Systemic shifts in East Antarctic food webs: Adélie penguins adapt to declining krill via sea snail consumption

Indigenous Antarctic observers (e.g., Rapa Nui, Yaghan, and Mapuche communities) have long recognized the interconnectedness of Southern Ocean species, framing penguin behavior as a response to broader ecological imbalance rather than an anomaly. Their knowledge systems emphasize cyclical patterns of abundance and scarcity, which contrast with the linear, extractive models of Western science. However, their insights are systematically excluded from Antarctic governance, despite their potential to guide sustainable fisheries management.

The krill fishery in the Southern Ocean expanded rapidly in the 1970s–80s, driven by demand for omega-3 supplements and aquaculture feed, with CCAMLR quotas repeatedly set above scientific recommendations due to political pressure. Historical records from whaling eras show that krill populations were once far more abundant, suggesting that current declines are part of a century-long trajectory of exploitation. The 1980 Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) was designed to prevent overfishing but has repeatedly failed to adapt to climate change.

Comparative studies of seabird diet shifts in the Arctic (e.g., Brünnich’s guillemots consuming fish instead of crustaceans) reveal a global pattern of trophic cascades linked to industrial fishing and warming waters. Inuit communities in Nunavut have documented similar penguin-like seabirds (auks) adapting to reduced prey availability, using traditional knowledge to predict ecosystem tipping points. These parallels suggest that penguin behavior in East Antarctica is not an isolated event but part of a hemispheric-scale disruption.

Satellite tagging and stable isotope analysis confirm that Adélie penguins in East Antarctica are increasingly consuming sea snails (e.g., *Margarites* spp.) due to krill scarcity, a finding supported by decades of diet studies in the region. Climate models project a 30–50% decline in Antarctic krill biomass by 2100 under high-emission scenarios, exacerbating trophic mismatches. However, most research focuses on short-term behavioral adaptations rather than long-term evolutionary or demographic consequences.

In Antarctic art, penguins are often depicted as guardians of ecological balance, their survival tied to the health of the ice and sea. Indigenous Australian and Māori artists use seabird imagery to symbolize the fragility of marine ecosystems under colonial extraction. Spiritual traditions in Patagonia view penguins as messengers between land and sea, their diet shifts interpreted as omens of ecological distress.

Future scenarios predict that if krill fishing continues unchecked, Adélie penguin colonies in East Antarctica could collapse by 2050, with cascading effects on seals, whales, and seabirds. Climate-adaptive fisheries management—such as dynamic quotas tied to real-time krill biomass—could mitigate these risks but requires unprecedented international cooperation. Alternative protein sources (e.g., lab-grown omega-3) may reduce pressure on krill but face regulatory and economic barriers.

Small-scale fishers in Chile and Argentina, who rely on anchovies and sardines (competitors with krill), report declining catches and are rarely consulted in Antarctic governance. Women-led conservation groups in Patagonia, such as *Red de Mujeres por la Biodiversidad*, advocate for indigenous-led marine protected areas but lack formal influence in CCAMLR. Southern Hemisphere nations (e.g., South Africa, New Zealand) argue for stronger krill fishing regulations but are outvoted by industrial fishing blocs.