Articles

The Most Pristine Ocean: Monitoring fishing effects on the Ross Sea foodweb

December 6, 2012

story by Grant Ballard
photo by Viola Toniolo
This article originally appeared in Meatpaper Issue Nineteen

 

Lone adélie penguin seen from Cape Crozier, Antarctica. Adélie penguins rely on sea ice for survival. The Ross Sea will be the last place on Earth with sea ice.

THE CLIMB TO THE TOP of Pat’s Peak from the four-person U.S. Antarctic Program hut at Cape Crozier takes a fit person about 15 minutes, and a bit of motivation, particularly after dinner. It is a solitary, aggravating (due to loose talus), and sweaty-then-cold experience. The rocky, exposed summit is about 900 feet above sea level and offers otherworldly views: the Ross Ice Shelf stretching out to the east in an expanse of unbroken, inconceivable whiteness; Mount Terror rising 10,500 feet to the west, often with an exotic lenticular cloud hovering near it like a giant jellyfish. This is a climb I’ve committed to muscle memory after having done it hundreds of times over the past 16 years. I have been coming here with a small team of ecologists to study the Ross Sea food web. In a way it has turned out to be all about fish.

From the top of Pat’s Peak one can survey the nearby Ross Sea for birds, whales, and seals (hint: They all eat fish), using binoculars and a telescope. One evening, about 12 years ago, I was on Pat’s Peak relishing the absence of wind and marveling at how the sea and sky merged in an indistinct, leaden horizon. As always, there were thousands of penguins porpoising nearby, coming and going from their colony of about 150,000 pairs. My eye was drawn to a flock of about 75 penguins farther off that seemed a little odd — their spacing was more ordered, the flock more organized. Several seconds later I realized it was a pod of killer whales, but they were much farther away than I had initially thought and leaping from the water in a very synchronized way — something I had never seen before. These are the kinds of tricks that Antarctica plays on you: the brain is constantly challenged to reassess scale, numbers, and magnitudes, and to be unashamed of mistaking a 15-foot marine mammal for a 2-foot flightless bird. The fact that there were 75 killer whales nearby was not one of the things that surprised me.

The Ross Sea is the most pristine ocean on the planet. For most of the year it is covered by vast amounts of sea ice (frozen ocean), which makes it nearly inaccessible. This ice turned back several explorers before James Clark Ross first successfully sailed into it in 1841, making the Ross Sea the last major stretch of ocean to be discovered by humans. It continues to be a challenging place for sailors to this day: It’s the only place on earth where sea ice is growing in extent, and it’s home to legendary windstorms. It also hosts mind-boggling numbers of animals, particularly top predators such as whales, large fish, penguins, and other seabirds. It serves as a reminder of what much of the world’s oceans must have been like before humans came along,leading many to consider it a “natural laboratory.”

Hundreds of scientists have worked in the Ross Sea since it was first discovered. Recent studies show that despite being relatively small, the Ross Sea is responsible for 11% of all the atmospheric carbon sequestered by the world’s oceans. Carbon sequestration is a process by which atmospheric carbon dioxide is captured, via photosynthesis and ocean circulation, and stored in deep marine sediments, thus helping to mitigate climate change. This is accomplished by ecosystem processes that are not yet fully understood and that may no longer be functioning in other, more degraded marine ecosystems.

Scientists are also fascinated by how species cope with the challenges of living in the harshest environment on earth. The animals that inhabit the Ross Sea have evolved special characteristics that enable them to deal with subfreezing ocean temperatures and to navigate around, through, and over the extensive sea ice. Several Antarctic fish species have antifreeze in their blood that enables them to survive in the 28.5°F water. Weddell seals can dive for over an hour, up to 2,400 feet, and then resurface to find that the ocean has frozen over; they then use their teeth to chew breathing holes through the new ice. Adélie penguins migrate thousands of kilometers to escape the Antarctic winter, often hitching rides on fast-moving ice floes. Emperor penguins have forgone the normal annual migration and instead make the crazy gamble of nesting on the frozen ocean in the darkness of midwinter, using their feet to protect their single egg (they are the only bird species that never needs to set foot on land). Ross Sea killer whales, which are the smallest killer whales in the world, feed exclusively on fish and can thus co-exist peacefully with the penguins and seals; in the Ross Sea their diet consists primarily of Antarctic toothfish, one of the species of “antifreeze fish,” known to be slow to reproduce and to grow larger than six feet and 300 pounds.

Since 1997 the toothfish have been targeted by fishing boats from New Zealand, South Korea, and several other countries, which are lured to these dangerous waters by the U.S. and European appetite for Chilean sea bass, which is the market name for Antarctic toothfish. Unfortunately for killer whales and Weddell seals, which also eat toothfish, these fish are very tasty to humans. The Ross Sea fishery is considered “exploratory” and is tightly regulated by CCAMLR (“cam-el-are,” the Committee for the Conservation of Antarctic Marine Living Resources). Even so, the fishery’s management plan would reduce the number of adult fish by half in the next 35 years. Scientists and environmentalists are alarmed, citing insufficient knowledge of the natural history of the species: Where does it breed? How frequently? How many are there? What eats them other than people? Just how dependent on toothfish are the killer whales and Weddell seals?

How will fishing of Antarctic toothfish affect killer whales and Weddell seals?

During our daily observations from Pat’s Peak it used to be common for us to see pods of 75 killer whales like the one described above. In recent years, however, I have not seen a single pod larger than 20 individuals, and the overall trend has been strongly negative, correlating exactly with the increased fishing pressure on Antarctic toothfish, their main food. CCAMLR estimates that the fishery has already reduced the numbers of toothfish in the region by about 20%, and it is now deliberating whether to move the fishing elsewhere and establish a marine reserve in the Ross Sea. It is a challenging prospect, due in no small part to the fact that the organization operates on a consensus basis — any one of the 25 member countries can block protection measures. Though CCAMLR’s mandate is different than most fisheries-management organizations’ because it specifically emphasizes the importance of conservation, in practice commercial interests have a strong influence. Recently I visited officials in Beijing to encourage their support for protection (the Chinese do not currently fish for toothfish), and their response sums it up pretty well: If there were no market for these fish, there would be no issue. While that is an oversimplification, it’s clear that consumers can, collectively, wield tremendous power in effecting change.

For more information about the effort to create a Marine Protected Area in the Ross Sea region, visit www.lastocean.org and www.antarcticocean.org.

 


VIOLA TONIOLO is an ecologist, writer, photographer, and mapmaker based in San Francisco. She was born and raised in Italy and hails from a food-obsessed family. She is happiest when her feet are on bare rock and her sights are set on something distant – preferably an iceberg, a seal, the ocean, or the next mountaintop.


GRANT BALLARD is a chief science officer at PRBO Conservation Science in Petaluma, California. He works in both ecology and bioinformatics and currently leads several projects investigating, communicating, and mitigating the effects of large-scale environmental change on ecosystems in western North America and the Southern Ocean.


This article originally appeared in Meatpaper Issue Nineteen
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