Mercedes “Mecha” Santos, the lead scientist offering guidance on the creation of a marine protected area for the Antarctic Peninsula, on her latest expedition to the continent. Mercedes Santos

Penguins are abundant in the Antarctic Peninsula. About 1.5 million pairs of Adélie, gentoo and chinstrap penguins call this icy region home. But they face threats from a rapidly warming climate and concentrated commercial fishing for their main food source: krill. Greater marine protections for the Antarctic Peninsula region would make this unique ecosystem more resilient to climate change and provide relief from added stressors, such as commercial fishing.

In celebration of World Penguin Day, Pew caught up with Mercedes “Mecha” Santos, an Argentinian who has studied Antarctic penguins for nearly 10 years and is senior vice chair of the scientific committee for the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the management body charged with conserving biodiversity in Antarctica’s Southern Ocean.

She is one of the scientists who led the development of the proposal for a marine protected area (MPA) in the Antarctic Peninsula region that Argentina and Chile submitted at CCAMLR’s meeting in October. The proposal would limit krill fishing in prime penguin foraging areas and fully protect the spawning and nursery habitats of krill and other ecologically valuable fish species such as toothfish on the western side of the peninsula. It also protects other finfish species on the northwest side of the peninsula that were overexploited in the 1970s (e.g., marbled rockcod and mackerel icefish) and are still struggling to recover.

Q. How did you become interested in penguins? Which is your favorite species and why?

Santos: While I was doing my Ph.D. fieldwork with predatory seabirds, south polar skuas, I was drawn to how lovely and hard-working penguins were, and though they were not my primary focus, I started helping the penguin team by conducting research on the species. Researcher Alejandro Carlini and his team always helped me with my fieldwork, and in return, I did the same for them. Antarctica is the best place to learn about teamwork! Unfortunately, Alejandro passed away prematurely, and because of my loyalty to him and my desire to continue to support the long-term program on penguins that he started (25 years ago now) together with Nestor “Coco” Coria, I kept running this research. This is how penguins became the center of my studies. I love them all, but I guess that Adélies are my favorites—they are little nervous guys.

An Adelié penguin, Santos’ favorite species. Javier Negrete Courtesy of Mercedes Santos

Q. The Southern Ocean is known for its outstanding biodiversity, yet some populations of penguins in Antarctica have been diminishing. What are the major reasons?

Santos: There is no single explanation for that. It has been shown that the decline in krill abundance, sea ice receding, and increase in whale populations (which means an increase in competition for krill), and snow accumulation in penguin breeding sites all factor into the population decrease. Also, considerable discussions have taken place in relation to fishery and tourism activities, although there has been no consensus about the magnitude of those impacts. To adequately protect penguins, we must consider the increased variability in the ecosystem and the difficulty to predict future conditions in the light of climate change. More uncertainty must mean [taking] a more precautionary approach in managing living resources.

Q. Why is safeguarding Antarctic krill, a thumb-size crustacean, so important to penguins and the region’s ecosystem?

Santos: Antarctic krill are a key component in the Antarctic food web. Many species (from fish to whales) rely on them as their principal prey. In particular, Pygoscelis (brush-tailed) penguins feed on krill during the breeding season in the summer. The observed declines in breeding populations could be related to a low abundance of Antarctic krill, their main prey, resulting in low breeding success. Fewer chicks every year means less adults in the future. But a low abundance of krill will also affect juvenile penguins, leaving slight (or underweight) young penguins with reduced chances of surviving winter—and thus fewer birds will return to the colony to breed.

Antarctic krill also play an important role in transporting organic carbon to the seabed. In the Southern Ocean, krill produce significant amounts of dead organic matter. Feces drop rapidly into the ocean depths, assuring long-term carbon storage. Also, as the major prey item in the Southern Ocean, krill play a key role in transferring iron to large marine animals.

Q. During the 16-plus years you have conducted research in the Antarctic Peninsula, what environmental changes have you seen in the region? What are the biggest threats to this ecosystem, and what should be done to address them?

Santos: I have seen retreating glaciers, more storms, and an increased number of years with high snow accumulations, as well as anomalous high temperatures. Sixteen years is a very short period of time to notice these changes!

The biggest threats are related to the increased variability in the ecosystem due to the effects of climate change. On top of that and because of that uncertainty, if we fail to agree on robust management of human activities (that includes tourism, fisheries and science), we will not be able to adequately protect this ecosystem and all the cultural, climate and economic services that it provides to humanity.

Marine ecologist Mercedes Santos holds a gentoo penguin. Adrian Garaycochea Courtesy of Mercedes Santos

Q. Can you explain why large, permanent, no-take marine reserves are so important for penguins and other species in the Peninsula region, and for the overall Southern Ocean?

Santos: The size of an MPA should be determined by the specific conservation objectives for each MPA and the species and habitats targeted for protection.

Our proposal for an MPA around the Antarctic Peninsula (D1MPA) recommends a size based on the different level of protection that CCAMLR’s international scientific community agreed is needed for the area. This proposal includes protections for most of the areas considered important for birds, mammals, fish, and zooplankton, and includes areas where important benthic (seafloor) and pelagic (open water) ecological processes occur. In addition, because this area is particularly susceptible to the effects of climate change, protecting biodiversity effectively relies on MPAs that accommodate potential shifts in habitats. The proposed MPA for the Antarctic Peninsula encompasses representative habitats—protecting biodiversity for decades into the future—and hence has the potential to contribute substantially to the climate resilience of all biota and ecological processes in the area. When we designed the MPA model, we took into account possible future scenarios. It’s fair to say that the Antarctic Peninsula MPA proposal is of the most scientifically rigorous caliber, with input from a wide variety of stakeholders—from researchers to industry and civil society.

Q. In 2016, CCAMLR designated 2.06 million square kilometers [almost 800,000 square miles] of the Ross Sea as the world’s largest protected area. How do you think the commission could replicate that decision by consensus—and fulfill its commitment to create a network of marine protected areas throughout the Southern Ocean?

Santos: Every time I sit at that big table (CCAMLR) I think about all the different visions (and interpretations) about marine protected areas. As a non-English speaker (and, believe me, language IS a limitation in these discussions) and a female Antarctic scientist, I have a strong commitment to the idea of trying to consider all these different views. I know, it is not easy. I get upset often, but I am convinced that to reach consensus as we did with the Ross Sea MPA, the people around the table need to allow for honest discussions, and to listen without judgment. We need to keep these discussions as fair as possible. We also need high-level political involvement to support this process.

In the end, to reach consensus in an Antarctic international context, we need to meet in the middle—to find the right balance—to secure conservation while allowing rational use, not only for the present but also for the future.