Evaluating threats to South Shetland Antarctic fur seals amidst population collapse

Abstract

Abstract Antarctic fur seals (Arctocephalus gazella) are an iconic marine mammal, an important component of Antarctic ecosystems, and a key indicator species for regional fisheries management. Recent studies have demonstrated Arctocephalus gazella is composed of at least four distinct subpopulations, including one breeding on the South Shetland Islands. These South Shetland Antarctic fur seals (SSAFS) are the highest latitude population of otariids in the world. As such, this subpopulation faces a unique array of environmental and ecological challenges, harbours a disproportionately large reservoir of genetic diversity for the species, and has experienced catastrophic population decline in the last 15 years (2008–2023). We review the array of current and potential threats to the successful recovery of SSAFS. If decision makers wish to promote resilience and support a robust population of this species with future recovery potential, actions are needed to address threats ranging from uncertain to critical, including debris entanglement, climate change, incidental mortality, and resource competition with the krill fishery. In particular, the risks associated with overlap in the spatial and temporal distribution of the young of the year and the krill fishery should be addressed carefully. There is an urgent need for updated population estimates for all Antarctic fur seal subpopulations, analysis on the population viability of the SSAFS, and further characterising summer and winter foraging behaviours to better inform potential conservation actions.