that did not are seeking membership into an industry alliance that would require them to be party to the guidelines.

"It gives me great hope that such a large percentage of the Antarctic krill fishing companies have agreed to recognize the proposed no-take zones along the peninsula," says Bernard at OSU.

But with so much changing so fast in Antarctica, follow-through is key. And it will be a few years before the industry's commitment is truly tested.

One concern is that voluntary restrictions on fishing could slow momentum toward wider and more longterm marine protection in the Antarctic, says Lynch, at Stony Brook. Another is that this agreement is focused largely on penguins, while scientists are still learning about what other animals need to survive. As a result, there's no guarantee that these restrictions ultimately would be enough to protect sea life.