Unprecedented Records of Guadalupe and Juan Fernández Fur Seals in the Galapagos Archipelago

Abstract

[Extract] The Guadalupe fur seal (GFS; Arctocephalus philip-pii townsendi) and Juan Fernandez fur seal (JFFS; Arctocephalus philippii philippii) have a restricted distribution to islands in the North and South Pacific Ocean, respectively. GFS only breeds in Mexico, concentrating its population on Guadalupe and the San Benito Islands (Figure 1), with a regional abundance of around 40,000 individuals (Garcia-Aguilar et al., 2018; Hernandez-Camacho & Trites, 2018), while JFFS is limited to the Juan Fernandez Archipelago in Chile (Figure 1), with an estimated population of 20,000 animals (Osman, 2007). Both species were considered extinct by the end of the 1800s because of intense commercial hunting (Townsend, 1931; Hubbs & Norris, 1971). However, a small number of GFS and JFFS were discovered breeding on Guadalupe Island in 1954 and Alejandro Selkirk Island in 1965, respectively (Hubbs, 1956; Bahamonde, 1966). These populations grew slowly and colonized other nearby islands over time (Goldsworthy et al., 2000; Aurioles-Gamboa et al., 2010), surviving in caves or on inaccessible beaches, thereby maintaining their populations and probably facilitating the increase of their genetic diversity (Goldsworthy et al., 2000).