Decrease in the occurrence of the South American fur seal (Arctocephalus australis) in San Matías Gulf after a sudden episode of reoccupation

. The colonies of South American fur seals, Arctocephalus australis (SAFS), are currently experiencing population recovery, and as a consequence many coastal areas have been reoccupied. These areas are often haul-out sites used by SAFS for resting during the post-reproductive (winterly) season, and may be playing a key role in the population recovery process since they seem to be located close to winter feeding areas that are far from the breeding colonies. This study reports on the trend in abundance of SAFS in a recently reoccupied winter area, the San Matías Gulf (SMG). The trend was evaluated with generalized linear models between 2007 and 2017 in two sectors of the SMG, Islote Lobos, the only rookery of this species in the area, and the northwest marine area of the gulf. Both sectors showed a negative trend. For Islote Lobos, the best selected models estimated a mean annual rate between -12.2% and -17.6%, SAFS observados en 2007 pueden haber seleccionado otros hábitats durante los siguientes años. Sin embargo, para comprender los procesos de redistribución y recolonización se necesitan censos simultáneos en todo su rango de distribución.