Phoca ursina Linnaeus, 1758 p.37; Type locality- Bering Island.
Callorhinus curilensis Jordan and Clark in Jordan et al., 1899 p.3; Type locality- Kuriles.
Otoes ursinus: Kuroda, 1938 p.22.
C. ursinus: Ellerman & Morrison-Scott, 1951 p.322; Won, 1958 p.436; Won, 1967 p.94; Won, 1968 p.331; Won & Smith, 1999 p.29; Kim 2004 p.190.
C. ursinus curilensis: Ellerman & Morrison-Scott, 1951 p.322.
Range: The long migratory route for C. ursinus courses mostly along the eastern coast and sometimes the southern shore of the Korean Peninsula (Fig. 60). This species frequently occurs on Dok-Island. Often, fishermen incidentally catch northern fur seals in the East Sea during winter.
Remarks: Marine biologists have long recognized the monotypy of Callorhinus ursinus. Mitochondrial DNA and microsatellite data identified a weak population structure across the extensive range of this taxon (Dickerson et al. 2010).
Conservation status: North Korea made C. ursinus and their habitat in Uam Ri, Hamgyeongbuk Province a Natural Monument. The Ministry of Environment of South Korea designated C. ursinus as an Endangered Species in 1997. Also, the Ministry of Land, Transports and Maritime Affairs named the northern fur seal a protected marine species in 2007.