 The southern ocean's changing physical properties can negatively affect the body condition of capital breeding marine mammals like the southern right whale. Over the last decade, these animals have experienced a decrease in body mass which could be linked to a decline in food availability due to changes in the environment. This is the first study to document a long-term reduction in the body condition of a capital breeder dependent on southern ocean productivity. Understanding how environmental change affects the bio-energetics of these animals is essential for predicting their resilience to climate change. This article was authored by Elsver Mulan, Terriann Thava, Maria Glaru, and others.