Macaroni penguins are the most numerous penguin species but face population declines linked to krill availability, climate change, and competition with commercial fisheries in the Southern Ocean.
Macaroni penguins that cannot find sufficient krill within their foraging range return to colonies in poor body condition, with reduced ability to sustain incubation or feed chicks. Chicks that receive insufficient krill grow slowly, are vulnerable to cold stress, and may be abandoned if parents deplete their reserves. Prolonged chick starvation causes suffering before abandonment or death. The combination of warming-driven krill decline and commercial harvesting creates cumulative pressure on macaroni penguin food security. Protecting penguin foraging zones from commercial krill fishing is a concrete welfare and conservation intervention with measurable potential impact.