Guadalupe fur seal (Arctocephalus philippii townsendi, Brunner 2004)

The Guadalupe fur seal (Arctocephalus philippii townsendi or A. townsendi) was at the brink of extinction due to overhunting during the eighteenth and nineteenth centuries. Today, the Guadalupe fur seal remains classified as an Endangered species by Mexican law and as Threatened under the US Endangered Species Act of 1973. Currently, the entire population is estimated at around 40,000 individuals, with a single well-established breeding site on Guadalupe Island. Around 20 years ago, it was discovered that Guadalupe fur seals had recolonized San Benito Archipelago, which is 260 km southeast of Guadalupe Island. However, breeding activity at this site continues to be negligible with <1% of pups born here each year. It is likely that recovery of the Guadalupe fur seal depends on prey availability, which is influenced by oceanographic factors in the California Current Ecosystem (CCE). In this regard, differences in foraging habits have been found between the two colonies (Guadalupe and San Benito) in recent years and within the Guadalupe colony across decades. The population recovery rate has been lower than that observed for other pinnipeds that inhabit the CCE. Additionally, there are recent records of unusual mortality events along the US west coast; higher neonatal mortality due to starvation at Guadalupe Island; and marked reduction of the colony size at San Benito, which are all related to anomalous warm water events. These threats are intensified and more frequent because of climate change, which is the most significant threat to the species, especially given that over 99% of Guadalupe fur seals breed at one island, making it more vulnerable to this impact.