Zalophus japonicus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Carnivora Otariidae

Scientific Name: Zalophus japonicus (Peters, 1866)
Common Name(s):
English Japanese Sea Lion
Zalophus californianus ssp. japonicus (Peters, 1866)
Taxonomic Notes: The Japanese Sea Lion has sometimes been considered a subspecies of Zalophus californianus, Z. c. japonicus. Rice (1998) argued for the retention of Z. californianus, Z. japonicus, and Z. wollebaeki as distinct species without providing new evidence. From studies of skull morphology Brunner (2003) argued for species status for these three taxa. In addition, Sakahira and Niimi (2007) and Wolf et al. (2007) provide genetic evidence that Z. japonicus is best considered a separate species.

Assessment Information [top]

Red List Category & Criteria: Extinct ver 3.1
Year Published: 2017
Date Assessed: 2014-10-26
Assessor(s): Lowry, L.
Reviewer(s): Burkanov, V.
Contributor(s): Aurioles, D. & Trillmich, F.
Facilitator/Compiler(s): Lowry, L., Ahonen, H., Chiozza, F. & Battistoni, A.
The species is listed Extinct because there have been no documented reports of Z. japonicus since the late 1950s, despite extensive marine mammal research effort taking place within its former range. The last credible report was 50 to 60 individuals on Takeshima (Dokdo) ( in 1951 (Rice 1998). Individual sightings reported as recently as 1974 and 1975, cannot be confirmed; confusion with escaped Z. californianus cannot be ruled out.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

According to Rice (1998) Japanese Sea Lions formerly were known from the northwest Pacific where they occurred along the coasts of Japan, the Democratic People’s Republic of Korea, the Republic of Korea, and Russia at Sakhalin Island and southern Kamchatka. Burkanov (pers. comm.) says that the only reliable report of Japanese Sea Lions was of an animal shot in 1949 at Moneron Island in the Sea of Japan at the southwest corner of Sakhalin Island. He concludes that they occasionally occurred in the southern Kuril Islands but not at Kamchatka as Rice (1998) had stated.

Countries occurrence:
Regionally extinct:
Japan; Korea, Democratic People's Republic of; Korea, Republic of
FAO Marine Fishing Areas:
Regionally extinct:
Pacific – northwest
Additional data:
Upper elevation limit (metres):10Lower depth limit (metres):500
Range Map:Click here to open the map viewer and explore range.

Population [top]


Estimates of historical population size are not available. Over-harvesting by Japanese commercial fishermen caused a drastic decline in abundance in the early decades of the 20th century and commercial harvests ended in the 1940s when the population was virtually extinct (The Sixth Extinction Website 2014). The last confirmed report was of 50-60 animals on Takeshima Island (Dokdo)  in 1951. Individual Sea Lions were reported in the region in 1974 and 1975 but their specific identity was not verified (Rice 1998). Most authorities, including IUCN and the Society for Marine Mammalogy, consider the Japanese Sea Lion to be Extinct.

Additional data:

Habitat and Ecology [top]

Habitat and Ecology:

Very little information exists on the biology of Japanese Sea Lions but it is assumed that they were generally similar to California Sea Lions. It is said that male Japanese Sea Lions were dark grey and weighed 450-560 kg, reaching lengths of 2.3 to 2.5 m. Females were smaller at about 1.6 m long with a lighter colour than the males. Their rookeries were on open sandy beaches and they preferred to rest in caves (Red Data Book 1994, Shimane Prefecture 2004).

Systems:Terrestrial; Marine
Movement patterns:Unknown
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: Japanese Sea Lions were harvested for their skins, whiskers, internal organs, and oil, and were also captured for the circus trade. The species is now Extinct.

Threats [top]

Major Threat(s):

Japanese Sea Lions were harvested for their skins, whiskers, internal organs, and oil, and were also captured for the circus trade. Those takes, in combination with persecution by fishermen and perhaps shooting by soldiers, likely caused their extinction (Wikipedia 2014).

Conservation Actions [top]

Conservation Actions:

Japanese Sea Lions are likely to now be Extinct. However, South and North Korea, Russia, and China have indicated that they will collaborate on bringing back the Japanese Sea Lion in the Sea of Japan. That effort would involve searching Russian and Chinese waters and if animals are found some would be taken to the Sea of Japan. If not, California Sea Lions might be translocated from the United States (The Extinction Website 2014).

Amended [top]

Amended reason: Dodko, an alternate name for Takeshima Island has been added to the distribution and rationale sections of this assessment.

Citation: Lowry, L. 2017. Zalophus japonicus (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T41667A113089431. . Downloaded on 19 September 2018.
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